Malicious Curl MSI Download to ProgramData via Process Creation
- Product
- windows
- Category
- process_creation
- Author
- HuntRule
- Published
- 2026-09-12
- Updated
- 2026-09-12
ATT&CK techniques
C2Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
Exfiltration
Impact
What it detects
This rule detects curl.exe downloading a Windows Installer package into the ProgramData directory, the payload staging behavior of the Chaos ransomware msaRAT loader reported by Cisco Talos. The tool fetches update_ms.msi from an attacker IP and writes it to ProgramData before execution. Detecting this retrieval catches ingress of the MSI that unpacks the covert browser-based C2 implant.
Reporting behind it
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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