Race condition in RunC - CVE-2016-9962
Published: May 17, 2018 / Updated: July 15, 2020
Vulnerability identifier: #VU12804
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/U:Clear
CVE-ID: CVE-2016-9962
CWE-ID: CWE-362
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Docker Inc.
Affected software:
RunC
RunC
Detailed vulnerability description
The vulnerability allows a local attacker to gain elevated privileges on the target system.
The weakness exists due to allowing additional container processes via 'runc exec' to be ptraced by the pid 1 of the container. This allows the main processes of the container, if running as root, to gain access to file-descriptors of these new processes during the initialization and can lead to container escapes or modification of runC state before the process is fully placed inside the container. A local attacker can execute arbitrary code with root privileges.
Successful exploitation of the vulnerability may result in system compromise.
The weakness exists due to allowing additional container processes via 'runc exec' to be ptraced by the pid 1 of the container. This allows the main processes of the container, if running as root, to gain access to file-descriptors of these new processes during the initialization and can lead to container escapes or modification of runC state before the process is fully placed inside the container. A local attacker can execute arbitrary code with root privileges.
Successful exploitation of the vulnerability may result in system compromise.
How to mitigate CVE-2016-9962
Install update from vendor's website.