CVE-2018-1063

Context relabeling of filesystems is vulnerable to symbolic link attack, allowing a local, unprivileged malicious entity to change the SELinux context of an arbitrary file to a context with few restrictions. This only happens when the relabeling process is done, usually when taking SELinux state from disabled to enable (permissive or enforcing). The issue was found in policycoreutils 2.5-11.

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

• https://access.redhat.com/errata/RHSA-2018:0913
• https://bugzilla.redhat.com/show_bug.cgi?id=1550122
• https://access.redhat.com/errata/RHSA-2018:0913
• https://bugzilla.redhat.com/show_bug.cgi?id=1550122