With the help of Greenbone products, known vulnerabilities in an IT infrastructure can be detected and subsequently eliminated. Assessing the severity of a vulnerability is an essential tool for planning and prioritizing subsequent remediation actions. CVSS provides such an assessment according to a metrics system. Since 2021, Greenbone’s current solutions also support CVSS versions 3.0 and 3.1, and at the same time, Greenbone started to provide all vulnerability tests for which a respective rating is available with it. As of October 2021, this work is now complete and there is – as far as possible – full CVSSv3x coverage in the Greenbone feeds.

Helpful Severity Metrics

Every cyber attack needs a vulnerability to be successful. Most vulnerabilities, namely 999 out of 1,000, have already been known for more than a year and can therefore be proactively detected and eliminated. For detection, a Greenbone vulnerability scanner is used, which finds the known vulnerabilities in an IT infrastructure.

If vulnerabilities are discovered, they can subsequently be eliminated using a wide variety of measures. The most urgent vulnerabilities to be eliminated are those that pose a critical risk to the IT system. Prioritization is required for selecting the measures and the order.

The severity is an essential tool for prioritization. However, we will take a closer look at how vulnerabilities are assigned a severity level in the first place and how it is calculated.

How Severity Ratings Are Created

In the past, different organizations and security research teams discovered and reported vulnerabilities at the same time and named them with different names. This resulted in the same vulnerability being reported by, for example, multiple scanners under different names, making communication and comparison of results difficult.

To address this, MITRE founded the Common Vulnerabilities and Exposures (CVE) project. Each vulnerability was given a unique identifier as a central reference, consisting of the year of publication and a simple number. The CVE database is used to link vulnerability databases with other systems and to allow comparison of security tools and services.

CVEs thus do not contain any detailed, technical information or information regarding the risks, effects or elimination of a vulnerability. In some cases, the version in which the vulnerability was removed is stored.

Further information about a vulnerability can be found in the National Vulnerability Database (NVD). The NVD – a U.S. government vulnerability management data repository – supplements CVEs with information regarding remediation, potential impact, affected products, and also the severity of a vulnerability.

How is the Severity of a Vulnerability Calculated?

The Common Vulnerability Scoring System (CVSS) was developed to enable the assessment of vulnerabilities. CVSS is an industry standard for describing the severity of security risks in IT systems. It was developed by the CVSS Special Interest Group (CVSS-SIG) of the Forum of Incident Response and Security Teams (FIRST). The latest CVSS version is 3.1.

The CVSS score evaluates vulnerabilities according to various criteria, so-called “metrics”: base-score metrics, temporal-score metrics and environmental-score metrics.

• Base-score metrics: base-score metrics represent the basic characteristics of a vulnerability that are independent of time and the IT environment: how well can the vulnerability be exploited and what is the impact?
• Temporal-score metrics: temporal-score metrics represent characteristics that can change over time but are the same in different IT environments. For example, the deployment of a patch by the deploying organization would lower the score.
• Environmental-score metrics: environmental-score metrics represent the characteristics that apply to a specific IT environment. Relevant here are how well the affected organization can intercept successful attacks or what status a particular vulnerable system has within the IT infrastructure.

Since, in general, only the base score metrics are meaningful and can be determined permanently, only these are usually published and used.

CVSSv3.0/v3.1 Support Since GOS 21.04

Since GOS 21.04, which was released in April 2021, versions 3.0 and 3.1 of CVSS are also supported. Although some CVEs – and thus also the associated vulnerability tests – still contain version 2 CVSS data, this mainly affects older CVEs from the year 2015 and earlier, for which no CVSSv3.0/v3.1 score is yet stored in the NVD.

Let’s look at the biggest changes that versions 3.0 and 3.1 include.

Compared to CVSS version 2.0, version 3.0 retains the main groups of metrics – base, temporal, and environmental – but adds new criteria. For example, the metrics “Scope (S)”, which indicates whether a vulnerability can also affect other components of an IT network, and “User Interaction (UI)”.

Some existing criteria have also been replaced by newer ones: “Authentication (Au)” has become “Privileges Required (PR)”. It is no longer measured how often attackers have to authenticate themselves to a system, but what level of access is required for a successful attack.

In addition, the severity levels were subdivided more finely. In version 2.0, the values from 0 to 10 were divided into three severity levels: “Low” (0.0 – 3.9), “Medium” (4.9 – 6.9) and “High” (7.0 – 10.0). Since version 3.0, there are five levels: “None” (0.0), “Low” (0.1 – 3.9), “Medium” (4.0 – 6.9), “High” (7.0 – 8.9) and “Critical” (9.0 – 10.0).

CVSS version 3.1 did not bring any changes to the metrics or the calculation formulas. Instead, the focus was on emphasizing that CVSS measures the severity of a vulnerability rather than the risk it poses. A common mistake was to view the CVSS score as the sole characteristic of a vulnerability’s risk, rather than performing a fully comprehensive risk assessment.

In the course of this, the definitions of the metrics were formulated more clearly and the glossary was expanded.

Full CVSSv3.0/v3.1 Coverage in the Feed

With CVSSv3.0/v3.1 support in April 2021, Greenbone began updating all vulnerability tests assigned a CVSSv3.0/v3.1 score in the NVD to include a CVSSv3.0/v3.1 score.

This was done in daily stages of 500 – 600 vulnerability tests. The update and conversion were thoroughly reviewed and tested. Since October 2021, this work has now been completed. Thus, there is – as far as possible – full CVSSv3x coverage in the Greenbone feeds.

Since 2021-04-30, the latest GOS version – version 21.04 – is available and, as always, it brings a lot of new features and improvements! What exactly? Get an overview of all important changes with GOS 21.04 here!

New Hardware Models for Our Midrange Class Available

A new hardware generation has been introduced for the Midrange Class hardware appliances, which are used for medium-sized companies or for branch offices of large, distributed companies.

The new hardware now uses SSD-type hard disks instead of HDD, which are 10 times faster, quieter and lighter. There is also more hard disk space available. The RAM has also been improved. It is now DDR4 instead of DDR3, which makes it significantly faster with a higher clock rate (3200 MHz). Furthermore, twice to four times as much main memory is available than before. In addition, a new, faster CPU of the latest generation has been installed. The ports of the appliances also change: instead of 6 ports GbE-Base-TX and 2 ports 1 GbE SFP, there are now 8 ports GbE-Base-TX and 2 ports 10 GbE SFP+.

The model names remain unchanged.

Boreas Alive Scanner now as Standard

The Boreas Alive Scanner is a host alive scanner that identifies the active hosts in a target network. It was introduced with GOS 20.08, but was previously optional. With GOS 21.04, the Boreas Alive Scanner became standard.

Compared to the Nmap port scanner, which was previously used by default, the Boreas Alive Scanner is not limited in terms of the maximum number of alive scans performed simultaneously and is therefore faster.

The Boreas Alive Scanner significantly reduces scanning time for large networks with a small percentage of reachable hosts. This also makes it possible to get the first scan results faster, regardless of the percentage of alive hosts in the network.

Clearer Results Thanks to New Report Formats

Two additional report formats are now available for exporting reports, replacing the previous standard report formats: Vulnerability Report PDF and Vulnerability Report HTML. The report formats are clearly structured and easy to understand. Specific information relevant to the target group can be quickly identified and understood.

The report formats provide a basis for user-defined reports, which are planned for future GOS versions.

New Network Backend for a more Stable Connection

With GOS 21.04, the network configuration backend in GOS has been improved by introducing the gnm networking mode. This prevents connection losses in certain network configurations as well as connection problems with SSH sessions. In addition, the GSM no longer needs to be restarted after certain network settings have been changed.

New Hypervisors for Our Virtual Appliances

The officially supported hypervisors for the virtual appliances have been changed with GOS 21.04. The GSM EXA/PETA/TERA/DECA and 25V can be used with Microsoft Hyper-V, VMware vSphere Hypervisor (ESXi), and Huawei FusionCompute; the GSM CENO can be used with Microsoft Hyper-V and VMware vSphere Hypervisor (ESXi); and the GSM ONE can be used with Oracle VirtualBox, VMware Workstation Pro, and VMware Workstation Player. Additionally, GOS 21.04 supports the ARM instruction set on Huawei FusionCompute.

Improvement of the Web Server, Ciphers and Web Certificates

With GOS 21.04, the nginx web server is used in addition to the Greenbone Security Assistant Daemon (gsad). This web server uses OpenSSL instead of GnuTLS to define the available ciphers and protocols of the server. There is now a new menu in the GOS administration menu for configuring the TLS version. In addition, the menu for configuring the ciphers has been adapted.

Another change can be found in the generation of HTTPS certificates. Here it is now possible to define one or more Subject Alternative Name(s) (SAN). These are used to cover multiple domain names and IP addresses with one certificate.

CVSS v3.0/v3.1 Support for Severity Calculation

CVSS version 3.0 and 3.1 are now supported for calculating the severity of CVEs (Common Vulnerability Enumeration).

VTs and CVEs can contain version 2 and/or version 3.0/3.1 CVSS data. If a VT/CVE contains both CVSS v2 data and CVSS v3.0/v3.1 data, the CVSS v3.0/v3.1 data is always used and displayed.

The page CVSS Calculator now contains both a calculator for CVSS v2 and a calculator for CVSS v3.0/v3.1.

Open Scanner Protocol Makes all Sensor GSMs Lightweighted

Already with GOS 20.08 it was optionally possible for all sensors to be controlled via the Open Scanner Protocol (OSP). This results in the sensors becoming lightweighted and avoids the need for additional credentials on the sensor.

With GOS 21.04, only OSP is now used as the protocol to control a sensor GSM via a master GSM. The Greenbone Management Protocol (GMP) is no longer used.

Simplified and More Intuitive Functions on the Web Interface

With GOS 21.04, some minor changes have also been made to GOS and the web interface to make GSM operation and scanning clearer and more intuitive.

For example, the Auto-FP function and the alternative severity class schemes – BSI Vulnerability Traffic Light and PCI-DSS – have been removed.

Some devices – especially IoT devices – can crash when scanned across multiple IP addresses simultaneously. This can happen, for example, if the device is connected over IPv4 and IPv6. With GOS 21.04, it is possible to avoid scanning over multiple IP addresses at the same time by using the new setting Allow simultaneous scanning via multiple IPs when creating a target.

See for Yourself!

Check out our new features and changes for yourself! New appliances with GOS 21.04 are now available and existing appliances can also be upgraded to the latest version. Also our free trial version can be used with GOS 21.04.

We are pleased to inform you that the latest version of our operating system Greenbone OS is now available! We have taken many of your wishes into account: the focus of the improvement was the scanning of large networks with many scan results and extensive reports. Among other things, GOS 21.04 offers new hardware, an improvement of host detection and clearer reports.

Delivering the best vulnerability management to our customers – this goal has always been at the core of our products. With the new release of our operating system Greenbone OS, we stay true to this claim and make our products more powerful: especially for large networks with many distributed branch offices, scanning with GOS 21.04 is faster and the scan results are even clearer.

More powerful and faster hardware for the Midrange Class

In large networks, several distributed medium-sized to large appliances are usually used, linked together via a master-sensor setup. For this reason, the Midrange Class hardware appliances have been strengthened by improving their hardware.

Our new hardware now uses SSD-type hard disks instead of HDD, which are 10 times faster, quieter and lighter. There is also more storage space available. The RAM has also been improved: instead of DDR3, it is now DDR4, which is much faster due to a higher clock rate (3200 MHz). Furthermore, twice to four times as much working memory is available than before. In addition, the hardware received new, faster CPU of the latest generation and also the ports of the appliances were updated: instead of 6 ports GbE-Base-TX and 2 ports 1 GbE SFP there are now 8 ports GbE-Base-TX and 2 ports 10 GbE SFP+.

Boreas Alive Scanner for faster availability of results now as standard

Scanning is also getting faster – which is especially helpful in large networks. GOS 20.08 already introduced the Boreas Alive Scanner, a host alive scanner that identifies the active hosts in a target network. With GOS 21.04, the Boreas Alive Scanner becomes standard, eliminating the need for manual activation.

The Boreas Alive Scanner is not limited in terms of the maximum number of simultaneous alive scans it can perform, making it faster than its predecessor Nmap. This significantly reduces the scanning time for large networks. Initial scan results are available faster, regardless of the percentage of reachable hosts in the network.

Clearer reports thanks to new report formats

The evaluation of scans is also clearer – thanks to new report formats. With the Vulnerability Report format as PDF and as HTML, the reports are clearly structured and easy to read. Specific information relevant to the target group can be quickly identified and understood.

See for Yourself

Scanning with GOS 21.04 is even faster, more reliable and clearer. Convince yourself of our new features and changes! New appliances with GOS 21.04 are available now. For existing appliances, the upgrade to the latest version will be available next week. Also our free trial version will be usable with GOS 21.04 then.

The water sector is one of the critical infrastructures (CRITIS). A successful attack on the sector can lead to significant hygiene and health problems and, in the worst case, threaten human lives. At the 6th VDI conference on “Optimizing Industrial Wastewater Treatment Plants”, Greenbone will provide information on vulnerability management in the water sector and how the attack surface of IT infrastructures can be reduced by early detection and elimination of vulnerabilities.

Everything Fine Thanks to Digitization? Digitization is seen as the savior of the hour. Even if this may be viewed critically at times, this development cannot be stopped. There are simply too many reasons in favor of digitization. But there are also many reasons that we need to take a critical look at, especially where our security is concerned. The more information technology we put in place, the more digitized attack surfaces we offer. Malicious users of these attack surfaces can operate globally, and likewise digitized currencies like Bitcoin allow them to profit from vulnerabilities globally as well. Unlike a bank robbery, an attack on an industrial wastewater facility is more of a a means to an end. The attacker does not want the contents of a safe, but rather targets the vulnerability as such in order to gain advantages, usually through blackmail. Not only technical systems themselves are attacked, but often also the technical and organizational environment from networks to administration. These attackers are not hackers with hoodies and matrix screen savers who just happen to have emergency on their account, but criminal organizations that are industrially and professionally organized. We must arm ourselves against them with resilient organizations, processes and solutions. This brings the topic of cyber resilience more and more to our attention. Cyber resilience is the ability of a company or organization to maintain its business processes despite adverse cyber circumstances. These can be cyber attacks, but also unintentional obstacles such as a failed software update or human error. Cyber resilience is a comprehensive concept that goes beyond IT security. It combines the areas of information security, business continuity, and organizational resilience. To achieve a state of cyber resilience, it is important to identify vulnerabilities early, prioritize them economically, and eliminate them. Why Cyber Resilience Is Particularly Important for Critical Infrastructures Sustainable cyber resilience is important for companies in all industries. But it is indispensable in the area of critical infrastructure (CRITIS). As defined by the German government, this includes “organizations or facilities of critical importance to the state community, the failure or impairment of which would result in sustained supply shortages, significant disruptions to public safety, or other dramatic consequences.” CRITIS organizations must therefore protect themselves particularly well against cyber attacks – this is required by law. The EU launched the European Programme for Critical Infrastructure Protection (EPCIP) back in 2006 and expanded and supplemented it in subsequent years. Member states are implementing the EU NIS directive in national law, Germany for instance with the IT Security Act (IT-SIG). Large economic nations have already developed regulatory bodies. In the U.S., for example, this is the National Institute of Standards and Technology (NIST) and in Germany the Federal Office for Information Security (BSI). In Germany, the critical infrastructures are divided into 9 sectors. One of these is the water sector with the divisions of public water supply and wastewater disposal. It includes, for example, waterworks, pumping stations, water pipelines and networks, wastewater treatment plants, the sewerage system, and dam and flood protection facilities. They all play a critical role in our society. Attacks on the water supply could therefore hit a society to the core and, in the worst case, threaten human lives. Attacks on the wastewater disposal system are just as dangerous. If it no longer functions, the result would be considerable hygienic and health problems. Since the water infrastructure uses many IT systems and electronic control systems (ICS) nowadays, it becomes an attractive target for hackers. Incidents Show the Vulnerability of the Water Sector In recent years, there have been numerous attacks on water infrastructures worldwide. Fortunately, there have been no serious consequences so far. However, the attacks show that hackers are exploring how to take control of control systems and prepare further attacks. In 2013, for example, Iranian hackers attempted to penetrate the systems of the Bowman Avenue Dam near the town of Rye Brooke, near New York. The dam is used to control the flow of water after heavy rains and prevent flooding of the town. The hackers managed to gain control over the flood gates’ control system. However, as these were currently offline due to maintenance, the cyber criminals were fortunately unable to cause any damage. In March 2016, security specialist Verizon reported a cyber attack on a U.S. water utility known by the pseudonym Kemuri Water Company in its monthly Security Breach Report. Hackers had penetrated the SCADA platform. This allowed them to manipulate programmable logic controllers. They changed settings on the water flow and the amount of chemicals added for water treatment. Fortunately, the water utility quickly discovered the incident and was able to correct the settings without causing any major damage. For their attack, the hackers exploited an unpatched vulnerability in the customer payment portal. Between November 2016 and January 2017, cyber criminals hacked several wireless routers at a U.S. water agency. The routers were used to provide secure wireless access for pump station monitoring. Fortunately, however, the attackers were not looking to sabotage, but were targeting the agency’s Internet resources. Their bill rose from an average of $ 300 per month to a whopping $ 45,000 in December and $ 53,000 in January. For their attack, the hackers exploited a vulnerability in the routers of the manufacturer Sixnet. According to its own information, Sixnet had already made a patch available in May, but the authority had not installed it. Over the past year, Israel has been the victim of multiple cyber attacks on water supply and treatment facilities. In April, hackers undertook a major cyber attack on control and monitoring systems at wastewater treatment plants, pumping stations and sewers, the Israeli National Cyber Directorate (INCD) said in a statement. The INCD then demanded companies in the water sector to change passwords for all systems connected to the Internet-connected systems and to ensure that control system software is up-to-date. The hackers attempted to change the chlorine content of water at a water treatment plant. The attack was not successful. Had it been, it could have resulted in mild intoxication of the population served by the treatment plant. Back in June, there were two more attacks on Israel’s water facilities. This time, agricultural water pumps were affected. Although there has not yet been a comparable incident in Germany, the Federal Office for Information Security (BSI) reports about the implementation of the necessary organizational and technical precautions to prevent disruptions in its current report on the state of IT security in Germany. In the water sector, this reveals deficiencies in the areas of network separation, emergency management and physical security. In the reporting period from June 2019 to May 2020, there were several incidents in the water sector in Germany that were due to faults in control components. Remediation of the malfunctions was very lengthy and costly. Damage was avoided by operators acting prudently and having redundancies in place. Attack Points in the Water Sector IT and OT systems support the water cycle. In water production (1), quality control systems and digital pump control are used to manage water inflow from various sources towards water distribution (2). Digital metering and control methods monitor water pressure and quality in the water network and are thus part of the overall IT attack surface. In sewage systems (3), wastewater pumps and pre-treatments by filters, which are monitored at central points, are used. Water treatment (4) is a critical component due to the necessary digitalized control of physical, chemical and biological processes. Many networked IT systems and industrial control systems are therefore used in drinking water supply and wastewater disposal, enabling largely automated processes. Examples include sensors for temperature, flow rate, or chlorine content, remotely readable meters, and web portals and mobile apps for customers. Challenges for Cyber Resilience in the Water Sector To reduce their attack surface for cyber criminals, water sector organizations must consider the full range of networked systems, devices and applications. But this is not always easy. One problem is that the ICSs used in the water infrastructure come from different generations. Many of the older control systems were developed at a time when little or no consideration was given to cyber security. This leads to a heterogeneous, vulnerable IT landscape. Additionally, the high degree of automation and dependence on industrial controls makes water infrastructure particularly vulnerable to attack. Furthermore, the IT systems in use are becoming increasingly complex. This makes it difficult for companies to achieve a sufficient level of protection. The increasing networking of components within the field and control level as well as the control and process control technology increases the complexity even further.  At the same time, this increases the attack surface for hackers. They have more and more opportunities to penetrate networks, steal data or manipulate industrial controls. Even Previously Unexploited Vulnerabilities Should Not Be Underestimated A recent study by Kenna Security found that the total number of vulnerabilities discovered per year has increased from 4,100 in 2011 to 17,500 in 2021. On the other hand, the percentage of vulnerabilities exploited by hackers has not grown at the same rate. What is the reason for this? Cyber crime follows the same economic rules as any other business model: least investment for maximum result. But cyber crime also suffers from the same problem as the IT industry in general: experts are a limited resource. Companies cannot change this initial situation, but they can ensure that their attack surface is reduced. Tolerating a large attack surface, even if the vulnerabilities are not yet weaponized, is replacing control with gambling. As soon as it seems cheaper for cyber criminals or the outcome is promising, cyber crime will focus on vulnerabilities that are not yet weaponized, and the conversion of vulnerabilities into weapons will happen quickly. Even worse is the motivation of cyber terrorists, who have so far been fortunately unsuccessful due to a lack of expertise. It is unclear whether they will gain the necessary skills and if so, when. But they do not follow the rules of economics, which makes them less predictable in selecting targets and suitable weaponized vulnerabilities. In essence, there are two good general reasons why organizations should establish a process to manage and minimize their entire attack surface and not just focus on current (or likely) weaponizable vulnerabilities:

• Pandemic risk: while it may not be attractive for a single criminal organization to invest in turning a more expensive vulnerability into a weapon, the more organizations choose not to do anything about that vulnerability, the more interesting it becomes. The fewer that are vaccinated, the better the pandemic spreads.
• Automation risk: automating exploits is not only an attractive, cost-effective way to go. It significantly reduces the window of opportunity to respond with countermeasures.

Reduced Attack Surface with Vulnerability Management Regardless of how many vulnerabilities exist, managing damage and actively countering ongoing attacks becomes exponentially expensive for organizations if not accompanied by an ongoing process that identifies, manages and reduces the attack surface. Cyber resilience is a continuous process. It strengthens an organization’s ability to withstand an attack and enables it to continue to function during an attack. To achieve this, it is important to reduce the attack surface and thus stabilize the base. This means identifying vulnerabilities that could be exploited by an attacker and thus staying one step ahead of the attacker. 999 out of 1,000 vulnerabilities have been known for over a year. With vulnerability management, this means that these vulnerabilities can be identified and eliminated before they are exploited by an attacker. This greatly reduces the attack surface of the IT infrastructure. Vulnerability management systems are fully automated and, thanks to features such as schedules and custom scan configurations, offer users the ability to create complete vulnerability management processes that constantly scan for vulnerabilities. As a result, vulnerability management ensures more resilient systems in the long term.

Are there actually independent reviews of Greenbone solutions?
Of course – we are proud to present the latest report from a leading industry magazine: “IT-Administrator tried the system [solution from Greenbone] and was thrilled with its functionality”. (IT Administrator 01/2021)

In September 2020, the magazine IT-Administrator – a German professional journal for system and network administration – asked Greenbone if they could write a test report about a Greenbone appliance.

The report is currently published in the January issue of the magazine. Here you can read the detailed report.

In the test, IT-Administrator took a closer look at the GSM 150. The GSM 150 is a physical appliance designed for vulnerability management in small to medium-sized businesses, or organizations with medium-sized branch offices. It scans up to 500 IP addresses within 24 hours and can also be used as a sensor for larger appliances.

Everything that must be done in a standard deployment of a Greenbone Security Manager was tested: from the initial setup via the console, to configuring scans on the web interface, to evaluating a scan report.

For testing the vulnerability scans, IT-Administrator had prepared different target systems with different security status to examine the differences in the results. Authenticated scans were also part of the test.

Read the full article here (German only).