Remote No

Type Privilege escalation

Description

A race condition issue leading to a use-after-free flaw was found in the way the raw packet sockets implementation in the Linux kernel networking subsystem handled synchronization while creating the TPACKET_V3 ring buffer. A local user able to open a raw packet socket (requires the CAP_NET_RAW capability) could use this flaw to elevate their privileges on the system.

AVG-98 linux-zen 4.8.12-1 4.8.12-2 High Fixed

AVG-97 linux-grsec 1:4.8.12.r201612031658-1 1:4.8.12.r201612031658-2 High Fixed

AVG-96 linux-lts 4.4.35-1 4.4.36-1 High Fixed

AVG-95 linux 4.8.12-1 4.8.12-2 High Fixed

07 Dec 2016 ASA-201612-8 AVG-98 linux-zen High privilege escalation

06 Dec 2016 ASA-201612-7 AVG-96 linux-lts High privilege escalation

06 Dec 2016 ASA-201612-6 AVG-95 linux High privilege escalation

06 Dec 2016 ASA-201612-5 AVG-97 linux-grsec High privilege escalation

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=84ac7260236a49c79eede91617700174c2c19b0c
http://seclists.org/oss-sec/2016/q4/607

In order to exploit this issue the attacker needs CAP_NET_RAW capability, which needs to be granted by the administrator to the attacker's account. Without unprivileged user namespaces enabled, local unprivileged users also cannot abuse namespaces to grant this capability to themselves and elevate their privileges.