Suspicious MSBuild Execution Spawned by PowerShell via PhantomVAI Loader (via process_creation)

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.001PowerShell
Persistence
Priv Esc
- T1055.012Process Hollowing
Defense Evasion
- T1055.012Process Hollowing
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects MSBuild launched as a child of PowerShell, the final stage of the PhantomVAI loader chain that injects infostealer code into the trusted Microsoft build utility. MSBuild is abused as a signed process host to evade defenses. Detecting this parent-child relationship exposes process injection delivering commodity infostealers.

Reporting behind it

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Suspicious MSBuild Execution Spawned by PowerShell via PhantomVAI Loader (via process_creation)

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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