Masquerading PNGPlug DLL Sideloading of libcef Into down.exe Host Binary (via image_load)

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1574.001DLL
Persistence
- T1574.001DLL
Priv Esc
- T1574.001DLL
Defense Evasion
- T1574.001DLL
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the down.exe host binary loading a libcef.dll from the PNGPlug delivery archive, a DLL sideloading step that decrypts and injects the ValleyRAT payload hidden inside PNG-masqueraded files. Pairing this common legitimate application name with the CEF library load surfaces the sideloading behavior at the point of second-stage execution.

Reporting behind it

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Masquerading PNGPlug DLL Sideloading of libcef Into down.exe Host Binary (via image_load)

Pivot detection · T1574.001 · 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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