Microsoft this week released a patch to fix the last vestiges of a remote code execution vulnerability called PrintNightmare (CVE-2021-34527), but while the vulnerability now seems fixed, BleepingComputer reports that the patch seems to have broken network printing altogether.
The PrintNightmare bug is a vulnerability that allows attackers to execute malicious code on users’ systems without having physical access to them. This is, of course, one of the worst possible exploits users can face. Microsoft’s been fighting this security issue since July, but prior to this week’s patch, a hole for hackers still existed within remote printing server access.
The bug took advantage of the Windows Print Spooler service improperly performing privileged file operations. An attacker who had successfully exploited this vulnerability could run malicious code with SYSTEM-level (admin-level) privileges without getting caught in the act.