Detection rules › Sigma
Atomic MacOS Stealer - FileGrabber Activity
Detects suspicious activity associated with Atomic MacOS Stealer (Amos) campaigns, including execution of FileGrabber and curl-based POST requests used for data exfiltration. The rule identifies either the execution of FileGrabber targeting /tmp or the use of curl to POST sensitive user data (including files such as /tmp/out.zip) to remote servers, which are key indicators of Amos infostealer activity.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1059.002 Command and Scripting Interpreter: AppleScript |
Event coverage
| Provider | Event | Title |
|---|---|---|
| ESF | exec | Process Execution (Notify) |
Rule body yaml
title: Atomic MacOS Stealer - FileGrabber Activity
id: e710a880-1f18-4417-b6a0-b5afdf7e33da
related:
- id: e710a880-1f18-4417-b6a0-b5afdf7e305a
type: obsolete
status: experimental
description: |
Detects suspicious activity associated with Atomic MacOS Stealer (Amos) campaigns, including execution of FileGrabber and curl-based POST requests used for data exfiltration. The rule identifies either the execution of FileGrabber targeting /tmp or the use of curl to POST sensitive user data (including files such as /tmp/out.zip) to remote servers, which are key indicators of Amos infostealer activity.
references:
- https://www.trendmicro.com/en_us/research/25/i/an-mdr-analysis-of-the-amos-stealer-campaign.html
- https://hunt.io/blog/macos-clickfix-applescript-terminal-phishing
- https://github.com/bobby-tablez/TTP-Threat-Feeds/blob/45398914e631f8372c3a9fbcd339ff65ffff1b17/results/2025/10/20251001-161956-trendmicro-atomic-macos-stealer-(amos).yml#L36
- https://www.jamf.com/blog/infostealers-pose-threat-to-macos/
author: Jason Phang Vern - Onn, Robbin Ooi Zhen Heng (Gen Digital)
date: 2025-11-22
tags:
- attack.execution
- attack.t1059.002
- detection.emerging-threats
logsource:
category: process_creation
product: macos
detection:
selection_curl_post:
CommandLine|contains|all:
- 'curl'
- 'POST'
- 'user:'
- '-H '
- 'BuildID'
- 'file=@/tmp/out.zip'
- 'cl: 0'
selection_filegrabber_exec:
CommandLine|contains|all:
- 'FileGrabber'
- '/tmp'
condition: 1 of selection_*
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
1 of selection_*Stage 1: selection_curl_post
selection_curl_post:
CommandLine|contains|all:
- 'curl'
- 'POST'
- 'user:'
- '-H '
- 'BuildID'
- 'file=@/tmp/out.zip'
- 'cl: 0'
Stage 2: selection_filegrabber_exec
selection_filegrabber_exec:
CommandLine|contains|all:
- 'FileGrabber'
- '/tmp'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|