CVE-2019-12779

libqb before 1.0.5 allows local users to overwrite arbitrary files via a symlink attack, because it uses predictable filenames (under /dev/shm and /tmp) without O_EXCL.

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/2019-07/msg00017.html
• http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00027.html
• http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00031.html
• http://www.securityfocus.com/bid/108691
• https://access.redhat.com/errata/RHSA-2019:3610
• https://bugzilla.redhat.com/show_bug.cgi?id=1695948
• https://github.com/ClusterLabs/libqb/issues/338
• https://github.com/ClusterLabs/libqb/releases/tag/v1.0.4
• https://github.com/ClusterLabs/libqb/releases/tag/v1.0.5
• https://security.gentoo.org/glsa/202107-03