Encrypting Files with WinRar or 7z
Elastic Stack Serverless Security
Identifies use of WinRar or 7z to create an encrypted files. Adversaries will often compress and encrypt data in preparation for exfiltration.
Rule type: eql
Rule indices:
- logs-endpoint.events.*
- winlogbeat-*
- logs-windows.*
Severity: medium
Risk score: 47
Runs every: 5m
Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Collection
Version: 4
Rule authors:
- Elastic
Rule license: Elastic License v2
process where event.type in ("start", "process_started") and
((process.name:"rar.exe" or process.code_signature.subject_name == "win.rar GmbH" or
process.pe.original_file_name == "Command line RAR") and
process.args == "a" and process.args : ("-hp*", "-p*", "-dw", "-tb", "-ta", "/hp*", "/p*", "/dw", "/tb", "/ta"))
or
(process.pe.original_file_name in ("7z.exe", "7za.exe") and
process.args == "a" and process.args : ("-p*", "-sdel"))
/* uncomment if noisy for backup software related FPs */
/* not process.parent.executable : ("C:\\Program Files\\*.exe", "C:\\Program Files (x86)\\*.exe") */
Framework: MITRE ATT&CKTM
Tactic:
- Name: Collection
- ID: TA0009
- Reference URL: https://attack.mitre.org/tactics/TA0009/
Technique:
- Name: Archive Collected Data
- ID: T1560
- Reference URL: https://attack.mitre.org/techniques/T1560/
Sub-technique:
- Name: Archive via Utility
- ID: T1560.001
- Reference URL: https://attack.mitre.org/techniques/T1560/001/