PrintNightmare Windows Patch Reportedly Breaks Network Printing Altogether

Windows Update Screen
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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.

While Microsoft's Tuesday Security patch seems to have stomped out the bug entirely, the update process didn't exactly go smoothly. According to the BleepingComputer report, various users of Microsoft's Network Printing functionality have reported that the latest patch is also breaking network printing entirely.

What makes the problem worse is that Windows is reporting different types of errors to each user, making it a bit harder to see what's going on. BleepingComputer said that one source is seeing a 4098 Warning in the application event logs, while another said that their printer port tabs were all blank. One source couldn't even get access to their network printers at all, seeing "access denied" errors instead.

It is important to note that this issue does not appear on printers attached using a USB connector cable. However, network printers from HP, Canon and Konica Minolta have all been reported to be having issues, with other network printers presumably being affected as well. Further, label printers are also affected.

We are sure that Microsoft is aware of the issue and that the company is working hard to iron out these new, less security-focused bugs. PrintNightmare has been a summer long ordeal so far, and unfortunately, it seems like we haven't quite left it behind yet. 

  • Exploding PSU
    as if printing isn't a nightmare already
  • thisisaname
    exploding_psu said:
    as if printing isn't a nightmare already

    Yes but think of how much paper it is going to save ;)
  • chalabam
    This type of problem is guaranteed to happen with windows network printing even before the patch.

    And HP printers are the helliest of all. It is totally normal that you have 2 identical PCs, identically configured, and one sees the printer meanwhile the other can't detect it.

    One day the printer works, and the next day they are gone magically. No change at all on the PC, and the printer vanishes into oblivion.