Description
kernel/user_namespace.c in the Linux kernel before 3.8.9 does not have appropriate capability requirements for the uid_map and gid_map files, which allows local users to gain privileges by opening a file within an unprivileged process and then modifying the file within a privileged process.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 3.8.11-1 | — |
| Debian 13 | linux | 3.8.11-1 | — |
| Debian 12 | linux | 3.8.11-1 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- Linux Kernel < 3.8.x - open-time Capability 'file_ns_capable()' Local Privilege Escalation EDB-25450 · local · May 14, 2013
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- https://github.com/torvalds/linux/commit/e3211c120a85b792978bcb4be7b2886df18d27f0
- https://github.com/torvalds/linux/commit/6708075f104c3c9b04b23336bb0366ca30c3931b
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=6708075f104c3c9b04b23336bb0366ca30c3931b
- [oss-security] 20130428 Multiple Linux setuid output redirection vulnerabilities mailing-list
- http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.8.9
- 25307 exploit
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=e3211c120a85b792978bcb4be7b2886df18d27f0