Exploit of a combination of several bugs - Overhyped but not that severe - Fixes already available
…
Canonical’s security team has acted immediately to quickly apply the patches which Michael Sweet (author and maintainer of CUPS) had already prepared for CUPS, cups-browsed, libcups-filters, libppd, and cups-filters (in the time from the first report until then I was some days off and I was also on the Open Source Summit Europe, thanks, Michael Sweet, for stepping in, also thanks to Zdenek Dohnal from Red Hat) to the appropriate in all supported Ubuntu versions, so that at the time of disclosure most fixes were already in place. They also reported in an Ubuntu blog. They tell users what to do, from turning off cups-browsed or at least its legacy CUPS browsing support to updating their systems as the fixes were already available. Thanks a lot to Seth Arnold, Marc Deslauriers, Diogo Sousa, Mark Esler, Luci Stanescu, and more.
…
The X post really overhyped the vulnerability. Attacks from the internet are not very probable due to the fact that servers on the internet do not have cups-browsed and CUPS installed and CUPS/cups-browsed setups are there usually only in NAT-protected local networks with desktop machines and print servers. And the remote code execution is also rather restricted, as CUPS filters are not running as root, but as the system user “lp” which cannot even read user’s home directories. In addition, the remote code execution only happens when a user actually prints a job on the fake printer. Actually assigned scores ended up between 8.4 and 9.1.
Is that really true? From https://www.evilsocket.net/2024/09/26/Attacking-UNIX-systems-via-CUPS-Part-I/
The very next sentence:
They said they were getting duplicates and non-*nix hits with that 300k number, which doesn’t help them (i.e. the hundreds of thousands of hits was artificially inflated). So yes, the threat is overblown.
Coupled with the fact that patches are already out, and it’s easily mitigated by closing 631, and I don’t expect this will be much of a problem for most people.
My guess is that most hits that scan is gonna catch is old enterprise networks, that has not been updated or maintained by security.