CVE-2023-6817 is a high-severity vulnerability affecting the Linux kernel's netfilter: nf_tables component. This vulnerability allows local privilege escalation due to a use-after-free condition that arises when the function nft_pipapo_walk fails to skip inactive elements during its execution. Specifically, this oversight can lead to double deactivations of PIPAPO (Pile Packet Policies) elements, resulting in potential exploitation.
With a CVSS score of 7.8, the impact of this vulnerability is significant. Attackers with local access could exploit this flaw to gain elevated privileges, which could lead to broader system compromise. Organizations should prioritize patching this vulnerability promptly to mitigate potential risks.
The vulnerability was published on December 18, 2023, and is classified under CWE-416, indicating a use-after-free vulnerability. Given its nature and the potential for exploitation, immediate attention to this issue is crucial for maintaining system integrity and security.
Organizations should assess their systems for the presence of affected Linux kernel versions and ensure that they are upgraded past commit 317eb9685095678f2c9f5a8189de698c5354316a to protect against this vulnerability.
Vulnerability Details
The vulnerability described by CVE-2023-6817 is a use-after-free vulnerability found in the Linux kernel's netfilter: nf_tables component. The specific function at fault, nft_pipapo_walk, fails to skip inactive elements during set walks, which can result in double deactivations of PIPAPO elements. This behavior can lead to exploitation and local privilege escalation.
The CVSS score assigned to this vulnerability is 7.8, categorized as high severity. The score reflects a local attack vector, low attack complexity, low privileges required for exploitation, and no user interaction necessary. Furthermore, the vulnerability has a high impact on confidentiality, integrity, and availability.
Affected products include multiple versions of the Linux kernel, particularly versions from 5.6 to 5.15.143 and 5.16 to 6.6.7, along with specific release candidates of version 6.7. The vulnerability was disclosed on December 18, 2023.
Technical Analysis
The root cause of CVE-2023-6817 lies within the nft_pipapo_walk function in the Linux kernel. The function's failure to skip over inactive elements during its operation creates a scenario where PIPAPO elements can be deactivated multiple times. This double deactivation leads to a use-after-free condition, enabling local privilege escalation.
The attack vector for this vulnerability is local, meaning that an attacker must have local access to the system to exploit it. The attack complexity is rated as low, suggesting that the conditions required for exploitation are easily achievable. Only low privileges are necessary for an attacker to exploit this vulnerability, and no user interaction is required.
In terms of impact, the vulnerability poses a high risk to confidentiality, integrity, and availability. Successful exploitation may lead to unauthorized access to sensitive information, modification of critical system components, or disruption of services.
Risk & Impact Analysis
The real-world risk associated with CVE-2023-6817 is substantial. Given the local attack vector and the potential for privilege escalation, an attacker could leverage this vulnerability to gain control over affected systems. This escalation could lead to a breach of sensitive data or unauthorized modification of critical system components.
Organizations utilizing vulnerable Linux kernel versions must recognize the urgency of this threat. The potential blast radius for organizations with extensive deployment of affected systems is considerable, as an attacker could exploit this vulnerability to gain access across multiple systems.
The urgency assessment, based on the CVSS score of 7.8 and the lack of available public exploits, suggests that organizations should address this vulnerability in their priority patch cycle. Proactive measures should be taken to ensure that all impacted systems are updated without delay.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The affected versions of the Linux kernel include all versions from 5.6 to 5.10.204, 5.11 to 5.15.143, 5.16 to 6.1.68, and 6.2 to 6.6.7, including several release candidates of version 6.7. Organizations are advised to upgrade to versions post commit 317eb9685095678f2c9f5a8189de698c5354316a to mitigate this vulnerability.
Mitigation & Remediation
To remediate CVE-2023-6817, organizations should apply the recommended patch immediately. This patch is included in Linux kernel versions beyond commit 317eb9685095678f2c9f5a8189de698c5354316a. For those unable to apply the patch, implementing strict access controls and monitoring system logs for unusual activity are advisable workarounds.
Organizations should also consider hardening their Linux kernel configurations and ensuring that security updates are applied regularly. Network controls such as firewalls can further reduce the risk of exploitation.
Regular penetration testing should be conducted to identify similar weaknesses within the system.
Detection Guidance
To detect potential exploitation of CVE-2023-6817, organizations should monitor system logs for indicators of abnormal behavior, such as unauthorized privilege escalations. Behavioral anomalies that deviate from typical user activities may also indicate attempts to exploit this vulnerability.
Network signatures that correlate with local privilege escalation attempts should be established and monitored. Additionally, any changes to system configurations or kernel modules should be documented and reviewed regularly.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2023-6817 highlights the persistent vulnerabilities that exist within widely used technologies such as the Linux kernel. This vulnerability serves as a reminder for security teams to continually assess their systems for weaknesses and to prioritize timely updates.
The pattern of use-after-free vulnerabilities emphasizes the importance of robust coding practices and thorough testing during the software development lifecycle. By learning from such incidents, organizations can enhance their security posture and mitigate future risks.
Security teams are encouraged to maintain a comprehensive vulnerability management program and conduct regular assessments and security testing to identify and address similar vulnerabilities in the future.
Additionally, organizations should stay informed about the latest threat trends and ensure they have adequate incident response plans in place to react promptly to any potential exploitation attempts.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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