Vulnerabilities > CVE-2020-8017 - Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in Opensuse Leap and Texlive-Filesystem
Summary
A Race Condition Enabling Link Following vulnerability in the cron job shipped with 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 in group mktex to delete arbitrary files on the system 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.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 3 | |
| OS | 4 | |
| OS | 1 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Leveraging Race Conditions via Symbolic Links This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to her. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file she will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.
- Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. The typical example is the file access. The attacker can leverage a file access race condition by "running the race", meaning that he would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the attacker could do something such as replace the file and cause an escalation of privilege.