Suspicious Execution from a Mounted Deviceedit
Identifies when a script interpreter or signed binary is launched via a non-standard working directory. An attacker may use this technique to evade defenses.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
Severity: medium
Risk score: 47
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
Version: 2
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guideedit
## Config If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
Rule queryedit
process where event.type == "start" and process.executable : "C:\\*" and
(process.working_directory : "?:\\" and not process.working_directory: "C:\\") and
process.parent.name : "explorer.exe" and
process.name : ("rundll32.exe", "mshta.exe", "powershell.exe", "pwsh.exe", "cmd.exe", "regsvr32.exe",
"cscript.exe", "wscript.exe")
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Signed Binary Proxy Execution
- ID: T1218
- Reference URL: https://attack.mitre.org/techniques/T1218/
-
Sub-technique:
- Name: Mshta
- ID: T1218.005
- Reference URL: https://attack.mitre.org/techniques/T1218/005/
-
Sub-technique:
- Name: Regsvr32
- ID: T1218.010
- Reference URL: https://attack.mitre.org/techniques/T1218/010/
-
Sub-technique:
- Name: Rundll32
- ID: T1218.011
- Reference URL: https://attack.mitre.org/techniques/T1218/011/
-
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
-
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
-
Sub-technique:
- Name: PowerShell
- ID: T1059.001
- Reference URL: https://attack.mitre.org/techniques/T1059/001/