Suspicious Ousaban Installation Marker maisum.dat Created (via file_event)

ATT&CK techniques

Persistence → Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1547.001Registry Run Keys / Startup Folder
Priv Esc
- T1547.001Registry Run Keys / Startup Folder
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the Ousaban banking trojan dropping its empty installation marker file maisum.dat whose creation time records the infection timestamp alongside the payload directory. Creation of this specific marker file indicates a successful install. The trojan then persists through a Run key.

Reporting behind it

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Suspicious Ousaban Installation Marker maisum.dat Created (via file_event)

Pivot detection · T1547.001 · 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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