Attempt to Remove File Quarantine Attribute

Identifies a potential Gatekeeper bypass. In macOS, when applications or programs are downloaded from the internet, there is a quarantine flag set on the file. This attribute is read by Apple’s Gatekeeper defense program at execution time. An adversary may disable this attribute to evade defenses.

Rule type: eql

Rule indices:

auditbeat-*
logs-endpoint.events.*

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
macOS
Threat Detection
Defense Evasion

Version: 6

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

edit

Rule query

edit

process where event.type in ("start", "process_started") and
  process.name : "xattr" and
  (
    (process.args : "com.apple.quarantine" and process.args : ("-d", "-w")) or
    (process.args : "-c") or
    (process.command_line : ("/bin/bash -c xattr -c *", "/bin/zsh -c xattr -c *", "/bin/sh -c xattr -c *"))
  ) and not process.args_count > 12

Framework: MITRE ATT&CK^TM

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/

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