Microsoft Windows Search Remote Code Execution Vulnerability
CVE-2017-8543 is a security vulnerability in Microsoft Windows, added to CISA KEV on May 24, 2022. Patch priority: Patch this week.
What it is
Microsoft Windows allows an attacker to take control of the affected system when Windows Search fails to handle objects in memory.
VulnCheck tracked exploitation 1806 days before CISA's KEV listing. VulnCheck's broader catalog of in-the-wild exploitation evidence picked this up before it landed on CISA's formal list. Per-CVE fact about this entry; not a population claim about lead time in general.
Who's affected
Affects anyone running Windows workstations or servers. In a small CPA, legal, or dental practice, Windows is typically the platform your accounting, document management, or practice management software runs on — exploitation gives an attacker access to whatever client files and credentials live on those machines.
What to do
Apply updates per vendor instructions.
If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.
Insurance readiness
Your insurer will ask if this is patched.
Unpatched entries on CISA's Known Exploited Vulnerabilities list are exactly what cyber-insurance carrier questionnaires probe for, and knowing which controls they check is how you keep a renewal from stalling.
Get the free carrier questionnaire →Severity
CVSS base score: 9.8 — CRITICAL
Weakness classification: CWE-281
Microsoft fix
- KB4022727 (Security Update)
- KB4022714 (Security Update)
- KB4025339 (Security Update)
- KB4025342 (Security Update)
- KB4022719 (Monthly Rollup)
- KB4022722 (Security Only)
- KB4022726 (Monthly Rollup)
- KB4022717 (Security Only)
- KB4024402 (Security Update)
- KB4022724 (Monthly Rollup)
- KB4022718 (Security Only)
Microsoft Exploitability Index (assessed at update release): Exploitation More Likely
This CVE is on CISA's Known Exploited Vulnerabilities catalog. Microsoft's index reflects their release-time forecast, not current observed activity, and is not automatically revised upward when exploitation appears later.
Vendor workaround
Vendor-published workaround
Disable WSearch service
Interactive workaround deployment steps
- Click Start, click Run, type "regedit" (without the quotation marks), and then click OK.
- Expand HKEY_LOCAL_MACHINE
- Expand System, then CurrentControlSet, then Services
- Click on WSearch
- Click the File menu and select Export.
- In the Export Registry File dialog type “WSearch_configuration_backup.reg” and press Save.
- Double-click the value named Start and change the Value data field to 4
- Click OK
- Run the following command at a command prompt running as an administrator:
sc stop WSearch
Impact of workaround The Windows Search functionality will not be available to applications that use it for searches.
How do undo the workaround Click Start , click Run , type "regedit " (without the quotation marks), and then click OK. Click the File menu and select Import. In the Import Registry File dialog select “WSearch_configuration_backup.reg” and press Open.
Managed workaround deployment steps
- First a backup copy of the registry keys can be made from a managed deployment script with the following command: regedit /e WSearch_configuration_backup.reg HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\WSearch
- Next save the following to a file with a .REG extension (e.g. Disable_WSearch.reg)
[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\WSearch]
"Start"=dword:00000004
- Run the registry script created in step 2 on the target machine with the following command: regedit /s Disable_WSearch .reg
- Run the following command at a command prompt running as an administrator: sc stop WSearch
Impact of workaround The Windows Search functionality will not be available to applications that use it for searches.
How to undo the workaround Restore the original state by running the following command: regedit /s WSearch_configuration_backup.reg
A workaround reduces exposure while you patch — it is not a substitute for the update. Install the fix above as soon as you can.
CISA due date
Federal deadline: June 14, 2022. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).
EPSS
EPSS score: 64.1% — higher than 99% of all scored CVEs.
EPSS estimates the probability of exploitation activity in the next 30 days. Every entry on this site is already confirmed exploited, so read it as relative urgency among the things you still have open, not as permission to wait.
Other exploited Microsoft Windows entries
More CISA KEV entries for Microsoft Windows. Same product line, same actively-exploited status.
Source
This entry comes from CISA's Known Exploited Vulnerabilities catalog, public US-Government data we pull daily. The plain-language framing and the what-to-do guidance above are ours. View the original entry on cisa.gov.