CVE-2020-8013

A UNIX Symbolic Link (Symlink) Following vulnerability in chkstat of SUSE Linux Enterprise Server 12, SUSE Linux Enterprise Server 15, SUSE Linux Enterprise Server 11 set permissions intended for specific binaries on other binaries because it erroneously followed symlinks. The symlinks cant be controlled by attackers on default systems, so exploitation is difficult. This issue affects: SUSE Linux Enterprise Server 12 permissions versions prior to 2015.09.28.1626-17.27.1. SUSE Linux Enterprise Server 15 permissions versions prior to 20181116-9.23.1. SUSE Linux Enterprise Server 11 permissions versions prior to 2013.1.7-0.6.12.1.

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://lists.opensuse.org/opensuse-security-announce/2020-03/msg00010.html
• https://bugzilla.suse.com/show_bug.cgi?id=1163922