Malicious IIS w3wp Worker Spawning Command Interpreter via SharePoint Web Shell
- Product
- windows
- Category
- process_creation
- Author
- HuntRule
- Published
- 2026-10-04
- Updated
- 2026-10-04
ATT&CK techniques
Initial Access → PersistenceRecon
Resource Dev
Initial Access
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects the IIS worker process w3wp.exe spawning cmd.exe or powershell.exe, behavior consistent with the ToolShell SharePoint exploitation chain executing operator commands through a deployed .aspx web shell. A web server worker launching a shell indicates server-side code execution following exploitation. This is a strong indicator of an active web shell on a SharePoint or IIS host.
Reporting behind it
- intel471.comhttps://www.intel471.com/blog/threat-hunting-case-study-toolshell
- attack.mitre.orghttps://attack.mitre.org/techniques/T1505/003/
- attack.mitre.orghttps://attack.mitre.org/techniques/T1190/
- attack.mitre.orghttps://attack.mitre.org/techniques/T1059/001/
- unit42.paloaltonetworks.comhttps://unit42.paloaltonetworks.com/initial-access-broker-exploits-leaked-machine-keys/
- attack.mitre.orghttps://attack.mitre.org/techniques/T1059/003/
- microsoft.comhttps://www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-premises-sharepoint-vulnerabilities/
- esentire.comhttps://www.esentire.com/blog/threat-actors-use-cve-2019-18935-to-deliver-reverse-shells-and-juicypotatong-privilege-escalation-tool
Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.
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