Github Self-Hosted Runner Execution

Status: test
Severity: medium
Log source: product windows, category process_creation
Author: Daniel Koifman (KoifSec)
Source: github.com/SigmaHQ/sigma

Detects GitHub self-hosted runners executing workflows on local infrastructure that could be abused for persistence and code execution. Shai-Hulud is an npm supply chain worm targeting CI/CD environments. It installs runners on compromised systems to maintain access after credential theft, leveraging their access to secrets and internal networks.

MITRE ATT&CK coverage

Tactic	Techniques
Command & Control	`T1071` Application Layer Protocol, `T1102.002` Web Service: Bidirectional Communication

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Github Self-Hosted Runner Execution
id: 5bac7a56-da88-4c27-922e-c81e113b20cb
status: test
description: |
    Detects GitHub self-hosted runners executing workflows on local infrastructure that could be abused for persistence and code execution.
    Shai-Hulud is an npm supply chain worm targeting CI/CD environments.
    It installs runners on compromised systems to maintain access after credential theft, leveraging their access to secrets and internal networks.
references:
    - https://about.gitlab.com/blog/gitlab-discovers-widespread-npm-supply-chain-attack/
    - https://securitylabs.datadoghq.com/articles/shai-hulud-2.0-npm-worm/
author: Daniel Koifman (KoifSec)
date: 2025-11-29
tags:
    - attack.command-and-control
    - attack.t1102.002
    - attack.t1071
logsource:
    category: process_creation
    product: windows
detection:
    selection_worker_img:  # Example command C:\Users\Lab\actions-runner\bin\Runner.Worker.exe spawnclient 1288 1252
        - Image|endswith: '\Runner.Worker.exe'
        - OriginalFileName: 'Runner.Worker.dll'
    selection_worker_cli:
        CommandLine|contains: 'spawnclient'
    selection_listener_img: # Example command C:\Users\Lab\actions-runner\bin\Runner.Listener.exe  configure --url https://github.com/ABC/ABC --token 123123
        - Image|endswith: '\Runner.Listener.exe'
        - OriginalFileName: 'Runner.Listener.dll'
    selection_listener_cli:
        CommandLine|contains:
            - 'run'
            - 'configure'
    condition: all of selection_worker_* or all of selection_listener_*
falsepositives:
    - Legitimate GitHub self-hosted runner installations on designated CI/CD infrastructure
    - Authorized runner deployments by DevOps/Platform teams following change management
    - Scheduled runner updates or reconfigurations on existing build agents
    - Self-hosted runners that follow expected/known naming patterns
    - Installation via expected/known configuration management tools (reflected mostly as parent process name)
level: medium
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_github_self_hosted_runner/info.yml

Stages and Predicates

Stage 0: `condition`

all of selection_worker_* or all of selection_listener_*

Stage 1: `selection_worker_img`

selection_worker_img:
    - Image|endswith: '\Runner.Worker.exe'
    - OriginalFileName: 'Runner.Worker.dll'

Stage 2: `selection_worker_cli`

selection_worker_cli:
    CommandLine|contains: 'spawnclient'

Stage 3: `selection_listener_img`

selection_listener_img:
    - Image|endswith: '\Runner.Listener.exe'
    - OriginalFileName: 'Runner.Listener.dll'

Stage 4: `selection_listener_cli`

selection_listener_cli:
    CommandLine|contains:
        - 'run'
        - 'configure'

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	`configure` `run` corpus 3 (splunk 2, sigma 1) `spawnclient`
`Image`	ends_with	`\Runner.Listener.exe` `\Runner.Worker.exe`
`OriginalFileName`	eq	`Runner.Listener.dll` `Runner.Worker.dll`

`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)

Github Self-Hosted Runner Execution

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_worker_img`

Stage 2: `selection_worker_cli`

Stage 3: `selection_listener_img`

Stage 4: `selection_listener_cli`

Indicators

Keyboard shortcuts

Search operators

Github Self-Hosted Runner Execution

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_worker_img

Stage 2: selection_worker_cli

Stage 3: selection_listener_img

Stage 4: selection_listener_cli

Indicators

Stage 0: `condition`

Stage 1: `selection_worker_img`

Stage 2: `selection_worker_cli`

Stage 3: `selection_listener_img`

Stage 4: `selection_listener_cli`