Microsoft says update now as PrintNightmare security threat return once again

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The security issues in the Windows (opens in new tab) Print Spooler don’t seem to end, as Microsoft has acknowledged yet another remote code execution (RCE) vulnerability in the subsystem.

Tracked as CVE-2021-36958 with a CVSS score of 7.3, the yet-unpatched bug is the latest to join a series of flaws (opens in new tab) collectively known as PrintNightmare (opens in new tab) that have plagued the printer service over the last few months.

Surprisingly though, Microsoft’s acknowledgement of the vulnerability, comes over eight months after it was reported by a cybersecurity researcher in December 2020 (opens in new tab).

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“An attacker who successfully exploited this vulnerability could run arbitrary code with SYSTEM privileges. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights,” says Microsoft (opens in new tab) explaining the newest vulnerability.

Stop press

Will Dormann, a vulnerability analyst for CERT/CC, told BleepingComputer that Microsoft has confirmed that the CVE-2021-36958 vulnerability corresponds to a proof-of-concept shared by security researcher Benjamin Delpy on Twitter (opens in new tab) last month.

Delpy’s trick, explains BleepingComputer, uses the CopyFile registry directive to copy a DLL file, which then opens a command prompt to the client when you connect to a printer.

While Microsoft has since tweaked the permissions of the Point and Print feature (opens in new tab) to require administrative privileges, Delpy PoC will still work since it requires an already-installed driver.

In any case, Microsoft says it is now working to patch the bug. However, in the absence of a fix, Microsoft suggests the only available workaround to mitigate CVE-2021-36958 is to stop and disable the Print Spooler service.

Via BleepingComputer (opens in new tab)

With almost two decades of writing and reporting on Linux, Mayank Sharma would like everyone to think he’s TechRadar Pro’s expert on the topic. Of course, he’s just as interested in other computing topics, particularly cybersecurity, cloud, containers, and coding.