SUSE Solution Security Risk Report 2021

SUSE Solution Security is committed to delivering best in class software security to its customers and to the open source community.

The primary objectives are to treat software security as an ongoing and continual process. This implies to

At the same time, any software can also contain errors (both deliberate and accidental) which could affect the system's security, including design flaws, programming errors, and backdoors.

The SUSE Security Team addresses all of these aspects of software security on an ongoing basis. Software security cannot be thought of as a state you can achieve at a specific point in time. Instead, it is a process that must be executed with professional expertise and continuous development. This persistent focus is what has given open source software, Linux and SUSE such an excellent reputation for security.

Software provides security features (such as authentication methods, encryption, intrusion prevention and detection, backup and others). However, it can also contain errors (such as design flaws, programming errors, and even backdoors) that often turn out to be relevant for the system's security. The SUSE Security Team's task is to addresses all of these aspects of software security, with the understanding that security in software is a challenge that never ends. Software security cannot be understood a state taken at some certain point in time; it is a process that must be filled with professional expertise and permanent development, both on software and on skills. The resulting evolution is what has given open source software, Linux and SUSE its excellent reputation for security.

A modern Linux operating system, such as SUSE Linux Enterprise Server for enterprise use or the openSUSE community distribution for home use, features a rich set of security programs and functions that range from access controls, intrusion prevention and detection, flexible and trustworthy authentication mechanisms, encryption for files and network connections, file integrity checking utilities, to network analysis tools and monitoring/logging utilities for your system. To complement this, there are advanced tools that help you to securely configure and administer your system, and to securely download and install update packages. These utilities are standard in SUSE products. The update packages fix security bugs that have been found after your product has been released. The security features of your Linux system are waiting for you to explore them. SUSE encourages our customers to take advantage of them to further improve the level of privacy and security that is built into every system by default.

Programs are usually written by humans, and humans make mistakes. By consequence, all software can contain errors. Some of these errors appear as instabilities (the software or the entire system crashes), while others may not have any apparent, visible effect. However, some software errors may introduce a security risk. A local or a remote attacker may be able to feed specially drafted data to the software which takes advantage of the programming error (in the case of a remotely exploitable bug, the data comes from an attached network device, such as a cable or DSL modem, or a wireless network interface card). The application then either crashes, resulting in a Denial of Service (DoS) attack, or it executes code that originates from the attacker, transferring control over the execution context from what the programmer intended to what the attacker has in mind for the exploitation of the error. Depending on the software's function, the resulting security breach can impose little or high security risks for your data and your system, potentially giving an attacker the opportunity to delete, alter or even steal your data, or use the system for his own purposes.

The SUSE Solution Security team is responsible for handling all SUSE product-related security incidents. In that team, clear and well-defined roles are assigned for tracking new incidents and coordinating needed updates. The team works with all SUSE engineering software specialists.

We use multiple sources to understand security incidents. These sources include the Mitre and NVD Common Vulnerabilities and Exposures (CVE) databases, various security mailing lists (OSS security, Linux distros, distros, bugtraq, and full-disclosure), direct reports, and other Linux vendors databases. We are also part of various pre-notification mailing lists for software components, like Xen, Samba, X.ORG. Confidential pre-notifications about vulnerabilities will be treated according to established responsible disclosure procedures.

We rate the severity of incidents with two different systems, a simplified rating system and the Common Vulnerability Scoring System (CVSS) v3.1 scoring system. The CVSS is an open framework for communicating the characteristics and severity of software vulnerabilities. It is being developed by the US-based non-profit organization FIRST.org: Its main goal is to assign the right score to a vulnerability to help security administrators prioritize responses and resources to specific threats. CVSS v3.1 scoring consists of three metric groups: Base, Temporal, and Environmental. The Base group represents the intrinsic qualities of a vulnerability that are constant over time and across user environments. The Temporal group reflects the characteristics of a vulnerability that change over time. The Environmental group represents the characteristics of a vulnerability that are unique to a user's environment. The Base metrics produce a score ranging from 0 to 10, which can then be modified by scoring the Temporal and Environmental metrics. A CVSS score is also represented as a vector string, a compressed textual representation of the values used to derive the score. Today, SUSE uses the Base score methodology to evaluate vulnerabilities throughout the support lifecycle of our products. SUSE keeps the right to adjust the final score of the vulnerability as more details become known and available throughout the analysis. The most current CVSS resources can be found at https://www.first.org/cvss/ . The CVSS v3.1 calculator used by SUSE could be found at https://www.first.org/cvss/calculator/3.1. The framework is measuring the severity of a given vulnerability, not the associated risk alone. The scoring of any vulnerability may vary with different analysts hence the final score could be slightly different between vendors impacted by that vulnerability. For a more accurate assessment of the impact, vendors and application owners must always consider factors outside of CVSS such as exposure or threat.

The security incidents are tracked in our own workflow system, technical details are tracked in the SUSE bug-tracking system, and the updated software package is built, processed, and published by our internal “Open Build System”. Internal Service Level Agreements (SLAs) corresponding to the severity rating are monitored and reviewed regularly. Our packagers backport the required security fixes to our version of the software. To protect the stability of our customer setups, we only rarely do minor version upgrades. After receiving fixes for the affected software, four eye reviews cross-check the source patches. A number of automated checks verify source and binary compatibility and the completeness of patch meta information. They also check whether patches can be installed without problems. Dedicated QA teams provide integration, bugfix, and regression testing for all updates before they are released to our customers. After the release of an update, automated processes publish the updates, update notices, and cross reference information on our CVE index pages and machine-readable OVAL and CVRF XML information.

The objective of this report is to provide a summary of all security vulnerabilities which affected SUSE products in calendar year 2021. We will go into details on the high impact vulnerabilities which affected our products in 2021 and elaborate on how we responded to these incidents. For a better understanding of our classification mechanisms, we have described our rating system along with the equivalency of each rating to the CVSS v3.1 scoring calculator:

It is a general policy rule that no new upstream versions of a package are introduced into our enterprise products. This rule is not an absolute rule however. For certain types of packages, in particular antivirus software, security concerns weigh heavier than the conservative approach that is preferable from the perspective of quality assurance. For packages in that class, occasionally newer versions are introduced to a released version of an enterprise product line.

Sometimes also for other types of packages the choice is made to introduce a new version rather than a backport. This is done when producing a backport is not economically feasible or when there is a very relevant technical reason to introduce the newer version.

The SUSE Solution Security team observed a steady amount of vulnerabilities hitting our products on an annual basis. More and improved tools are now available for finding out zero-day vulnerabilities and scanning for existing vulnerabilities. Such instruments can validate and report back if the application code written is following the standard security best practices or there are major gaps in potential attack vectors such as buffer overflow, denial of service or unwanted elevated access. It is obvious that developers are becoming more and more security aware and the quality of the code being developed has greatly improved in both quantity and quality. While we notice an increasing number of important vulnerabilities, the number of critical vulnerabilities is going down year over year.

Figure 1: Security updates and patches released per month #

  

Securing our software supply chain is a top priority for SUSE to ensure that our customers are protected from security risks, known and zero-day vulnerabilities. Ensuring that no threat actor can inject malicious code within our build service systems is certified by industry leading security certifications. Our teams continually work to certify all SUSE products, and develop security solutions to ensure the highest level of trust and reliability for our customers.

Common Criteria (CC), also known as the Common Criteria for Information Technology Security Evaluation, is an international set of specifications and guidelines designed by the signatories of the Common Criteria Recognition Arrangement (CCRA), to evaluate information security products and systems. It was developed to ensure that products and systems meet a predefined security standard for government deployments. Products and systems that have been successfully tested and evaluated by a licensed laboratory are awarded a Common Criteria certification. On November 11th 2021, SUSE was awarded with the Common Criteria Certification (NIAP OSPP) for SUSE Linux Enterprise Server 15 SP2. This certification is mandatory for work with the United States (US) Federal Government. It demonstrates compliance to NIAP Protection Profile for General Purpose Operating Systems, Version 4.2.1 (CCEVS-VR-PP-0047) with the Extended Package for Secure Shell (SSH), Version 1.0 (CCES-VR-PP-0039). This certification extends our Common Criteria Certification track by US Compliance Regulations enabling US federal entities to profit from SUSE’s Certified Secure Software Supply Chain while complying with all necessary national regulations.

The National Institute of Standards and Technology (NIST) developed the FIPS 140-2 security standard. It outlines the security requirements that must be satisfied by cryptographic modules, providing four increasing, qualitative levels intended to cover a wide range of potential applications and environments. On October 27th 2021, NIST awarded SUSE a validation certificate for the Libica Cryptographic Module, a software-hybrid module that provides general purpose cryptographic algorithms to applications running in the user space of the underlying operating system, SUSE Linux Enterprise Server on the IBM Z mainframes. More details about SUSE Linux Enterprise Server on IBM Z can be found at https://www.suse.com/products/systemz/.

Many other industry standards like Defense Counterintelligence Security Agency (DCSA) and the Defense Information Systems Agency (DISA) Security Requirements Guides (SRGs) and Security Technical Implementation Guides (STIG) depend on FIPS 140-2 certified cryptography modules. On July 22nd 2021, the National Institute of Standards and Technology (NIST) under the Cryptographic Module Validation Program (CMVP) in compliance with the Federal Information Processing Standards (FIPS) 140-2, has validated all modules within SUSE Linux Enterprise Server 15 SP2. More details can be found at https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-security-fips.html .

On July 8th, 2021, SUSE announced that SUSE Linux Enterprise Server 15 SP2 is now EAL 4+ level certified for IBM Z, Arm and x86-64. SUSE is the only provider of a recent general-purpose Linux operating system with a secure software supply chain that is certified Common Criteria EAL 4+ for all these platforms. SUSE Linux Enterprise Server 15 SP2 was certified by BSI, Germany's Federal Office for Information Security, based on an evaluation conducted by atsec information security. To achieve the certifications, the SUSE products, and processes for developing and maintaining its products, passed a rigorous security evaluation performed by Atsec Information Security. The certificates were issued by Bundesamt für Sicherheit in der Informationstechnik (BSI) the German Federal Office for IT Security. The Common Criteria for Information Technology Security Evaluation is an international standard (ISO/IEC 15408), recognized by 26 countries (CCRA) worldwide. Details regarding SUSE’s full “Common Criteria Part 3 conformant EAL 4 augmented by ALC_FLR.3 Systematic Flaw Remediation” certification are listed at https://www.bsi.bund.de/SharedDocs/Zertifikate_CC/CC/Betriebssysteme/1151.html?nn=513260 .

On January 29th 2021, the Defense Information Systems Agency (DISA) has released the SUSE Linux Enterprise Server 15 Security Technical Implementation Guide (STIG). Details regarding STIG can be found at https://www.suse.com/c/sles-15-security-technical-implementation-guide-stig/ .

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