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: 5 minutes

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: 3 (version history)

Added (Elastic Stack release): 7.11.0

Last modified (Elastic Stack release): 7.12.0

Rule authors: Elastic

Rule license: Elastic License v2

Rule query

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process where event.type in ("start", "process_started") and
process.args : "xattr" and ( (process.args :
"com.apple.quarantine" and process.args : ("-d", "-w")) or
(process.args : "-c" and process.command_line : (
"/bin/bash -c xattr -c *", "/bin/zsh -c xattr -c *",
"/bin/sh -c xattr -c *" ) ) )

Threat mapping

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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/

Rule version history

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Version 3 (7.12.0 release)

Updated query, changed from:

process where event.type in ("start", "process_started") and
process.name == "xattr" and process.args == "com.apple.quarantine" and
process.args == "-d"

Version 2 (7.11.2 release)

Formatting only

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