cbcvebase.
CVE-2022-26809
published 2022-04-15

CVE-2022-26809: Remote Procedure Call Runtime Remote Code Execution Vulnerability

PriorityP193critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEVRansomware
Exploited in the wild
EPSS
91.32%
99.8th percentile
Remote Procedure Call Runtime Remote Code Execution Vulnerability

Affected

46 ranges· showing 25
VendorProductVersion rangeFixed in
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10_version_1507>= 10.0.10240.0 < 10.0.10240.1926510.0.10240.19265
microsoftwindows_10_version_1607>= 10.0.14393.0 < 10.0.14393.506610.0.14393.5066
microsoftwindows_10_version_1809>= 10.0.0 < 10.0.17763.280310.0.17763.2803
microsoftwindows_10_version_1809>= 10.0.17763.0 < 10.0.17763.280310.0.17763.2803
microsoftwindows_10_version_1909>= 10.0.0 < 10.0.18363.221210.0.18363.2212
microsoftwindows_10_version_20h2>= 10.0.0 < 10.0.19042.164510.0.19042.1645
microsoftwindows_10_version_21h1>= 10.0.0 < 10.0.19043.164510.0.19043.1645
microsoftwindows_10_version_21h2>= 10.0.19043.0 < 10.0.19044.164510.0.19044.1645
microsoftwindows_11_version_21h2>= 10.0.0 < 10.0.22000.61310.0.22000.613
microsoftwindows_7>= 6.1.0 < 6.1.7601.259246.1.7601.25924
microsoftwindows_7_service_pack_1>= 6.1.0 < 6.1.7601.259246.1.7601.25924
microsoftwindows_8.1>= 6.3.0 < 6.3.9600.203376.3.9600.20337
microsoftwindows_server_2008
microsoftwindows_server_2008_r2_service_pack_1>= 6.1.7601.0 < 6.1.7601.259246.1.7601.25924
microsoftwindows_server_2008_service_pack_2>= 6.0.6003.0 < 6.0.6003.214466.0.6003.21446
microsoftwindows_server_2012
microsoftwindows_server_2012>= 6.2.9200.0 < 6.2.9200.236796.2.9200.23679
microsoftwindows_server_2012_r2>= 6.3.9600.0 < 6.3.9600.203376.3.9600.20337
microsoftwindows_server_2016

Detection & IOCsextracted from sources · hover to see the quote

port445
processOSF_SCALL::GetCoalescedBuffer
commandimpacket.dcerpc.v5.rpcrt
  • Monitor for specially crafted RPC calls sent to RPC hosts from unauthenticated remote sources; exploitation results in remote code execution with RPC service permissions.
  • The known PoC exploit targets the vulnerable function OSF_SCALL::GetCoalescedBuffer via a modified RPC pipe type defined in an IDL file; detect anomalous RPC pipe-type usage or unexpected MIDL-compiled interfaces.
  • The PoC uses impacket's dcerpc/rpcrt library to send crafted packets; detect use of impacket RPC tooling (impacket.dcerpc.v5.rpcrt) against Windows RPC endpoints.
  • Block TCP port 445 at the enterprise perimeter firewall as a mitigation; the original researcher used SMB as the attack vector to trigger the exploit in the RPC service.
  • This is a zero-click vulnerability — no user interaction required; alert on inbound unauthenticated RPC connections from external/internet-facing sources, especially to Windows SMB service.
  • ·Blocking TCP 445/139 (SMB) at the perimeter does NOT fully protect against all attack vectors for this vulnerability, since the flaw is in RPC, not SMB. The SMB vector was only the one demonstrated to Microsoft by the submitting researcher.
  • ·The public PoC (published May 1, 2022 on GitHub) only works against a customized RPC server and requires specific server-side settings; it is not a ready-made exploit for default Windows services but could be adapted.
  • ·The threat is not limited to the Windows SMB service; other services using the vulnerable RPC component are also potentially affected.

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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