Description
The CRC32C feature in the Btrfs implementation in the Linux kernel before 3.8-rc1 allows local users to cause a denial of service (prevention of file creation) by leveraging the ability to write to a directory important to the victim, and creating a file with a crafted name that is associated with a specific CRC32C hash value.
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 | 3.8-1 | — |
| Debian 13 | linux | 3.8-1 | — |
| Debian 12 | linux | 3.8-1 | — |
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 3.3.5 - Btrfs CRC32C feature Infinite Loop Local Denial of Service EDB-38132 · dos · Dec 13, 2012 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- http://www.kernel.org/pub/linux/kernel/v3.x/testing/patch-3.8-rc1.bz2
- http://crypto.junod.info/2012/12/13/hash-dos-and-btrfs/
- https://github.com/torvalds/linux/commit/9c52057c698fb96f8f07e7a4bcf4801a092bda89
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=9c52057c698fb96f8f07e7a4bcf4801a092bda89
- USN-1944-1 vendor-advisory
- USN-1945-1 vendor-advisory
- USN-2017-1 vendor-advisory
- USN-1947-1 vendor-advisory
- [oss-security] 20121213 CVE-2012-5374 CVE-2012-5375 Btrfs CRC32C denial of service issues mailing-list
- USN-1946-1 vendor-advisory