CVE-2017-8806

The Debian pg_ctlcluster, pg_createcluster, and pg_upgradecluster scripts, as distributed in the Debian postgresql-common package before 181+deb9u1 for PostgreSQL (and other packages related to Debian and Ubuntu), handled symbolic links insecurely, which could result in local denial of service by overwriting arbitrary files.

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://metadata.ftp-master.debian.org/changelogs/main/p/postgresql-common/postgresql-common_181+deb9u1_changelog
• http://www.securityfocus.com/bid/101810
• https://usn.ubuntu.com/usn/usn-3476-1/
• https://www.debian.org/security/2017/dsa-4029