cbcvebase.
CVE-2017-11771
published 2017-10-13

CVE-2017-11771: The Microsoft Windows Search component on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT…

PriorityP270critical9.8CVSS 3.0
AVNACLPRNUINSUCHIHAH
EPSS
64.13%
99.1th percentile
The Microsoft Windows Search component on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows a remote code execution vulnerability when it fails to properly handle DNS responses, aka "Windows Search Remote Code Execution Vulnerability".

Affected

18 ranges
VendorProductVersion rangeFixed in
microsoftwindows_10
microsoftwindows_10
microsoftwindows_10
microsoftwindows_server_2008
microsoftwindows_server_2012
microsoft_corporationwindows_search
msrcwindows_10
msrcwindows_10_version_1511
msrcwindows_10_version_1607
msrcwindows_10_version_1703
msrcwindows_7
msrcwindows_8.1
msrcwindows_rt_8.1
msrcwindows_server_2008
msrcwindows_server_2008_r2
msrcwindows_server_2012
msrcwindows_server_2012_r2
msrcwindows_server_2016

Detection & IOCsextracted from sources · hover to see the quote

  • Attack vector is SMB — monitor for unauthenticated remote SMB connections targeting the Windows Search service (WSearch), particularly from external/untrusted hosts in enterprise environments
  • Exploit involves specially crafted messages sent to the Windows Search service; monitor for anomalous traffic or process activity originating from the WSearch service (searchindexer.exe / searchprotocolhost.exe)
  • This is the fourth Windows Search vulnerability in 2017 Patch Tuesdays — treat WSearch as a high-value attack surface; alert on unexpected child processes or network connections spawned by the Windows Search service
  • Exploitation is rated 'More Likely' for both latest and older software releases by Microsoft; prioritize detection on unpatched Windows Search endpoints
  • ·Workaround disables WSearch entirely via registry key change (Start=4) and service stop; verify WSearch service start type in registry as a detection signal — value of 4 indicates the service has been intentionally disabled (could also be used by an attacker to cover tracks post-exploitation)
  • ·CVE-2017-11771 is NOT related to EternalBlue/WannaCry/Petya SMB vulnerabilities — do not conflate SMB-based detection rules for those campaigns with this vulnerability

CVSS provenance

nvdv3.09.8CRITICALCVSS:3.0/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
vendor_msrc8.1HIGH
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