Malicious PowerShell Download of FortiEndpoint Patch Masquerade via EKZ Stealer

ATT&CK techniques

Execution → C2

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule detects PowerShell using WebClient DownloadFile to retrieve a payload named FortiEndpoint_Patch.exe into ProgramData. This masquerade is used after exploitation of Fortinet CVE-2026-35616 to stage the EKZ Stealer while posing as a security patch. Downloading a fake endpoint patch via PowerShell indicates active post-exploitation tooling.

Reporting behind it

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Suspicious PowerShell Download of Disguised Payload to ProgramData

Suspicious PowerShell WebClient Download of Executable Payload

Suspicious PowerShell Remote Script Execution via IEX DownloadString

Suspicious PowerShell Download Cradle to Blogspot (via process_creation)

Suspicious Hidden PowerShell WebClient DownloadFile Cradle

Malicious PowerShell Download of FortiEndpoint Patch Masquerade via EKZ Stealer

Pivot detection · T1059.001 · 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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