Sigma rule: Atomic MacOS Stealer - FileGrabber Activity

Rule

Title

Atomic MacOS Stealer - FileGrabber Activity

Status

experimental

Level

high

Author

Jason Phang Vern - Onn, Robbin Ooi Zhen Heng (Gen Digital)

Date

2025-11-22

File

rules-emerging-threats/2025/Malware/Atomic-MacOS-Stealer/proc_creation_macos_malware_amos_curl_post.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

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.

Log source

product

macos

category

process_creation

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_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.execution
• attack.t1059.002
• detection.emerging-threats

MITRE ATT&CK ids this rule names

• T1059.002

Related rules

• e710a880-1f18-4417-b6a0-b5afdf7e305a (obsolete)

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/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2025/Malware/Atomic-MacOS-Stealer/proc_creation_macos_malware_amos_curl_post.yml