Proof-of-concept (PoC) code is now available for another Linux kernel vulnerability that could allow attackers to elevate their privileges to root.
Dubbed DirtyDecrypt (aka DirtyCBC), the exploit comes from the V12 security team, which discovered it earlier this month, after fixes were rolled out in April.
The V12 team has not shared a CVE identifier for the security defect, but noted that it is a missing copy-on-write (COW) guard in the rxgk_decrypt_skb component of the RxGK subsystem.
RxGK is a security class for the RxRPC network protocol used by the Andrew File System (AFS) and OpenAFS, which relies on the GSSAPI framework to provide authentication, confidentiality, and integrity protection.
Due to the missing COW guard, oversized response authenticators are accepted, which results in data being written to the memory of privileged processes or to the page cache of privileged files, such as SUID binaries, Moselwal notes.
