Suspicious Antimalware Scan Interface DLL
editSuspicious Antimalware Scan Interface DLL
editIdentifies the creation of the Antimalware Scan Interface (AMSI) DLL in an unusual location. This may indicate an attempt to bypass AMSI by loading a rogue AMSI module instead of the legit one.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
- endgame-*
Severity: high
Risk score: 73
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
- Elastic Endgame
Version: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Rule query
editfile where event.action != "deletion" and file.path != null and
file.name : ("amsi.dll", "amsi") and not file.path : ("?:\\Windows\\system32\\amsi.dll", "?:\\Windows\\Syswow64\\amsi.dll")
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Impair Defenses
- ID: T1562
- Reference URL: https://attack.mitre.org/techniques/T1562/
-
Sub-technique:
- Name: Disable or Modify Tools
- ID: T1562.001
- Reference URL: https://attack.mitre.org/techniques/T1562/001/
-
Technique:
- Name: Hijack Execution Flow
- ID: T1574
- Reference URL: https://attack.mitre.org/techniques/T1574/
-
Sub-technique:
- Name: DLL Search Order Hijacking
- ID: T1574.001
- Reference URL: https://attack.mitre.org/techniques/T1574/001/