cbcvebase.
CVE-2022-21907
published 2022-01-11

CVE-2022-21907: HTTP Protocol Stack Remote Code Execution Vulnerability

PriorityP193critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEVInitial access
Exploited in the wild
EPSS
92.79%
99.8th percentile
HTTP Protocol Stack Remote Code Execution Vulnerability

Affected

31 ranges· showing 25
VendorProductVersion rangeFixed in
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
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_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
microsoftwindows_server
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_for_32-bit_systems
msrcwindows_10_version_1809_for_arm64-based_systems
msrcwindows_10_version_1809_for_x64-based_systems
msrcwindows_10_version_20h2_for_32-bit_systems
msrcwindows_10_version_20h2_for_arm64-based_systems
msrcwindows_10_version_21h1_for_32-bit_systems
msrcwindows_10_version_21h1_for_arm64-based_systems
msrcwindows_10_version_21h1_for_x64-based_systems
msrcwindows_10_version_21h2_for_32-bit_systems
msrcwindows_10_version_21h2_for_arm64-based_systems

Detection & IOCsextracted from sources · hover to see the quote

processhttp!UlpAllocateFastTracker()
processhttp!UlFastSendHttpResponse()
versionWindows 2022 Server 10.0.20348.143
versionhttp.sys 10.0.20348.469
  • The vulnerability is triggered in http!UlFastSendHttpResponse() when a specific code path is reached that skips MDL initialization at Tracker offset 0x80, resulting in an invalid call to nt!MmUnmapLockedPages(). Monitor for kernel crashes (BSODs) originating from nt!MmUnmapLockedPages() with an http.sys stack frame as a sign of exploitation attempts.
  • The vulnerable code path requires Tracker->member_0x50 (offset 0x50 in the Tracker structure) to be non-zero and the MDL at Tracker offset 0x80 to be uninitialized. A PoC that crafts HTTP requests to reach this code path can trigger a crash via an invalid MmUnmapLockedPages() call. Kernel debugger breakpoints on nt!MmUnmapLockedPages with invalid BaseAddress arguments can confirm exploitation.
  • IIS is not enabled by default on Windows 10, significantly reducing the attack surface on client systems. Focus detection and patching efforts on Windows Server 2019 and Server 2022 systems running IIS.
  • The patched http.sys version is 10.0.20348.469. Systems running http.sys versions prior to this on Server 2022 are vulnerable. Use file version checks for http.sys as a detection/compliance indicator.
  • ·Windows 10 shares the same vulnerable code path in http.sys, but IIS is not enabled by default, substantially reducing exploitability on client systems.
  • ·Windows clients can also run http.sys independently of IIS, meaning all affected Windows versions (not just servers) should be considered in scope for patching.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.010.0CRITICALAV:N/AC:L/Au:N/C:C/I:C/A:C
vulncheck9.8CRITICAL
vendor_msrc9.8CRITICAL
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