CVE-2020-8016 in Linux Enterprise Module for Desktop Applications
Summary
by MITRE
A Race Condition Enabling Link Following vulnerability in the packaging of texlive-filesystem of SUSE Linux Enterprise Module for Desktop Applications 15-SP1, SUSE Linux Enterprise Software Development Kit 12-SP4, SUSE Linux Enterprise Software Development Kit 12-SP5; openSUSE Leap 15.1 allows local users to corrupt files or potentially escalate privileges. This issue affects: SUSE Linux Enterprise Module for Desktop Applications 15-SP1 texlive-filesystem versions prior to 2017.135-9.5.1. SUSE Linux Enterprise Software Development Kit 12-SP4 texlive-filesystem versions prior to 2013.74-16.5.1. SUSE Linux Enterprise Software Development Kit 12-SP5 texlive-filesystem versions prior to 2013.74-16.5.1. openSUSE Leap 15.1 texlive-filesystem versions prior to 2017.135-lp151.8.3.1.
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Analysis
by VulDB Data Team • 05/13/2024
The vulnerability described in CVE-2020-8016 represents a race condition that enables link following within the texlive-filesystem packaging component of multiple SUSE and openSUSE distributions. This race condition occurs during the installation or update process of LaTeX distribution packages, creating a window of opportunity where malicious actors can manipulate symbolic links or file operations to achieve unauthorized system access. The flaw specifically affects desktop application modules and software development kits across different SUSE Linux Enterprise releases, as well as openSUSE Leap 15.1 installations. The technical nature of this vulnerability stems from improper synchronization mechanisms during file system operations, allowing for temporal inconsistencies that can be exploited by local users with minimal privileges.
The core technical flaw manifests as a race condition in the packaging system's handling of symbolic links and file operations within the texlive-filesystem component. When package managers process updates or installations for LaTeX packages, they create temporary symbolic links or modify existing file structures without adequate locking mechanisms. This temporal gap between file creation and finalization allows attackers to manipulate the target files or links during the brief window when the system is processing package operations. The vulnerability is particularly concerning because it can be exploited to corrupt existing files or potentially escalate privileges from standard user accounts to root access levels. This occurs through manipulation of the package installation process where symbolic links are resolved or file operations are executed in an unpredictable order.
The operational impact of this vulnerability extends beyond simple file corruption to potentially enable privilege escalation attacks that could compromise entire system integrity. Local users who have access to the affected systems can exploit this race condition to modify critical system files or install malicious packages that execute with elevated privileges. The attack vector typically involves creating malicious symbolic links in temporary directories or exploiting the timing gap in file creation processes to substitute legitimate files with malicious counterparts. This type of vulnerability aligns with CWE-367, which describes Time-of-Check to Time-of-Use (TOCTOU) flaws, where the state of a resource changes between the time it is checked and when it is used. The potential for privilege escalation makes this particularly dangerous in environments where users might have legitimate access to the system but should not possess administrative privileges.
Mitigation strategies for this vulnerability require immediate patching of affected systems with updated texlive-filesystem packages that address the race condition through proper synchronization mechanisms and locking protocols. System administrators should prioritize updating all affected SUSE Linux Enterprise and openSUSE installations to versions that contain the patched packaging components, specifically targeting the version numbers mentioned in the CVE description. The implementation of proper file system locking during package installation operations and the elimination of temporal gaps in symbolic link resolution should be enforced. Additionally, organizations should consider implementing monitoring solutions to detect suspicious file system operations during package management processes and establish regular security audits to identify any potential exploitation attempts. This vulnerability demonstrates the importance of addressing race conditions in system-level package management components and aligns with ATT&CK technique T1068, which covers 'Local Privilege Escalation' through exploitation of system vulnerabilities.