Python Path Configuration File Creation - Linux

Status: test
Severity: medium
Log source: product linux, category file_event
Author: Andreas Braathen (mnemonic.io)
Source: github.com/SigmaHQ/sigma

Detects creation of a Python path configuration file (.pth) in Python library folders, which can be maliciously abused for code execution and persistence. Modules referenced by these files are run at every Python startup (v3.5+), regardless of whether the module is imported by the calling script. Default paths are '\lib\site-packages*.pth' (Windows) and '/lib/pythonX.Y/site-packages/*.pth' (Unix and macOS).

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.006` Command and Scripting Interpreter: Python

Event coverage

Provider	Event
Sysmon-for-Linux	Event ID 11

Rule body yaml

title: Python Path Configuration File Creation - Linux
id: fb96c26c-9f85-4ae7-af0d-ed1ed1f1f5ce
related:
    - id: e3652ba3-0ad8-4010-a957-b7ba369e7bac # Windows
      type: similar
    - id: 4f394635-13ef-4599-b677-3353e0f84f55 # MacOS
      type: similar
status: test
description: |
    Detects creation of a Python path configuration file (.pth) in Python library folders, which can be maliciously abused for code execution and persistence.
    Modules referenced by these files are run at every Python startup (v3.5+), regardless of whether the module is imported by the calling script.
    Default paths are '\lib\site-packages\*.pth' (Windows) and '/lib/pythonX.Y/site-packages/*.pth' (Unix and macOS).
references:
    - https://www.volexity.com/blog/2024/04/12/zero-day-exploitation-of-unauthenticated-remote-code-execution-vulnerability-in-globalprotect-cve-2024-3400/
    - https://www.virustotal.com/gui/file/3de2a4392b8715bad070b2ae12243f166ead37830f7c6d24e778985927f9caac
    - https://docs.python.org/3/library/site.html
author: Andreas Braathen (mnemonic.io)
date: 2024-04-25
tags:
    - attack.execution
    - attack.t1059.006
    - detection.threat-hunting
logsource:
    product: linux
    category: file_event
detection:
    selection:
        TargetFilename|re: '(?i)/lib/python3\.([5-9]|[0-9]{2})/site-packages/' # Unix and macOS
        TargetFilename|endswith: '.pth'
    condition: selection
falsepositives:
    - Although .pth files are discouraged due to potential security implications, these are legitimate files by specification.
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    TargetFilename|re: '(?i)/lib/python3\.([5-9]|[0-9]{2})/site-packages/'
    TargetFilename|endswith: '.pth'

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
`TargetFilename`	ends_with	`.pth`
`TargetFilename`	regex_match	`(?i)/lib/python3.([5-9]\|[0-9]{2})/site-packages/`

`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)

Python Path Configuration File Creation - Linux

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Indicators

Keyboard shortcuts

Search operators

Python Path Configuration File Creation - Linux

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`