Malicious IIS Worker Process Spawning conn.exe Web Shell Child by APT41 (via process_creation)

ATT&CK techniques

Persistence

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1505.003Web Shell
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 a masqueraded conn.exe child process, a pattern consistent with APT41 web shell command execution on compromised web servers. A web server process launching arbitrary tooling is a strong indicator of an installed web shell.

Reporting behind it

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Malicious IIS Worker Process Spawning conn.exe Web Shell Child by APT41 (via process_creation)

Pivot detection · T1505.003 · 9 related

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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