CVE-2023-30571 is a vulnerability in Libarchive, a library for reading and writing archive formats. The vulnerability allows directories to have world-writable permissions due to a race condition caused by the umask() call inside the archive_write_disk_posix.c file. This race condition can lead to a permanent umask 0 setting, resulting in implicit directory creation with permissions of 0777. Consequently, any low-privileged local user can delete and rename files within these directories. Given that the CVSS score is 3.9, classified as low severity, it poses a moderate risk, particularly in environments where sensitive data may be handled.
Organizations using versions of Libarchive up to 3.6.2 should prioritize addressing this vulnerability, as it could lead to unauthorized access and modification of files by local users. Even though the exploitability of this vulnerability is rated low, it is advisable to assess the impact within a specific environment, as the implications can vary based on the local user access levels.
As of now, there are no known public exploits for this vulnerability, and it is not included in the Known Exploited Vulnerabilities (KEV) catalog, indicating that it has not been actively exploited in the wild. Nonetheless, organizations should remain vigilant and consider remediation steps as part of their ongoing security posture.
Organizations should assess their dependency on Libarchive and determine if they are using affected versions. If so, they should implement patches immediately to mitigate the risks associated with this vulnerability.
Vulnerability Details
Libarchive through 3.6.2 can cause directories to have world-writable permissions. The umask() call inside archive_write_disk_posix.c changes the umask of the whole process for a very short period of time; a race condition with another thread can lead to a permanent umask 0 setting. Such a race condition could lead to implicit directory creation with permissions 0777 (without the sticky bit), which means that any low-privileged local user can delete and rename files inside those directories.
The CVSS score assigned is 3.9, which indicates a low severity level. This is characterized by the following metrics: attack vector is local, with high attack complexity and low privileges required. User interaction is required, and the potential impact on confidentiality and integrity is low, with no impact on availability.
Technical Analysis
The root cause of this vulnerability lies in the improper handling of the umask setting within a multi-threaded context. When the umask() function is called, it temporarily affects the entire process, which can be exploited by another thread to set the umask to 0, leading to insecure directory permissions.
The attack vector is local, which means that the vulnerability can only be exploited by local users with access to the system. The attack complexity is rated high, requiring specific conditions to be met for the attack to succeed. Privileges required for exploitation are low, meaning an attacker needs only standard user privileges. User interaction is required, which adds another layer of complexity.
The potential impacts of this vulnerability include low confidentiality and integrity impacts, while availability remains unaffected. The overall risk is mitigated by the requirement for local access and specific timing in the exploitation process.
Risk & Impact Analysis
Risk to organizations includes unauthorized access to sensitive files by local users. The potential for a low-privilege user to delete or rename important files could lead to operational disruptions or data integrity issues. Depending on the environment and the value of the data stored, the implications can range from minimal to severe.
Organizations should assess their exposure to this vulnerability, particularly in environments where multiple low-privilege users have access. Although the severity is rated low, the impact could escalate based on the context of use.
Given the CVSS score of 3.9 and the absence of known exploits, organizations should schedule remediation but may not need to address it as an immediate priority. However, it remains crucial to evaluate all potential risks associated with this vulnerability.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions of Libarchive prior to 3.6.3 are affected by this vulnerability. Organizations should ensure they have updated their systems to at least version 3.6.3 or later to mitigate this risk.
Mitigation & Remediation
Organizations should prioritize patching their installations of Libarchive by upgrading to version 3.6.3 or later. If immediate patching is not feasible, consider implementing workarounds such as restricting access to directories created by Libarchive or monitoring for unauthorized changes within these directories.
To enhance security, organizations may also implement configuration hardening and network controls that limit access to sensitive directories. Continuous monitoring solutions should be employed to detect any unauthorized file modifications.
Organizations should validate remediation through penetration testing to ensure that all vulnerabilities are addressed effectively.
Detection Guidance
Monitoring for changes in directory permissions and unauthorized file access attempts is essential. Log indicators should include file creation and deletion events, as well as changes to directory attributes.
Behavioral anomalies such as unexpected file access patterns or permission changes should also be investigated promptly. Employing network signatures that detect unusual traffic patterns can help identify potential exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2023-30571 lies in its demonstration of how race conditions in multi-threaded applications can lead to serious security vulnerabilities. This vulnerability serves as a reminder for security teams to conduct thorough code reviews and implement strict testing procedures across all components.
The trend of vulnerabilities related to permission settings highlights the need for robust access controls and regular audits of permission configurations. Organizations should incorporate lessons learned from this vulnerability into their development and security practices.
Building a comprehensive vulnerability management program can help organizations respond proactively to similar vulnerabilities in the future.
Adopting effective penetration testing methodologies will further help in identifying and mitigating risks associated with vulnerabilities like CVE-2023-30571.
Following security testing best practices is crucial for maintaining a secure environment.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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