cbcvebase.
CVE-2022-21999
published 2022-02-09

CVE-2022-21999: Windows Print Spooler Elevation of Privilege Vulnerability

PriorityP187high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
KEVITWEXPLOITRansomware
CISA Known Exploited Vulnerabilitydue 2022-04-15
Exploited in the wild
EPSS
41.68%
98.5th percentile
Windows Print Spooler Elevation of Privilege Vulnerability

Affected

51 ranges· showing 25
VendorProductVersion rangeFixed in
microsoftwindows_10_1507< 10.0.10240.1920410.0.10240.19204
microsoftwindows_10_1607< 10.0.14393.494610.0.14393.4946
microsoftwindows_10_1809< 10.0.17763.256510.0.17763.2565
microsoftwindows_10_1909< 10.0.18363.209410.0.18363.2094
microsoftwindows_10_20h2< 10.0.19042.152610.0.19042.1526
microsoftwindows_10_21h1< 10.0.19043.152610.0.19043.1526
microsoftwindows_10_21h2< 10.0.19044.152610.0.19044.1526
microsoftwindows_10_version_1507>= 10.0.10240.0 < 10.0.10240.1920410.0.10240.19204
microsoftwindows_10_version_1607>= 10.0.14393.0 < 10.0.14393.494610.0.14393.4946
microsoftwindows_10_version_1809>= 10.0.0 < 10.0.17763.256510.0.17763.2565
microsoftwindows_10_version_1809>= 10.0.17763.0 < 10.0.17763.256510.0.17763.2565
microsoftwindows_10_version_1909>= 10.0.0 < 10.0.18363.209410.0.18363.2094
microsoftwindows_10_version_20h2>= 10.0.0 < 10.0.19042.152610.0.19042.1526
microsoftwindows_10_version_21h1>= 10.0.0 < 10.0.19043.152610.0.19043.1526
microsoftwindows_10_version_21h2>= 10.0.19043.0 < 10.0.19044.152610.0.19044.1526
microsoftwindows_11_21h2< 10.0.22000.49310.0.22000.493
microsoftwindows_11_version_21h2>= 10.0.0 < 10.0.22000.49310.0.22000.493
microsoftwindows_7>= 6.1.0 < 6.1.7601.258606.1.7601.25860
microsoftwindows_7_service_pack_1>= 6.1.0 < 6.1.7601.258606.1.7601.25860
microsoftwindows_8.1>= 6.3.0 < 6.3.9600.202696.3.9600.20269
microsoftwindows_server_2008
microsoftwindows_server_2008_r2_service_pack_1>= 6.1.7601.0 < 6.1.7601.258606.1.7601.25860
microsoftwindows_server_2008_service_pack_2>= 6.0.6003.0 < 6.0.6003.213746.0.6003.21374
microsoftwindows_server_2012
microsoftwindows_server_2012>= 6.2.9200.0 < 6.2.9200.236056.2.9200.23605

Detection & IOCsextracted from sources · hover to see the quote

ip27.124.26.83
ip27.124.26.86
filenameArtifactd.exe
filenameclient.exe
filenameew.exe
filenamej.exe
filenameev.exe
pathc:\windows\system32\wmipd.dll
pathC:\Windows\System32\spool\drivers\x64\4
urlHTTPS://+:443/topics/
registryCopyFiles\
  • Detect SpoolFool exploitation by monitoring for creation of the payload drop path C:\Windows\System32\spool\drivers\x64\4 combined with SetPrinterDataEx() calls using the CopyFiles\ registry key, which triggers DLL load as SYSTEM.
  • Monitor for creation of a Windows service named 'WMI Provider' loading wmipd.dll from c:\windows\system32\wmipd.dll as an indicator of OwlProxy deployment.
  • Detect OwlProxy C2 activity by alerting on inbound HTTPS requests to URL prefixes matching /topics/ and /topics/pp/ on port 443, particularly those containing query parameters s?pa= (command execution) or s?pp= (proxy setup).
  • Alert on SpoolFool post-exploitation activity: creation of a local administrator account with username 'admin' and password 'Passw0rd!' via the Windows Print Spooler exploit.
  • Detect SpoolDirectory abuse: monitor for SetPrinterDataEx() calls that set SpoolDirectory to a UNC path or directory junction, which is the prerequisite step for CVE-2022-21999 exploitation.
  • ·The SpoolDirectory path (C:\Windows\System32\spool\drivers\x64\4) is only created if it does not already exist; the exploit relies on the print spooler reinitializing to trigger directory and DLL creation, so detection must account for the reinitialization step.
  • ·OwlProxy's wmipd.dll variant observed in CL-STA-0046 differs slightly from the April 2020 Taiwan samples; hash-based detection of earlier OwlProxy samples may not match this newer variant.
  • ·EarthWorm (ew.exe) is a publicly available SOCKS tunneler not inherently malicious; detections based solely on the binary name or tool behavior may produce false positives in legitimate research or admin contexts.
  • ·The AspxSpy web shell used is publicly available and not exclusive to Gelsemium; detections on this web shell alone should not be used for attribution.

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.04.6MEDIUMAV:L/AC:L/Au:N/C:P/I:P/A:P
vulncheck7.8HIGH
cisa7.8HIGH
vendor_msrc7.8HIGH
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