CVE-2021-29646 identifies a medium severity vulnerability present in the Linux kernel versions before 5.11.11. The issue resides in the function tipc_nl_retrieve_key located in net/tipc/node.c, which fails to validate specific data sizes adequately. This vulnerability could potentially lead to a high impact on availability.
With a CVSS score of 5.5, this vulnerability falls under the medium severity classification. Organizations using affected Linux kernel versions are at risk due to potential disruptions in system availability. As this vulnerability is local in nature, it requires a low level of attack complexity and only low privileges for exploitation.
It is crucial for organizations to be aware that the vulnerability has not been added to the Known Exploited Vulnerabilities (KEV) catalog, indicating a lack of known active exploitation in the wild. However, the potential impact on availability necessitates timely remediation.
Organizations should prioritize patching immediately. The recommended action is to update to the latest kernel version (5.11.11 or later) to mitigate the risks associated with this vulnerability.
Vulnerability Details
The vulnerability is characterized by the improper validation of data sizes in the Linux kernel’s TIPC (Transparent Inter-Process Communication) subsystem. The specific function affected is tipc_nl_retrieve_key, which does not enforce sufficient checks on input data, allowing for potential availability disruptions.
The CVSS version 3.1 vector string for this vulnerability is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. This indicates a local attack vector, low attack complexity, and low privileges required for exploitation.
The affected products include various versions of the Linux kernel, specifically all versions prior to 5.11.11. The vulnerability was published on March 30, 2021.
Technical Analysis
The root cause of this vulnerability lies in the inadequate validation of data sizes within the TIPC messaging framework. This oversight can lead to scenarios where an attacker might exploit the vulnerability to cause denial of service or to manipulate system behavior.
The attack vector is local, which means that an attacker must have access to the local system to exploit the vulnerability. Given that the attack complexity is low and only low privileges are required, this vulnerability poses a significant risk to systems that have not been updated.
There is no user interaction required for exploitation, which increases the likelihood of successful attacks on vulnerable systems.
The impacts are defined in terms of availability, which could be compromised. Confidentiality and integrity impacts are noted as none.
Risk & Impact Analysis
Risk to organizations includes potential downtime or service disruption due to this vulnerability. Given the local attack vector and low privileges required, any user with access to the affected system could potentially leverage this vulnerability to affect availability.
The urgency assessment based on the CVSS score indicates that organizations should address this vulnerability in their priority patch cycle. The lack of known exploitation does not diminish the risk it poses, particularly in environments where availability is critical.
The potential blast radius is significant, especially in systems running older kernel versions. Organizations must prioritize patching immediately to prevent possible disruptions.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
This vulnerability affects all versions of the Linux kernel prior to 5.11.11, as well as specific Fedora distributions, including versions 32, 33, and 34.
Mitigation & Remediation
To remediate this vulnerability, organizations should update to the latest version of the Linux kernel (5.11.11 or later). If an upgrade is not immediately feasible, consider implementing configuration hardening and monitoring for any abnormal behavior as a temporary workaround.
Organizations should validate remediation through penetration testing to identify similar weaknesses.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for unusual access patterns, especially around TIPC communications. Behavioral anomalies in kernel operations may indicate attempts to exploit this vulnerability.
Network signatures associated with TIPC could also be valuable in identifying unauthorized access attempts.
AppSecure Threat Intelligence Insight
The significance of CVE-2021-29646 lies in its potential impact on system availability. As organizations increasingly rely on Linux-based systems, understanding vulnerabilities like this is critical for maintaining operational integrity.
This vulnerability underscores the importance of regular updates and the need for effective vulnerability management practices. Security teams should take this incident as a learning opportunity to enhance their defense mechanisms.
For further insights, organizations may explore related topics such as penetration testing methodology, vulnerability management programs, and the cloud penetration testing to enhance overall security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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