cbcvebase.
CVE-2022-21882
published 2022-01-11

CVE-2022-21882: Win32k Elevation of Privilege Vulnerability Win32k Elevation of Privilege Vulnerability

high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2022-02-18
Exploited in the wild
EPSS
55.71%
98.9th percentile
Win32k Elevation of Privilege Vulnerability Win32k Elevation of Privilege Vulnerability

Affected

19 ranges
VendorProductVersion rangeFixed in
microsoftwindows_10_version_1809>= 10.0.0 < 10.0.17763.245210.0.17763.2452
microsoftwindows_10_version_1809>= 10.0.17763.0 < 10.0.17763.245210.0.17763.2452
microsoftwindows_10_version_1909>= 10.0.0 < 10.0.18363.203710.0.18363.2037
microsoftwindows_10_version_20h2>= 10.0.0 < 10.0.19042.146610.0.19042.1466
microsoftwindows_10_version_21h1>= 10.0.0 < 10.0.19043.146610.0.19043.1466
microsoftwindows_10_version_21h2>= 10.0.19043.0 < 10.0.19044.146610.0.19044.1466
microsoftwindows_11_version_21h2>= 10.0.0 < 10.0.22000.43410.0.22000.434
microsoftwindows_server_2019>= 10.0.17763.0 < 10.0.17763.245210.0.17763.2452
microsoftwindows_server_2022>= 10.0.20348.0 < 10.0.20348.46910.0.20348.469
microsoftwindows_server_version_20h2>= 10.0.0 < 10.0.19042.146610.0.19042.1466
msrcwindows_10_version_1809
msrcwindows_10_version_1909
msrcwindows_10_version_20h2
msrcwindows_10_version_21h1
msrcwindows_10_version_21h2
msrcwindows_11_version_21h2
msrcwindows_server_2019
msrcwindows_server_2022
msrcwindows_server_version_20h2

Detection & IOCsextracted from sources · hover to see the quote

processWin32k.sys
filenamestart.ps1
filenamestage.ps1
  • CVE-2022-21882 is a data-only exploit that copies the NT/Authority System privilege token to the current (exploit) process for privilege escalation. Monitor for this specific token-stealing pattern.
  • The vulnerability is triggered via the Win32k.sys user-mode callback function xxxClientAllocWindowClassExtraBytes; monitor for suspicious user-mode callbacks from Win32k.
  • BlueSky ransomware exploiting CVE-2022-21882 runs a Base64-encoded PowerShell script (start.ps1) followed by stage.ps1 for privilege escalation when not running as administrator; detect PowerShell execution of these scripts.
  • Check Point IPS signature 'Microsoft Windows Win32k Elevation of Privilege (CVE-2022-21882)' can be used for network-level detection.
  • ·CVE-2022-21882 is a bypass of the patch for CVE-2021-1732; environments patched for CVE-2021-1732 but not CVE-2022-21882 remain vulnerable, as the earlier patch was insufficient.
  • ·The vulnerability was actively exploited in the wild as of late January 2022, with public PoC exploits disclosed before the February 2022 Patch Tuesday.

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.2HIGHAV:L/AC:L/Au:N/C:C/I:C/A:C
cvelistv57.0HIGH
vulncheck7.0HIGH
cisa7.8HIGH
vendor_msrc7.0HIGH
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