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:

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:

Version: 7

Rule authors:

Rule license: Elastic License v2

## Setup

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.

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