An advisory on Thursday describes the problem as an “incorrect command-line parameter validation” that also allows an attacker to overwrite arbitrary files.
Privilege escalation can be accomplished via the -modulepath argument by setting an insecure path to modules loaded by the X.org server. Arbitrary file overwrite is possible through the -logfile argument, because of improper verification when parsing the option.
OpenBSD, the free and open-source operating system with a strong focus on security, uses xorg. On October 18, the project released version 6.4 of the OS, affected by CVE-2018-14665. This could have been avoided, though.
Theo de Raadt, founder and leader of the OpenBSD project, says that X maintainer knew about the problem since at least October 11. For some reason, the OpenBSD developers received the message one hour before the public announcement this Thursday, a week after their new OS release.
“As yet we don’t have answers about why our X maintainer (on the X security team) and his team provided information to other projects (some who don’t even ship with this new X server) but chose to not give us a heads-up which could have saved all the new 6.4 users a lot of grief,” Raadt says.
Had OpenBSD developers known about the bug before the release, they could have taken steps to mitigate the problem or delay the launch for a week or two.
To remedy the problem, the OpenBSD project provides a source code patch, which requires compiling and rebuilding the X server.
submitted by: Arnfried Walbrecht