CVE-2016-9602

Qemu before version 2.9 is vulnerable to an improper link following when built with the VirtFS. A privileged user inside guest could use this flaw to access host file system beyond the shared folder and potentially escalating their privileges on a host.

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/2017/01/17/12
• http://www.securityfocus.com/bid/95461
• http://www.securitytracker.com/id/1037604
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-9602
• https://lists.debian.org/debian-lts-announce/2018/09/msg00007.html
• https://lists.gnu.org/archive/html/qemu-devel/2017-01/msg06225.html
• https://lists.gnu.org/archive/html/qemu-devel/2017-02/msg04347.html
• https://security.gentoo.org/glsa/201704-01