Greenbone AG

OPENVAS: The new name for proven Greenbone security

More than 15 years, OPENVAS has stood for excellent open source security worldwide – from small businesses to public institutions to operators of critical infrastructure. OPENVAS is developed by Greenbone and is behind both Greenbone’s enterprise products and the community versions. The OPENVAS brand inspires global confidence in a highly developed open source solution that stands up well against proprietary competitors.

From now on, we are placing the name OPENVAS at the center of all our activities. Our proven solutions and new products will now appear under a single, strong brand: OPENVAS.

Why we chose OPENVAS

OPENVAS is internationally recognized, stands for trust and open source, and clearly describes what it’s all about: identifying and minimizing digital risks. With the new naming scheme, we are making our solutions even more understandable, functional, and globally consistent. Originally intended only as the name of a technical component, the actual vulnerability scanner, the name has itself as the designation for our established product portfolio. We are happy to embrace this and use our open source established OPENVAS brand in all our product names.

For our users, customers, and partners, this means that everything you value about our solutions remains the same — just under new, more descriptive names. And there’s more to come this year: container scanning, agent-based scanning, a new REST API, and much more.

What does this mean for you specifically?

  • What you know stays the same: Your solutions will work as usual, including all services and security updates.
  • Names that create clarity: Each product name now directly describes its function – saving time and avoiding misunderstandings.
  • Strong brand, clear communication: We operate nationally and internationally under a single name – OPENVAS.

Our proven goal: to offer you the best solution for minimizing digital risks quickly, easily, and transparently.

What does this mean for our existing appliance products?

Our existing products will continue to be updated as usual. At the same time, they will be given new names, with OPENVAS always at the center.

A few examples: OPENVAS SCAN is the new product name for the Greenbone Enterprise Appliances, the while designations will remain unchanged. Familiar performance Greenbone Enterprise EXA will become OPENVAS SCAN EXA, and Greenbone Enterprise 600 will become OPENVAS SCAN 600.

Our free community products will of course continue to be available. We are using the name OPENVAS COMMUNITY EDITION for our free appliance and OPENVAS COMMUNITY FEED for the associated data feed with vulnerability tests and security information.

Greenbone remains – OPENVAS becomes new brand name

Greenbone remains the name of our company – headquartered in Germany and with our subsidiaries in the UK, Italy, and the Netherlands. The name Greenbone has become well established in German-speaking countries, which is why we have decided not to rename Greenbone AG as OPENVAS AG. Internationally, we are much better known as OPENVAS and therefore will operate under the OPENVAS brand: OPENVAS UK, OPENVAS IT, OPENVAS NL.

By strengthening our OPENVAS brand, in over 150 countries around the world we are making our mission visible: to make cybersecurity understandable, trustworthy, and accessible.

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Joseph Lee

Threat Report June 2025: A Cyber Combat of Attrition

The 2025 IOCTA report from Europol warns that demand for data on the cybercrime underground is surging. How much data has been stolen exactly? Determining exact numbers is impossible. However, the personal information of 190 million individuals including Social Security Numbers (SSN), was stolen from Change Healthcare in a single breach. That’s more than half of the total US population exposed in one incident. That incident pales in comparison to the 2024 National Public Data Breach, which included 272 million distinct SSNs, 420 million distinct addresses, and 161 million distinct phone numbers. In 2024, Europe saw approximately 363 breach notifications per day across surveyed EEA countries. Now, new strains of destructive wiper malware are emerging. In comparison, victims of data theft may soon be considered the “lucky” ones.

Cyber defenders are in a battle of attrition. Managing the continuous onslaught of new threats is a monumental and critical task. In this month’s threat report, we provide insight into the latest wave of wiper malware, new actively exploited vulnerabilities, and emerging threats shaping the global cyber conflict.

New Wave of Wipers Enter the Cyber Combat

Cisco Talos just observed a previously unknown wiper malware dubbed “PathWiper”, leveraged in a destructive attack against Ukrainian critical infrastructure. Wiper most often gets deployed during Cyber Warfare (CW) campaigns, when financial gain is not the primary motive. Whereas ransomware coerces victims into paying for the return of their encrypted data, wipers simply destroy it. Wipers have been used since the start of the Russia-Ukraine war. HermeticWiper was deployed against Ukraine in 2022, crippling government agencies and critical services hours before Russia first invaded.

Cybersecurity analysts also recently noted an emerging ransomware-as-a-service (RaaS) group, Anubis, which has added a wiper option to their custom ransomware payload. Amidst heightened geopolitical tensions, it’s plausible that nation-state threat actors will incentivize willing RaaS operators and hacktivists to carry out destructive attacks for impact.

Wiper attacks themselves aren’t new. Shamoon (aka Disttrack), discovered in 2012, was the first major Wiper malware. Suspected to be developed by Iranian threat actors, it was used to attack Saudi Aramco and other Gulf state organizations. Masquerading as ransomware, NotPetya was another prominent wiper strain that emerged in 2017 with global impact.

Organizations, especially critical infrastructure, need to consider the potential impact that wiper malware could have on their resilience. What if paying ransom is not an option? A well designed backup strategy can enable full or partial data recovery, but downtime also has a financial impact and has even recently resulted in loss of life. Ensuring that mean-time-to-recovery (MTTR) objectives can be realized is key to operational continuity. Of course, diligently closing security gaps before threat actors can exploit them is also essential to a proactive cyber strategy.

Sorting True Risk from “AI-Slop”: Linux CVEs in Flux

The days when Linux attracted fewer cyber attacks have long passed. Linux systems are increasingly targeted by sophisticated actors. Last year, the number of Linux kernel CVEs (Common Vulnerabilities and Exposures) also exploded: the Kernel CNA (CVE Numbering Authority) assigned an average of 55 new CVEs per week in 2024. This growth is sometimes attributed to AI uncovering bugs which are not actually security risks – dubbed “AI slop”. Curl’s creator, Daniel Stenberg, even posted a notice banning “AI slop” bug reports. A related bug report discussion raised the concern of “an attack on our resources to handle security issues”.

On the risk and patch management side of the coin, many defenders don’t have the luxury of conducting a deep investigation into each CVE’s technical feasibility. Conducting technical assessments and analyzing “patch diffs” takes enormous amounts of time. The resulting battle of attrition pits security teams against the clock. To prioritize remediation, they rely on CVSS (Common Vulnerability Scoring System), EPSS (Exploit Prediction Scoring System), exploit status, and environmental factors such as compliance requirements and operational criticality. Security leaders want to see evidence that progress is continuous and that security gaps are closed. This is truly the benefit of using a vulnerability management platform such as Greenbone.

That being said, here are some new high-risk Linux privilege escalation CVEs that gained attention this month:

  • CVE-2023-0386 (CVSS 7.8): Now deemed actively exploited, the Linux kernel’s OverlayFS subsystem allows escalation to root-level by abusing how files with special privileges are copied between certain mounted filesystems.
  • CVE-2025-6019 (CVSS 7.0): A flaw found in Fedora and SUSE distros allows non-root users in the “allow_active” group to execute privileged disk operations such as mounting, unlocking, and formatting devices via D-Bus calls to “udisksd”. The vulnerability is considered easy to exploit, and a public PoC (Proof of Concept) is available, increasing the risk.
  • CVE-2025-32462 and CVE-2025-32463: Two local privilege escalation vulnerabilities were fixed in Sudo 1.9.17p1, released on June 30, 2025. CVE-2025-32462 allows local users to abuse the –host option to escalate privileges on permitted hosts, while CVE-2025-32463 permits unauthorized root access via the —chroot option, even when not explicitly allowed in the sudoers file.
  • CVE-2025-40908 (CVSS 9.1): Unauthenticated attackers can modify existing files simply by processing a crafted YAML file as input, due to improper use of the two-argument open call. Vulnerable systems include any Perl applications or distributions (like Amazon Linux, SUSE, Red Hat, Debian) using YAML‑LibYAML before version 0.903.0.

CVE-2025-49113: A Critical Severity CVE in RoundCube Webmail

A recently disclosed vulnerability tracked as CVE-2025-49113 (CVSS 9.9) in RoundCube Webmail allows authenticated attackers to execute arbitrary code on a RoundCube server. A poorly designed PHP deserialization operation [CWE-502] fails to properly validate user input, allowing the “_from” parameter to carry malicious serialized code. Attackers who successfully exploit the bug can potentially gain full control over the RoundCube server to steal data and install command and control (C2) tools for persistent access.

Although CVE-2025-49113 requires valid credentials for exploitation, admin credentials are not required. Technical analysis [1][2], PoC exploits [3][4], and a Metasploit module are available, increasing the potential risk for abuse. An EPSS score of 81 indicates an extremely high probability of exploitation in the near future. Meanwhile, the researcher who discovered the flaw claims that exploit kits are already for sale on underground cybercrime forums. Numerous national CERT agencies have issued alerts for the flaw [5][6][7][8][9], while Shadowserver reported over 84,000 exposed Roundcube services existed in early June.

Greenbone Enterprise Feed includes remote version detection [10][11] and Linux Local Security Checks (LSC) [12][13][14][15][16][17] to identify vulnerable instances of RoundCube Webmail (versions prior to 1.5.10 and 1.6.11). Users are encouraged to apply updates with urgency.

New Critical CVE in Cisco ISE Cloud Has PoC Exploit

CVE-2025-20286 (CVSS 10) is a new flaw affecting Cisco Identity Services Engine (ISE) cloud deployments on AWS, Azure, and Oracle Cloud Infrastructure (OCI). The bug could allow unauthenticated, remote attackers to access sensitive data, perform some limited administrative operations, modify system configurations, and disrupt services. Due to poor software design, identical access credentials [CWE-259] are generated and shared across all connected ISE instances running the same release and platform.

Cisco has acknowledged the existence of a publicly available exploit. The vendor also stated that the vulnerability is only exploitable when the Primary Administration Node is deployed in the cloud. On-premises deployments and several hybrid/cloud VM solutions are not affected. Overall, the widespread use of Cisco ISE in enterprise networks and the availability of exploit code make CVE-2025-20286 a high-risk vulnerability for those with affected configurations. Greenbone includes a version detection test to identify instances that may be vulnerable.

CitrixBleed 2 and Another Actively Exploited Flaw in Citrix NetScaler ADC and Gateway

Dubbed “CitrixBleed 2”, CVE-2025-5777 (CVSS 9.3) is an out-of-bounds read [CWE-125] vulnerability affecting Citrix NetScaler ADC and NetScaler Gateway, which allows unauthenticated, remote attackers to steal valid session tokens from memory by sending malformed HTTP requests. CVE-2025-5777 is due to insufficient input validation – unfortunately, a common, yet easily preventable root cause of software bugs. Exposure of session tokens allows impersonation of legitimate users, resulting in unauthorized access. Security experts speculate that exploitation is imminent, drawing parallels to the original CitrixBleed (CVE-2023-4966) vulnerability leveraged by ransomware groups in high-profile breaches.

Another flaw, CVE-2025-6543 (CVSS 9.8), also affecting Citrix NetScaler ADC and Gateway, was added to CISA KEV, indicating that active exploitation is already underway. CVE-2025-6543 is a memory overflow vulnerability [CWE-119]. While the impact has been officially described as DoS, researchers believe it may come to arbitrary code execution or device takeover, as seen in similar past cases.

Both flaws only impact devices configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA (Authentication, Authorization, and Accounting) virtual servers. Both flaws are the subject of widespread national CERT advisories [1][2][3][4][5][6][7]. Greenbone provides a remote version check to detect CitrixBleed 2 and a remote version check for CVE-2025-6543. Users should patch with urgency.

A Trio of Exploitable Sitecore CMS Flaws

Three new CVEs affecting Sitecore Experience Platform can be chained to allow unauthenticated Remote Code Execution (RCE) . The flaws were disclosed with a full technical description and PoC guidance, making their exploitation highly likely. In the attack chain, CVE-2025-34509 provides initial authenticated access, while CVE-2025-34510 or CVE-2025-34511 are both post-auth RCE flaws. Attackers can first exploit hardcoded credentials to generate a valid session token, then upload a malicious “.aspx” web shell and proceed to execute arbitrary shell commands on the victim’s system. Alternatively, CVE-2025-34511 could be used to execute PowerShell commands instead of uploading a web shell.

Here are brief descriptions of each:

  • CVE-2025-34509 (CVSS 8.2): Hardcoded credentials [CWE-798] allow remote attackers to authenticate using this account to access the admin API.
  • CVE-2025-34510 (CVSS 8.8): A relative path traversal vulnerability [CWE-23] known as “Zip Slip” allows an authenticated attacker to extract malicious files from a ZIP archive into the webroot directory, which could lead to RCE via .aspx web shell.
  • CVE-2025-34511 (CVSS 8.8): An unrestricted file upload vulnerability [CWE-434] in the PowerShell Extensions module allows an attacker to upload arbitrary files, including executable scripts, to any writable location. Although CVE-2025-34511 requires the Sitecore PowerShell Extension to be installed, this is considered a common configuration.

Sitecore is a popular enterprise Content Management System (CMS) used by major global organizations across industries. While it is estimated that Sitecore represents between 0.45% and 0.86% of the global CMS market share [1][2], this user base consists of high-value targets. Greenbone is able to detect vulnerable instances of Sitecore with an active check and a remote version detection test. Patches were released in Sitecore version 10.4 and backported to earlier supported versions, allowing users to upgrade.

Bypass of CVE-2025-23120 in Veeam Backups

CVE-2025-23121 (CVSS 9.9) is a deserialization flaw [CWE-502] that allows authenticated domain users to execute arbitrary code [CWE-94] on Veeam Backup & Replication servers. The vulnerability arises from insecure data processing and is considered a bypass of a previously patched flaw, CVE-2025-23120.

No public PoC exploit is currently available. However, CVEs in Veeam Backup & Replication are often targeted by attackers. Furthermore, the vulnerability only applies to organizations using domain-joined backup servers. However, it presents a serious threat given the importance of backups in ransomware recovery. Attackers may gain valid credentials for authentication via credential theft or use password spraying to target re-used credentials.

Greenbone can remotely detect affected Veeam products and prompt patching to version 12.3.2.3617, which is strongly recommended.

Summary

June 2025 saw the emergence of at least two new wiper malware strains, threatening to impact critical infrastructure and enterprises. Widespread massive data breaches are escalating, impacting organizations and individuals as stolen data gets used for various malicious ends. This month also saw a deluge of newly discovered, critical-severity vulnerabilities in enterprise-grade products, most of which were not covered in this report. Many with PoCs or full exploit kits available within hours of their disclosure. From RoundCube and Cisco ISE to Citrix and Linux systems, high-risk digital weaknesses that demand attention are escalating the cyber war of attrition for defenders worldwide.

It’s not “unauthenticated” because the first step is to gain authentication, right?

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Joseph Lee

CVE-2025-25257: Urgent Pre-Auth RCE in FortiWeb Fabric Connector

A fresh vulnerability, CVE-2025-25257 (CVSS 9.6) in Fortinet’s FortiWeb Fabric Connector presents high risk globally. Although the CVE is still only in RESERVED status as of July 14th, 2025, it has already received a national CERT advisory from Belgium’s CERT.be and the Center for Internet Security (CIS) has also issued an alert. More alerts should follow shortly as CVE reaches PUBLISHED status.

Multiple public Proof of Concept (PoC) exploits [1][2] are available, further increasing the risk level.  Users should apply updates with urgency. Greenbone has issued a detection test for this flaw soon after its disclosure, allowing defenders to identify vulnerable systems across their networks. Let’s dig into the details of CVE-2025-25257 to find out what it’s all about.

CVE-2025-25257: Unauthenticated RCE in FortiWeb Fabric Connector

CVE-2025-25257 (CVSS 9.6) is an unauthenticated Remote Code Execution (RCE) flaw in Fortinet FortiWeb Fabric Connector with a critical impact score of CVSS 9.6. The flaw allows both SQL code and Python code to be executed on a victim’s system due to improper neutralization of HTTP headers. Shockingly, this vulnerability exists because the HTTP “Authorization:Bearer” header value is inserted into SQL queries without being sanitized [CWE-89] – which is an unforgivably poor software design. Full technical descriptions and exploits [1][2][3] have been published by watchTowr Labs and other security researchers. This means exploitation should now be considered trivial for all attackers of all skill levels.

In addition to all typical SQL Injection attacks, such as enumerating the database or modifying data, attackers can gain RCE by injecting SQL code to exploit MySQL’s INTO OUTFILE command. By writing an executable .pth file into Python’s site-packages directory (/usr/local/lib/python3.10/site-packages/ in the case of FortiWeb), it will be executed every time a Python script is run. This is because Python’s built-in initialization mechanism (site.py) is triggered during interpreter startup. FortiWeb’s web-based admin console also includes a Python-based CGI script (ml-draw.py), which can be triggered without authentication, completing the exploit-chain.

Although the vulnerability is not yet known to be exploited in the wild, its pre-auth RCE status and historical attacks against Fortinet products indicate that a low-hanging fruit such as CVE-2025-25257 is likely to be exploited soon after disclosure. FortiWeb Fabric Connector is not an edge service. However, local attackers may exploit it to modify FortiWeb WAF configurations, steal sensitive information, or install additional persistent malware.

What Is FortiWeb Fabric Connector?

FortiWeb itself is a Web Application Firewall (WAF), which can be considered an edge security device when deployed in that role. Fabric Connector is a system integration component, designed to facilitate automated coordination between FortiWeb WAF and other Fortinet products such as FortiGate and FortiManager. As other Fortinet devices generate threat data, Fabric Connector can convert that data into real-time security responses within FortiWeb. Luckily, the FortiWeb Fabric Connector is not an edge service, and therefore not typically accessible via the public Internet. However, as a WAF, FortiWeb devices are tasked with blocking malicious traffic from reaching webservers. Therefore, if attackers are able to alter its configuration, they could enable secondary attacks against web-based assets.

Mitigating CVE-2025-25257

CVE-2025-25257 affects FortiWeb versions 7.0.0 through 7.0.10, 7.2.0 through 7.2.10, 7.4.0 through 7.4.7, and 7.6.0 through 7.6.3. Users should upgrade immediately to versions 7.0.11, 7.2.11, 7.4.8 or 7.6.4 or later. If updating is not possible, Fortinet advises users to disable the FortiWeb HTTP/HTTPS administrative interface.

Summary

CVE-2025-25257 offers attackers unauthenticated RCE via Fortinet’s FortiWeb Fabric Connector HTTP API. The flaw is driven by a SQL injection vulnerability that has so far been leveraged to escalate privileges and execute Python code as well. Public PoCs and a national CERT advisory from CERT.be highlight the urgency to patch or otherwise remediate. Greenbone has issued detection tests for this flaw soon after its disclosure, allowing defenders to identify vulnerable systems across their networks.

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Markus Feilner

Massive Weaknesses in Government Data Centers, Says Bundesrechnungshof

Germany’s Bundesrechnungshof has sharply criticized the current state of cybersecurity in the federal administration. Der Spiegel quotes a document classified as confidential, which concludes that significant parts of the government’s IT infrastructure have serious security flaws and do not meet the minimum requirements of the Federal Office for Information Security (BSI).

The Bundesrechnungshof (BRH) is Germany’s supreme audit institution responsible for the federal government’s budgetary and economic oversight. It examines whether federal authorities, ministries, federal enterprises, and other public institutions are using taxpayers’ money properly, economically, and efficiently. It is independent of both the federal government and the Bundestag.

The report criticizes the lack of a central, cross-departmental information security control system. It also states that the existing security architecture must become more efficient.

Inadequate Governance  and NIS2 Preparation

Another point of criticism concerns the requirements of the NIS 2 Directive [1] [2] [3]. This introduces significant new obligations for federal authorities and KRITIS-related organizations – particularly with regard to prevention, documentation requirements, and BSI oversight. Many institutions are neither technically nor organizationally prepared for this.

The Court of Auditors welcomes the fact that the adjustment of Germany’s debt limit will allow targeted investment in cybersecurity. However, the investments are tied to the demonstrable effectiveness of the measures. In practice, this means only those who can prove their security measures lead to concrete improvements will receive future funding.

Increasing Pressure to Act

The report highlights growing pressure on public administration. The threat landscape continues to worsen, with annual damages in the hundreds of billions. The BRH is calling for a shift toward structured, data-driven, and sustainable security management.

The widespread failure is alarming. Serious weaknesses have been found in almost all data centers of German public authorities – with dramatic consequences for the security, resilience, and trustworthiness of the government’s IT infrastructure. Public authorities and KRITIS operators must take action now and introduce modern vulnerability management.

In many cases, there is not even an emergency power supply, and fewer than one in ten examined data centers meet the BSI’s minimum standards for high availability. According to the investigation, this is concerning: lack of redundancy, outdated systems, and insufficient reliability all jeopardize the functionality of critical infrastructure in the event of a crisis.

Over 180 Billion Euros in Damage Every Year

The damage is already being done: according to current figures, cyberattacks cause over 180 billion euros in damage every year in Germany. Acts of sabotage, hybrid attacks, and blackout scenarios have long been a reality – and the trend is rising.

However, the German BRH identifies many shortcomings: a lack of structured information security, cross-departmental and data-based IT risk management, and appropriate governance . Reliable information is lacking – without which it is impossible to realistically assess risk levels or progress in individual cases, let alone provide evidence.

Greenbone’s Vulnerability Management Helps

When it comes to implementing the right measures and proving their effectiveness, solutions like those offered by Greenbone come into play. Modern vulnerability management provides a decisive strategic advantage. Among other things, it provides a reliable, robust basis to support data-driven decision-making for administrators and management.

Greenbone’s OPENVAS automatically, continuously, and objectively detects, evaluates, and prioritizes vulnerabilities. This creates a reliable foundation for IT governance  structures – even in ministries, government agencies, and other public-sector enterprises. Vulnerability Management also ensures the essential transparency in times of growing accountability – thus becoming a mandatory component rather than a “nice-to-have.”

Greenbone Vulnerability Management reports contain CVSS ratings, trend analyses, and progress indicators. Authorities can use these not only for internal documentation but also to demonstrate measurable improvements to audit offices and ministries.

Equipped for NIS2

The new NIS2 directive tightens requirements for operators of critical infrastructure. It defines new responsibilities, expands BSI controls and reporting obligations, and specifies the software components to be used. As a result, more companies are dealing with the upcoming German version of the regulation.

Greenbone’s solutions actively support public authorities and KRITIS-related organizations in preparing for regulatory audits. Features such as automated vulnerability management, audit-proof reporting, and audit trails provide security, even under increasing regulatory control.

Webinars Help with Prevention – Now Is the Time to Act!

Greenbone customers receive concrete help when it comes to meeting BSI requirements in the data center, preparing for audits, and viewing vulnerability management as part of emergency preparedness. After all, prevention is always cheaper and more effective than crisis management.

The report by the German BRH is a wake-up call – and an opportunity. And because cybersecurity begins with visibility, Greenbone is the right choice. Contact us or attend our webinars – like the latest series for public authorities and KRITIS, offering in-depth information on implementing the NIS 2 Directive, data center hardening, and georedundancy, as well as on the basic structure of vulnerability control . Dates, content, and registration can be found on the website.

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Joseph Lee

LEV: Demystifying the New Vulnerability Metrics in NIST CSWP 41

In 2025, IT security teams are overwhelmed with a deluge of new security risks. The need to prioritize vulnerability remediation is an ongoing theme among IT security and risk analysts. In a haystack of tasks, finding the needles is imperative. Factors compounding this problem include a cybersecurity talent shortage, novel attack techniques, and the increasing rate of CVE (Common Vulnerabilities and Exposures) disclosure.

To meet this need for better precision and efficiency, a wave of new prioritization metrics has emerged. Not that more perspectives on risk are a bad thing, but already overwhelmed defenders find themselves in a difficult position; the choice between pushing forward or pausing to evaluate the value of new metrics.

Released by NIST (National Institute of Standards and Technology) in May 2025, the Likely Exploited Vulnerabilities (or just LEV) metric consolidates historical EPSS (Exploit Prediction Scoring System) time-series, and in-the-wild exploitation status, to compute, among other things, an aggregate risk score. In this article, we will take a dive into what LEV is and the supplemental equations released in NIST’s recent technical whitepaper (NIST CSWP 41).

The Reason Behind LEV (Likely Exploited Vulnerabilities)

LEV uses a CVE’s historical EPSS time-series to calculate a cumulative risk score representing the probability that it has ever been actively exploited. But how is this different from EPSS itself? Isn’t EPSS, a machine learning (ML) model with almost 1,500 predictive features, good enough?

Some academic criticisms have revealed that EPSS can miss critical vulnerabilities. Direct observation of historical EPSS data shows that scores can spike for a very short period of time (1-2 days), then return to a moderate or low baseline. This presents potential problems for defenders using EPSS.

For example, EPSS does not reflect how cybercriminals operate. Industry reports show that attackers exploite vulnerabilities whenever and wherever they are found, even old ones. In other words, attackers don’t say “Let’s not exploit that vulnerability because it’s too old”. Therefore, using only the most current EPSS score can hide severe risk, even those uncovered in the recent past. Defenders may solve this problem by always applying the highest EPSS score in their risk assessment. But another weakness still looms with raw EPSS scores: According to fundamental statistical theory, the accumulation of moderate probability scores should also signify high probability of an event occurring.

LEV addresses this last limitation by calculating a cumulative probability using each CVE’s historical EPSS data. LEV applies the common product-based approach for calculating cumulative probability of at least one event occurring among several independent events. As a result, CVEs which didn’t trigger alerts (even using the max EPSS) now appear as high-risk using LEV.

Mathematical Input and Symbol Reference

This section explains the input variables and mathematical symbols used in the LEV equations.

Input Reference

  A vulnerability (e.g., a CVE) All equations
d A date (without time component) All equations
d0 First date with EPSS data for v All equations
dn The analysis date (usually today) LEV, Expected Exploited, Composite Probability
dkev Date of latest KEV (Known Exploited Vulnerabilities) list update KEV Exploited
LEV (v,d0,dn) Cumulative likelihood vulnerability v is exploited from d0 to dn All equations
EPSS (v,dn) EPSS score for vulnerability v on date dn Composite Probability
KEV (v,dn) 1.0 if v is in KEV list on dn, else 0 Composite Probability
scopedcves CVEs eligible for KEV tracking (where d0 ≤ dkev) KEV Exploited
cves CVEs considered in analysis (where d0 ≤ dn)  

Symbol Reference

Symbol Name Meaning
∀ Universal quantifier “For all” / “For every” similar to a programming loop.
Π Capital Pi A “Product notation” for repeated multiplication over a sequence, similar to how ∑ means repeated addition.
∑ Capital Sigma A “Cumulative notation” for repeated addition over a sequence.
∈ Element of “Is an element of” / “belongs to”. Indicates membership in a set.

Understanding the LEV Equations

LEV is described by the “NIST Cybersecurity White Paper 41” (CSWP 41) as a lower-bound probability (conservative estimate) that a vulnerability has been exploited​. It calculates the cumulative probability that a vulnerability has been exploited at least once during a given time window. Two similar equations are provided: LEV and LEV2. The first has been optimized to reduce CPU load.

In both the LEV and LEV2 equations, each term being multiplied by the product notation Π represents the probability that no exploitation occurred on a given day within the time window. This gives the cumulative probability of no exploitation ever. Subtracting this result from 1 inverts this probability, resulting in the probability of at least one exploitation over the time window.

The two LEV equations are described below:

The Performance Optimized LEV Equation

LEV uses a CVE’s historical EPSS scores, sampled every 30 days (epss(vi, di)), along with a compensating weight when the observation window is shorter than 30 days (i.e. dn​ < 30 days.

The LEV equation proposed in NIST CSWP 41

The High Resolution LEV2 Equation

LEV2 uses the complete historical EPSS time-series rather than sampling scores every 30 days. LEV2 applies weighting by dividing by the duration of the EPSS window (30 days). LEV2 increases the temporal resolution and produces a more reliable score. Short bursts of high EPSS cannot be skipped over, as can happen with the LEV equation shown above. Each daily EPSS value is scaled by 1/30 to preserve consistent risk density across the date range.

The LEV2 equation proposed in NIST CSWP 41

The Supplemental Equations

This section introduces the supplemental equations from NIST’s LEV whitepaper, their mathematical structure and potential use-cases.

Calculating a Composite Risk Score

The supplemental Composite Probability metric described in NIST’s LEV whitepaper simply selects the strongest available signal across three exploitation indicators: EPSS, inclusion in CISA’s (Cybersecurity and Infrastructure Security Agency) KEV list and LEV.

The Composite Probability equation proposed in NIST CSWP 41

By selecting the strongest intelligence signal, Composite Probability supports vulnerability prioritization. This helps reduce blind spots where one signal may be incomplete or outdated. It is especially valuable for prioritizing remediation in large enterprise vulnerability management programs, where choosing what to fix first is a critical challenge.

Estimating Total Number of Exploited CVEs

NIST’s whitepaper also suggests a method to estimate the total number of exploited CVEs during a specified time window and how to estimate the comprehensiveness of a repository of known exploited vulnerabilities.

The Expected Exploited Calculation

The Expected Exploited metric estimates the number of exploited CVEs within a given time window by summing all LEV probabilities from a defined set of vulnerabilities. The equation simply applies the sum (∑) of all LEV probabilities for a set of CVEs to estimate the total number of likely events. Although the NIST CSWP 41 describes it as a lower bound (conservative) estimate, there is no precedent for treating this basic technique as such. In probability theory, it is a fundamental principle that the expected number of events is equal to the sum of the individual event probabilities.

The Expected Exploited equation proposed in NIST CSWP 41

The KEV Exploited Calculation

The KEV Exploited metric estimates how many vulnerabilities are missing from a KEV catalog such as CISA KEV. Quantifying the gap between Expected Exploited and KEV Exploited gives insight into potential underreporting of a KEV catalog. The equation uses the same technique as the Expected Exploited equation above: the sum of all probabilities.

The KEV Exploited equation proposed in NIST CSWP 41

The Revelations of LEV

Here are some ways to visualize the value that LEV can provide to a vulnerability management program. The supplemental Composite Probability equation is best for visualizing the contribution that LEV makes to a more comprehensive CVE risk analysis. Therefore, the observations below all use Composite Probability unless otherwise stated.

The Estimated Total Number of Exploited CVEs

When considering all CVEs since ~1980 (273,979), LEV’s Expected Exploited metric shows that 14.6% of all CVEs (39,925) are likely to have been actively exploited in the wild. This implies that the vast majority of exploitation activity is not accounted for in any known KEV list (e.g. CISA KEV included 1,228 at the time of calculation). However, Expected Exploited does not account for how many individual CVEs may be uncovered at various EPSS thresholds.

The Number of Uncovered High Risk CVEs

To assess how LEV may impact an organization’s ability to uncover risk and prioritize remediation, it is useful to consider how many CVEs are elevated to high risk status at various probability thresholds. The chart below shows how many CVEs would become visible above 50% Composite Probability.

 

Visualizing Risk Migration Using Composite Probability

The Sankey diagram compares the number of CVEs in each risk level. The left side shows maximum EPSS scores, while the right side shows LEV’s Composite Probability. Because Composite Probability is used, by rule, no CVEs can move to a lower probability bucket. The chart reveals a significant shift from the lowest risk bucket to higher risk categories, along with a increase for all other groups when using Composite Probability to estimate risk.

Sankey diagram showing the migration CVEs between risk buckets when using max EPSS and LEV’s Composite Probability metric

Limitations and Criticisms of LEV

While LEV offers valuable insights, it’s important to examine its assumptions and potential shortcomings:

  • The LEV whitepaper does not present empirical validation or comparisons with other statistical models. However, a frequentist approach, using product-based probability, is a well-established method for calculating cumulative probability for a set of independent events.
  • LEV is described as a lower-bound probability. However, there is no academic precedent claiming that the mathematical constructs in NIST CSWP 41 are conservative lower-bounds estimates.
  • LEV is not an opaque prediction system in itself, but it is based on EPSS, which is not a fully public model. While LEV addresses some potential blind-spots, it does depend on EPSS. As EPSS improves, LEV will also benefit from these improvements. For example, EPSS v4 has added malware activity and endpoint detections to its “ground truth” of exploitation in the wild. This will reduce bias towards remotely accessible network vulnerabilities.
  • Defenders should not over-rely on LEV, EPSS, or CVSS to prioritize vulnerabilities. While evidence of active exploitation is the strongest risk signal, this evidence often comes post-hoc – too late for defenders to leverage.

Summary

LEV may offer some enhancements to vulnerability prioritization by aggregating historical EPSS signals into a cumulative exploitation probability. This approach increases visibility for CVEs with a historical duration of moderate EPSS scores. Perhaps the most useful metric is the proposed Composite Probability, which will select the strongest signal from LEV, EPSS, and CISA KEV exploitation status.

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Elmar Geese

Between Trust and Responsibility: AI Security Reimagined

Artificial intelligence (AI), the security of AI systems and the use of AI in security are no longer a thing of the future – they are our present. And they have long been an integral part of our daily work to improve IT security. At the same time, they bring with them a new quality of risks that we in the security industry must take very seriously.

From Bach to Artificial Intelligence: a Journey Through Time

My first encounter with AI was a long time ago. In 1979, a friend of mine spent every spare minute reading a thick white book called “Gödel, Escher, Bach”. As a musician, I was initially only interested in the aspect relating to Johann Sebastian Bach. Unfortunately, it didn’t help me much in my attempts to play “The Well-Tempered Clavier” and its fugues. But I did learn about AI.

In the book, author Douglas R. Hofstadter describes how complex, intelligent behavior can arise from astonishingly simple systems. The idea: self-referential loop structures that create levels of meaning – whether in logical proofs, drawings, or musical compositions.

Bach’s fugues repeatedly contain melodies that contain themselves and are played simultaneously in variations, creating a new musical level in which the individual melody seems to disappear again and again, but is actually always there. So, it’s a bit like what we experience with large language models and generative AI: the individual disappears into a new, larger whole.

When complex structures generate meaning at a higher level and we can then map this using digital tools, we call the whole thing artificial intelligence. Hofstadter refers to these as rule-based systems. Our current AI systems do this in the form of neural networks, which produce seemingly “intelligent” outputs through the interaction of billions of parameters. Similar to flocks of birds, ant colonies, or the stock market, emergent behavior arises: we use systems that we no longer fully understand, but whose results seem plausible and useful enough to us to use them.

The Balancing Act Between Usefulness and Control

After decades of development, the use of artificial intelligence has become commonplace in recent years. Whether we have already largely exhausted its actual capabilities or are still at the very beginning of an exponential curve remains to be seen. We are on the critical path from simple dialogue functions to semi-autonomous or even autonomous systems. Here, technical efficiency (e.g., response time or loss tolerance) naturally conflicts with human qualities such as judgment, responsibility, and the ability to make reasoned decisions. And because we are making AI systems increasingly powerful, the question becomes more urgent: How secure, vulnerable, and trustworthy are they really?

Trust

Just as with our partners, colleagues, and people in general, we cannot fully understand the internal processes of AI. This not only makes AI difficult to verify, but also particularly vulnerable to targeted manipulation, whether through adversarial attacks or subtle input distortions. But not using AI is obviously not a solution either. There is no way around it: we have to deal with it. We can only establish trustworthy tools and processes that protect us well enough.

It is in the nature of things that we have to be content with statistical probabilities instead of provable truths that we can understand. In practice, this usually works well – but not always. Where trust is based on habit rather than understanding, there is no basis for control in an emergency. This can lead to misunderstandings about what AI can and cannot do. Serious proposals are then made to simply let AI control nuclear power plants due to a lack of available specialist personnel. We’d rather not do that.

The potential technical protection of AI systems is probably more advanced than protection against such ideas. What is the current state of technical protection for AI systems? Here are a few answers:

  1. AI systems are just software and hardware. Classic IT security architecture remains relevant, even for AI. On the one hand, this is somewhat alarming, but on the other hand, it means we are at least well equipped to test security.
  2. There are initial AI-specific protection mechanisms that can at least mitigate simple things like prompt injection. Content filtering and moderation systems can protect against toxic or unwanted output.
  3. AI systems can be monitored using a combination of statistical and rule-based checks.
  4. Smaller models such as Small Language Models (SLMs) allow us to reduce the attack surface. Large models such as ChatGPT, Claude, or Gemini are powerful, but particularly difficult to control and test. They are also very large, practically impossible to transport, extremely energy-intensive, and very expensive to maintain. However, there are increasingly better and smarter solutions available.

The more specifically I can define a task, the less I need a general-purpose LLM – and the better an SLM can be used: SLMs are easier to oversee, more transparent to operate, can be hardened locally, and secured more efficiently. These are not panaceas, but important building blocks for responsible AI use. One might ask: If this AI can do so much, why can’t it simply protect itself? Why don’t we build security AI for AI?

Why AI Cannot Simply Secure Itself

As early as 1937, Alan Turing published “On Computable Numbers”, a mathematical description of what he called a universal machine, an abstraction that can, in principle, solve any mathematical problem presented to it in symbolic form. However, the decision problem revealed the limits of machine thinking right from the start. Turing proved that there is no general method for completely predicting the behavior of arbitrary programs. This also applies equally, if not more, to today’s AI.

In any sufficiently powerful formal system, there are true statements that cannot be proven. This brings us to Gödel and his incompleteness theorem. AI can and will become increasingly powerful, even if it will never be completely predictable or understandable. Of course, this does not prevent us from using AI systems.

However, superintelligence will not exist in the foreseeable future. We cannot build AI that is guaranteed to be error-free, and AI cannot do so either. It is interesting and sometimes fascinating, but it is neither a panacea nor a mystery. Our task, therefore, is not to eliminate risks but to identify them, limit them, and bear them responsibly. Pragmatism is called for: we must seize the opportunities while managing the risks.

Optimists say: We can do it.

Pessimists say: It will be a disaster.

Pragmatists say: We have to get through it.

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Markus Feilner

TÜV Study on Cyber Security: German Companies Still Under Pressure

Companies operate under a “false sense of security,” warn the BSI and TÜV. This may sound surprising given the persistent threats. However, it is backed up by a recent study on cyber security in companies.

Many companies underestimate the situation, overestimate their own capabilities, and fail to take sufficient protective measures. These and other findings were made by the German Technical Inspection Association (TÜV) and the German Federal Office for Information Security (BSI). Only half of those surveyed were aware of NIS-2, which is alarming given that 29,000 additional companies will be affected by it. At the same time, over 90 percent consider their own security to be good or very good. Shockingly, for a quarter, IT security only plays a minor role.

BSI Management Is Concerned

The head of the BSI, Claudia Plattner, is concerned and warns that Germany still faces significant challenges ahead. Plattner also refers to the EU’s Cyber Resilience Act, which prescribes minimum requirements for networked products in Europe. TÜV notes that while awareness of the problem has grown, many companies still are not sufficiently prepared.

Dr. Michael Fübi, President of the TÜV Association, and Claudia Plattner, BSI President, at the presentation of the study, Source: BSI

Four Percent More Victims of Cyber Attacks

The 58-page study contains numerous worrying findings. The number of cyberattacks on companies increased be four percent over the last year – now impacting roughly one in seven. In almost all cases (84 percent) the intrusion was carried out via phishing. More and more threat actors utilise AI in their attacks, while it is hardly used by defenders (51 percent vs. 10 percent). Seven out of ten respondents consider security standards to be important, but only 20 percent put them into practice.

“Cybersecurity in German companies” – the TÜV Cybersecurity Study 2025

The TÜV Association is therefore calling on politicians to prioritize cybersecurity and include it in the overarching security strategy, as well as to clarify responsibilities more clearly. NIS2 and CRA must be “launched swiftly” despite all the delays to date.

TÜV’s Recommendations for Business

According to TÜV, companies should take threats seriously and carry out qualified risk analyses regularly. A cyber strategy is essential, as are security guidelines with measurable objectives, clearly assigned responsibilities, and concrete action plans.

Differences Between Large and Small Companies

The study reveals a striking difference based on company size. While 95% of companies with more than 250 employees give great importance to IT security, only two thirds of companies with up to 50 employees do so. Only in terms of self-assessment do large and small companies agree: over 90% consider themselves to be well protected, regardless of company size. However, almost half of large companies (41%) are aware of the high risk in the supply chain, while only 21% of small companies share this assessment. 78% of companies with fewer than 50 employees also do not believe that the supply chain poses a risk of cyberattack.

Origin Unknown

Although most companies fear criminal or state-sponsored attackers, internal actors are perceived as less of a threat. Only 9 percent were able to attribute attacks to a regional source, with 6 percent of the incidences coming from China, according to the more than 500 respondents.

Investment in Cyber Security

27% of companies also increased their IT security budget over the last year, while 15% hired additional experts – a slightly lower ratio than in the previous year. Around 20 percent of companies try to increase security by either using increasing or reducing the use of cloud services. Pentesting and emergency drills are also at the bottom of the list at around 25% each.

The majority of investments focus on hardware updates, new cybersecurity software, and measures for networked systems – exactly the areas covered by Greenbone’s specialized products.

Conclusion: Unspecific Threat, Known Methods, Lack of Security Discipline

Looking at the results of the study, the conclusion will be evident that, although it is by no means clear where the attacks are coming from, the successful methods of attack seem clear. There is also an asymmetry in the use of technology, as the example of AI shows.

The fact that almost 80 percent of respondents admit to only implementing common security standards to a limited extent is a clear warning sign – for BSI, Politicians, and security experts alike. Unsurprisingly, the TÜV association is calling on the German government to advance cyber security, and implement regulations quickly. After all, this is what the majority of respondents want.

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Joseph Lee

Threat Report May 2025: Hack, Rinse, Repeat

May 2025 was a volcanic month for cybersecurity news, including several large breaches and new critical severity vulnerabilities. The Greenbone blog has already covered some major events, such as new actively exploited vulnerabilities in SAP Netweaver, Commvault Command Center and Ivanti EPMM. In total 4,014 new vulnerabilities were added to MITRE’s CVE (Common Vulnerabilities and Exposures) program. Greenbone added over 2,500 vulnerability tests to the Enterprise Feed, many capable of detecting multiple CVEs.

In this threat report for May 2025, we will round up some of the riskiest new CVEs disclosed this month, review a nation-state backed cyber campaign impacting tech companies around the world, and review how AI is poised to escalate cyber risk with intelligent automation at all stages of the Cyber Kill Chain.

The Inevitable AI-Enabled Attack Cycle: Hack, Rinse, Repeat

AI is now a force multiplier in the cyber attack lifecycle. Threat actors are leveraging AI in two fundamental ways; expediting the conversion of public vulnerability knowledge into exploit tools, and building more convincing social engineering content. Researchers have proposed a long list of additional capabilities that AI can further optimize, including automation of initial access attacks and command-and-control (C2) operations.

Even without AI, skilled human hackers can exfiltrate sensitive information within minutes of initial access. If significant vulnerabilities exist on the LAN side of a victim’s network, manual deployment of ransomware is trivial. In 2017, WannaCry demonstrated that ransomware attacks can be automated and wormable, i.e., capable of spreading between systems autonomously.

According to Norton’s latest Gen Threat Report, data-theft has increased 186% in Q1 2025. As discussed last month, data-theft-related class action filings have risen more than 1,265% over six years. When a victim’s cyber hygiene is non-compliant, multi-million dollar settlements are the norm. The top 10 data-breach class action settlements in 2023 totaled over 515 million dollars; the largest was a 350 million dollar settlement involving T-Mobile. This stolen data is often sold on the dark web, becoming fuel for subsequent cyber attacks. We should expect AI to reach full autonomy at all stages of the Cyber Kill Chain in the near future, resulting in a fully autonomous vicious cycle of exploitation; hack, rinse, repeat.

Russian GRU-Backed Espionage Campaign Hits Global Tech and Logistic Firms

CISA (Cybersecurity and Infrastructure Security Agency) and defense entities from nine other countries have warned of a cyber espionage-oriented campaign. The operation is being conducted by the Russian General Staff Main Intelligence Directorate (GRU), specifically the 85th Main Special Service Center (85th GTsSS), military unit 26165. The group is tracked under several aliases including the well-known FancyBear and APT28.

The full report outlines detailed Tactics, Techniques and Procedures (TTPs) leveraged in the campaign, which includes reconnaissance [TA0043], credential brute forcing [T1110.003], spearphishing to attain credentials and deliver malware [T1566], exploiting trust relationships to gain access [T1199], proxying attacks through compromised devices [T1665] and exploiting known software vulnerabilities – both for initial access [T1190] and privilege escalation [T1068]. The sheer diversity of attack techniques indicates a highly sophisticated threat.

The campaign targets a wide range of small office/home office (SOHO) devices, Microsoft Outlook, RoundCube Webmail and WinRAR as well as undisclosed CVEs in other internet-facing infrastructure – including corporate VPNs and SQL injection flaws. Greenbone includes detection tests for all CVEs referenced in the report. Those CVEs include:

  • CVE-2023-23397 (CVSS 9.8): A privilege escalation vulnerability in Microsoft Outlook that leverages replay of captured Net-NTLMv2 hashes.
  • CVE-2020-12641 (CVSS 9.8): Allows attackers to execute arbitrary code via shell metacharacters in a Roundcube Webmail configuration setting for `im_convert_path` or `im_identify_path`.
  • CVE-2020-35730 (CVSS 5.0): An XSS flaw in Roundcube Webmail via a plain text email message, containing a JavaScript link reference.
  • CVE-2021-44026 (CVSS 9.8): An SQL injection flaw in Roundcube via search or search_params.
  • CVE-2023-38831 (CVSS 7.8): Allows attackers to execute arbitrary code when a user attempts to view a benign file within a ZIP archive.

DragonForce Ransomware Spreads its Wings

Emerging in mid-2023, DragonForce transitioned from a hacktivist collective into a financially motivated Ransomware-as-a-Service (RaaS) operation. Fast forward to 2025, and DragonForce has established itself as an apex threat in the ransomware ecosystem.

DragonForce ransomware attacks impacted the following countries:

  • United States – 43 confirmed incidents
  • United Kingdom – including recent May 2025 breaches of Marks & Spencer, Co-op and Harrods
  • Saudi Arabia – a data leak from a major Riyadh construction firm
  • Australia – e.g., Yakult Australia
  • Singapore – Coca-Cola operations
  • Palau – a government breach in March 2024
  • Canada – among the top five most attacked nations
  • India – has faced increased targeting, particularly in the past month

Campaigns have included exploitation of SimpleHelp remote monitoring and management (RMM) [1], Confluence Server and Data Center [2], Log4Shell (aka Log4J), Microsoft Windows vulnerabilities, as well as various flaws in Ivanti products [3]. Greenbone provides multiple active check and version detection tests for all CVEs identified in DragonForce campaigns.

DragonForce has been observed exploiting:

In line with the attack trajectory of other prominent ransomware actors, DragonForce is known to use other techniques in addition to breaching public-facing vulnerabilities such as phishing emails, credential theft, brute-force, and credential stuffing attacks on exposed services and remote management (RMM) tools like AnyDesk, Atera, and TeamViewer, for persistence and lateral movement. Therefore, organizations need comprehensive cybersecurity programs that include user awareness training to prevent social engineering attacks and regular penetration testing to simulate real-world adversarial activity.

CVE-2025-32756: Stack-Based Buffer Overflow Vulnerability in Multiple Fortinet Products

CVE-2025-32756 (CVSS 9.8), published on May 13, 2025, is a critical severity stack-based buffer overflow vulnerability [CWE-12] affecting multiple Fortinet products. It allows remote, unauthenticated attackers to execute arbitrary code via a crafted HTTP cookie. The flaw is being actively exploited in the wild – primarily against FortiVoice systems – and is linked to attacks involving malware deployment, credential theft using cron job, and network reconnaissance. Proof-of-concept details are publicly available, and a full technical analysis has been published increasing the risk factor.

Fortinet flaws have a historically high conversion rate for use in ransomware attacks. A total of 18 vulnerabilities in Fortinet products have been added to CISA Known Exploited Vulnerabilities (KEV) list since late 2021 – 11 of these are known to be leveraged by ransomware operators. In addition to CISA, several other national CERT entities have issued alerts, including CERT-EU, the Centre for Cybersecurity Belgium (CCB), and Germany’s CERT-BUND.

The root cause is a missing length check in the `cookieval_unwrap()` function of libhttputil.so. A malicious AuthHash cookie can induce memory corruption to control the return memory address, allowing an attacker to hijack execution flow at the process level. Greenbone Enterprise Feed provides a vulnerability test to detect affected products and almost 1,000 other tests for detecting other vulnerabilities in Fortinet products.

CVE-2025-32756 affects dozens of firmware versions across multiple FortiNet products, including:

  • FortiVoice (6.4.0 – 7.2.0)
  • FortiMail (7.0.0 – 7.6.2)
  • FortiNDR (1.1 – 7.6.0)
  • FortiRecorder (6.4.0 – 7.2.3)
  • all versions of FortiCamera 1.1 and 2.0 as well as 2.1.0 – 2.1.3

Fortinet advises upgrading to the latest fixed versions immediately. If patching is not feasible, users should disable the HTTP/HTTPS administrative interface to prevent successful attacks.

Trio of SysAid Flaws Now Have CVEs and Public PoC

In May, three critical-severity vulnerabilities were disclosed affecting on-premises SysAid IT Service Management (ITSM) platform. These flaws can be chained, allowing unauthenticated Remote Code Execution (RCE). Full technical details and Proof-of-Concept (PoC) were published by watchTowr. Also, considering that SysAid vulnerabilities have been targeted by ransomware operators in the past, these flaws are especially high risk.

CVE-2025-2775, CVE-2025-2776, and CVE-2025-2777 (each CVSS 9.3) are unauthenticated XML External Entity (XXE) [CWE-611] vulnerabilities, found in the Checkin, Server URL and lshw functions respectively. All allow admin account takeover and arbitrary file read on the victim’s system. SysAid On-Prem versions ≤ 23.3.40 are affected. Notably, the flaws were patched by the vendor in March, but CVE IDs were not reserved or issued. This type of scenario contributes to a less transparent threat landscape for software users, reducing visibility and complicating operational vulnerability management. Greenbone offers detection tests for all aforementioned CVEs.

SysAid has a global presence of over 10,000 customers across 140 countries, including organizations such as Coca-Cola, Panasonic, Adobe, and LG. While it holds a smaller share of the ITSM market compared to larger competitors like ServiceNow or Jira Service Management, it remains a popular solution for mid-sized businesses.

A CVSS 10 in Cisco IOS XE Wireless Controller

CVE-2025-20188 is a new critical-severity (CVSS 10) vulnerability disclosed in May 2025. It affects Cisco’s flagship platform, the Catalyst 9800 Series. Although not known to be actively exploited yet, a full technical walkthrough is now available, which will provide less sophisticated threat actors with a head start.

The root cause of the vulnerability is a hard-coded JSON Web Token (JWT) which could allow the attacker to upload files, perform path traversal, and execute arbitrary commands with root privileges via specially crafted HTTP request. Specifically, a hardcoded fallback secret – the string `notfound` – is used to verify the authenticity of a JWT if `/tmp/nginx_jwt_key` is not present.

Although this key file may be generated at certain times, such as when an administrator logs into the management console, it may not be present at certain times, such as immediately after a device reboot or service start.

Crucially, the flaw does not affect all HTTP endpoints – it is limited to the Out-of-Band Access Point (AP) Image Download feature of Cisco IOS XE Software for WLAN Controllers (WLCs). While Cisco’s advisory claims this service is not enabled by default, Horizon.ai researchers found that it was. Therefore, while there are several conditions affecting the exploitability of CVE-2025-20188, if those conditions are present, exploitation is trivial – and likely affects many organizations.

Cisco has released an advisory which recommends that affected users either upgrade to the patched version, or disable the Out-of-Band AP Image Download feature. Greenbone Enterprise Feed includes a version detection test for identifying affected devices and verifying patch level.

Summary

May 2025 delivered a surge of critical vulnerabilities, major breaches and escalating nation-state activity. It’s important to keep in mind that AI-enhanced attack cycles are destined to become a reality – the chaotic and urgent cybersecurity landscape shows no sign of easing any time soon.

New actively exploited flaws in Cisco, Fortinet, and SysAid products force organizations to maintain vigilant, continuous detection efforts, followed by prioritization and mitigation.

Greenbone’s Enterprise coverage helps security teams see vulnerabilities that threat actors can exploit to stay ahead in a fast-moving threat landscape.

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Greenbone AG

Greenbone Audits for Compliance with the CIS Windows 11 Enterprise Benchmark”

Microsoft Windows remains the most widely used desktop operating system in enterprise environments – and also one of the most targeted by threat actors. Insecure configurations are a leading source of security breaches [1][2][3], often exploited to gain initial access [TA0001], escalate privileges [TA0004], steal credentials [TA0006], establish persistent access [TA0003], and move laterally within a network [TA0008]. Many national cybersecurity agencies continue to advocate strongly for organizations to enact policies to strengthen operating system (OS) baseline configurations [4][5][6][7][8].

Securing Windows 11 systems requires more than just patching known vulnerabilities. IT operations should start by deploying security hardened baseline images of Windows and periodically verify their configuration. This means adjusting many hidden or often overlooked settings of Microsoft Windows while disabling some features altogether. Hardened security controls include enforcing strong password and account lockout policies, disabling unnecessary system services like Remote Registry, applying application control rules via AppLocker, configuring advanced audit policies to monitor system activity and more.

Aligning with these enterprise IT cybersecurity goals, Greenbone is proud to announce the addition of CIS Microsoft Windows 11 Enterprise Benchmark v3.0.0 Level 1 (L1) auditing to our compliance capabilities. This latest enhancement allows our Enterprise feed customers to verify their Windows 11 configurations against the CIS compliance standard and adds to Greenbone’s growing arsenal of CIS compliance policies including Google Chrome, Apache, IIS, NGINX, MongoDB, Oracle, PostgreSQL, Windows, Linux and Docker [1][2]. Read on to find out more about Greenbone’s latest IT security detection capabilities.

Greenbone Adds CIS Microsoft Windows 11 Enterprise Benchmark

The CIS Microsoft Windows 11 Enterprise Benchmark v3.0.0 L1 is now available in the Greenbone Enterprise Feed. This benchmark defines a comprehensive set of security configurations – from Group Policy and registry hardening to built-in feature restrictions – designed to lock down Windows 11 Enterprise in line with industry best practices. With this new addition, Greenbone makes it easier to identify Microsoft Windows misconfigurations before attackers can exploit them.

Our Enterprise vulnerability feed leverages compliance policies to execute tests to verify each automatable CIS L1 requirement. These tests are grouped into scan configurations, allowing security teams to launch targeted assessments across their Windows 11 fleet. Whether aligning with internal security mandates or regulatory frameworks, Greenbone’s audit will confirm your Windows 11 Enterprise settings, ensuring that systems are locked down and that deprecated or risky features are disabled.

Windows Security Is Paramount

Microsoft Windows plays a prominent role in enterprise IT environments, serving as the backbone for endpoints, servers and domain infrastructure. But this ubiquity also makes it a prime target. Insecure Windows configurations can open the door to Remote Code Execution (RCE), credential theft and privilege escalation. A serious cyber breach can result in full domain compromise, ransomware attacks, loss of customer confidence, regulatory fines and even high cost legal action such as class action lawsuits when user data is leaked.

In recent years, national cybersecurity agencies – including Germany’s BSI [9], the U.S. Cybersecurity and Infrastructure Security Agency (CISA) [10] and the Canadian Centre for Cyber Security [11] among others [12][13] – have issued alerts emphasizing the need to harden OS security configurations and disable legacy features that attackers routinely exploit. The increasing frequency and sophistication of adversarial threat actors further underscores the need for proactive Windows security.

Misconfigurations in Windows can have a cascading impact, compromising both the local system and the wider network. That’s why hardening efforts must go beyond vulnerability patching to include robust configuration management. Greenbone’s new CIS Windows 11 Enterprise compliance policy gives defenders the tools they need to strengthen resilience against many critical IT security weaknesses.

How Does the CIS Windows 11 Benchmark Improve Cybersecurity?

The CIS Microsoft Windows 11 Enterprise Benchmark offers a structured approach to securing Microsoft Windows endpoints. It defines configuration settings that could be used for unauthorized access, privilege abuse and system compromise. The benchmark audits a wide range of policies including account security, system services, network configurations, application controls and administrative templates to reduce attack surface and improve system integrity.

The major sections of the CIS Windows 11 benchmark are:

  • Account Policies: Defines policies for password complexity, history, expiration and account lockout thresholds. These settings help enforce strong authentication hygiene and limit brute-force attacks.
  • Local Policies: Focuses on enforcing a wide array of local access controls and system behavior. It covers audit settings, user rights assignments (like who can log in locally or shut down the system) and security options (like guest account status, access tokens, network access, device drivers, firmware options and cryptography requirements) and more.
  • System Services: Reduces attack surface by limiting active system components. Recommends disabling or configuring Windows services that may be unnecessary or expose the system to risk (e.g., Remote Registry, FTP, Bluetooth, OpenSSH, Geolocation service and more).
  • Windows Defender Firewall with Advanced Security: Covers firewall configurations for domain, private and public profiles. Includes rules for logging, connection restrictions and blocking unsolicited inbound traffic to enforce network segmentation and traffic control.
  • Advanced Audit Policy Configuration: Provides granular auditing settings across categories like logon events, object access and policy changes to enhance visibility and compliance.
  • Administrative Templates (Computer): Covers Group Policy settings at the computer level, including UI restrictions, legacy protocol controls, SMB hardening, UAC behavior and device configuration.
  • Administrative Templates (User): Focuses on user-level policies affecting personalization, privacy, desktop behavior, Windows components, telemetry, cloud content, search and Microsoft Store access.

Greenbone Is a CIS Consortium Member

As a member of the CIS consortium, Greenbone is committed to adding additional scan configurations to attest CIS Benchmarks. All our CIS Benchmarks policies are aligned with CIS hardening guidelines and certified by CIS, ensuring maximum security for system audits. Greenbone also has a dedicated compliance view for the Greenbone Security Assistant (GSA) web-interface, to streamline the assessment process for organizations.

Summary

Securing Microsoft Windows 11 Enterprise requires more than patching vulnerabilities – it demands a disciplined approach to configuration management based on proven best practices. By hardening hidden system settings and disabling unnecessary features, security teams can prevent exploitation paths commonly used by attackers to deploy ransomware, exfiltrate data or establish persistence.

With added support for the CIS Microsoft Windows 11 Enterprise Benchmark v3.0.0, Greenbone strengthens its position as a leader in proactive cybersecurity, offering enterprises the tools they need to reduce risk, demonstrate compliance and stay resilient in an increasingly hostile digital landscape. Enterprise Feed subscribers can now audit and verify their Windows 11 configurations with precision and confidence

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Markus Feilner

Dwell time: Attackers Are Striking Faster and Disguising Themselves Better

Security experts are observing a worrying trend: the time to exploit (TTE), i.e. the time between a security vulnerability becoming known and being exploited by malicious actors, has been falling dramatically in recent times.

At the same time, attackers are becoming increasingly skilled at concealing their presence in a successfully hacked network. Experts refer to the time it takes to establish a foothold and then gain unauthorized access to company resources before being detected (and removed) as “dwell time”. The shorter this time, the better for those under attack. Even the most talented hacker needs time and can cause more (permanent) damage the longer they remain undetected and unobserved.

The Enemy Is Listening – and May Already Be There

Alarmingly, dwell time is increasingly reaching months or even years, as was the case with Sony and the US Office for Personal Management. There, attackers were able to operate undisturbed for more than twelve months. As a result, more than 10 terabytes of data were stolen from the Japanese technology group.

The fear of hidden intruders is great; after all, no one can say with certainty whether a malicious listener is already on their own network. It happens. In the 2015 Bundestag hack, for example, it was not the Bundestag’s own monitoring system that informed the German authorities about strange activities by third parties (Russian APT hacker groups) on the Bundestag network, but a “friendly” intelligence service. How long and how many actors had already been active in the network at that point remained unclear. The only thing that was clear was that there was more than one, and that the friendly intelligence services had been watching for some time.

Detection, Prevention and Response Increasingly Critical

This makes it more important to ensure that attackers do not gain access to the system in the first place. But this is becoming increasingly difficult: as reported by experts at Google’s Mandiant, among others, the response time available to companies and software operators between the discovery of a vulnerability and its exploitation has fallen rapidly in recent years, from 63 days in 2018 to just over a month in recent years.

Less and Less Time to Respond

In 2023, administrators had an average of only five days to detect and close vulnerabilities. Today it is already less than three days.

But that’s not all. In the past, security vulnerabilities were often exploited after patches became available, i.e., after experienced administrators had already secured their systems and installed the latest patches. These so-called “N-day vulnerabilities” should not really be a problem, as fixes are available.

Improved Discipline with Side Effects: Attackers Learn

Unfortunately, in the past, discipline (and awareness) was not as strong in many companies, and the issue was neglected, inadvertently contributing to the spread of automated attack methods such as worms and viruses. But there is good news here too: in 2022, attacks via N-day vulnerabilities still accounted for 38% of all attacks, but by 2023 this figure will fall to just 30%.

At first glance, this sounds good because administrators can find and fix known vulnerabilities for which patches are available more quickly and effectively. After years of poor discipline and a lack of update and patch strategies, the major and successful ransomware incidents have certainly also helped to convey the scope and importance of proper vulnerability management to the majority of those responsible.

Two-thirds Are now Zero-days

But there is also a downside to these figures: more than two-thirds of all attacks are now based on zero-day vulnerabilities, i.e., security gaps for which there is no patch yet – in 2023, this figure was as high as 70%. Criminal groups and attackers have reacted, learned and professionalized, automated and greatly accelerated their activities.

Without automation and standardization of processes, without modern, well-maintained and controlled open-source software, administrators can hardly keep up with developments. Who can claim to be able to respond to a new threat within three days?

Powerless? Not with Greenbone

When attackers can respond faster to new, previously unknown vulnerabilities and have also learned to hide themselves better, there can only be one answer: the use of professional vulnerability management. Greenbone solutions allow you to test your network automatically. Reports on the success of measures give administrators a quick overview of the current security status of your company.

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