CVE-2020-12049

An issue was discovered in dbus >= 1.3.0 before 1.12.18. The DBusServer in libdbus, as used in dbus-daemon, leaks file descriptors when a message exceeds the per-message file descriptor limit. A local attacker with access to the D-Bus system bus or another system services private AF_UNIX socket could use this to make the system service reach its file descriptor limit, denying service to subsequent D-Bus clients.

Weakness

The product does not release or incorrectly releases a resource before it is made available for re-use.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/125.html
• https://cwe.mitre.org/data/definitions/130.html
• https://cwe.mitre.org/data/definitions/131.html
• https://cwe.mitre.org/data/definitions/494.html
• https://cwe.mitre.org/data/definitions/495.html
• https://cwe.mitre.org/data/definitions/496.html
• https://cwe.mitre.org/data/definitions/666.html

References

• http://packetstormsecurity.com/files/172840/D-Bus-File-Descriptor-Leak-Denial-Of-Service.html
• http://www.openwall.com/lists/oss-security/2020/06/04/3
• https://gitlab.freedesktop.org/dbus/dbus/-/issues/294
• https://gitlab.freedesktop.org/dbus/dbus/-/tags/dbus-1.10.30
• https://gitlab.freedesktop.org/dbus/dbus/-/tags/dbus-1.12.18
• https://gitlab.freedesktop.org/dbus/dbus/-/tags/dbus-1.13.16
• https://security.gentoo.org/glsa/202007-46
• https://securitylab.github.com/advisories/GHSL-2020-057-DBus-DoS-file-descriptor-leak
• https://usn.ubuntu.com/4398-1/
• https://usn.ubuntu.com/4398-2/