Malicious Fileless JavaScript Execution via Deno Data URI (via process_creation)

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.007JavaScript
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the Deno runtime executing an inline base64 encoded JavaScript payload passed as a data application javascript URI, a fileless execution technique used by attackers abusing alternative runtime environments to evade disk based detection. The allow all flag combined with an inline data URI is a strong indicator of malicious in memory code execution.

Reporting behind it

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Malicious Fileless JavaScript Execution via Deno Data URI (via process_creation)

Pivot detection · T1027 · 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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