CVE-2020-24332

An issue was discovered in TrouSerS through 0.3.14. If the tcsd daemon is started with root privileges, the creation of the system.data file is prone to symlink attacks. The tss user can be used to create or corrupt existing files, which could possibly lead to a DoS attack.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• http://www.openwall.com/lists/oss-security/2020/08/14/1
• https://bugzilla.suse.com/show_bug.cgi?id=1164472
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SSDL7COIFCZQMUBNAASNMKMX7W5JUHRD/
• https://seclists.org/oss-sec/2020/q2/att-135/tcsd_fixes.patch
• https://sourceforge.net/p/trousers/mailman/message/37015817/
• http://www.openwall.com/lists/oss-security/2020/08/14/1
• https://bugzilla.suse.com/show_bug.cgi?id=1164472
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SSDL7COIFCZQMUBNAASNMKMX7W5JUHRD/
• https://seclists.org/oss-sec/2020/q2/att-135/tcsd_fixes.patch
• https://sourceforge.net/p/trousers/mailman/message/37015817/