python.lang.security.audit.dangerous-spawn-process-audit.dangerous-spawn-process-audit

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Found dynamic content when spawning a process. This is dangerous if external data can reach this function call because it allows a malicious actor to execute commands. Ensure no external data reaches here.
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Defintion
rules:
- id: dangerous-spawn-process-audit
message: Found dynamic content when spawning a process. This is dangerous if
external data can reach this function call because it allows a malicious
actor to execute commands. Ensure no external data reaches here.
metadata:
source-rule-url: https://bandit.readthedocs.io/en/latest/plugins/b605_start_process_with_a_shell.html
cwe:
- "CWE-78: Improper Neutralization of Special Elements used in an OS
Command ('OS Command Injection')"
owasp:
- A01:2017 - Injection
- A03:2021 - Injection
references:
- https://semgrep.dev/docs/cheat-sheets/python-command-injection/
asvs:
section: "V5: Validation, Sanitization and Encoding Verification Requirements"
control_id: 5.3.8 OS Command Injection
control_url: https://github.com/OWASP/ASVS/blob/master/4.0/en/0x13-V5-Validation-Sanitization-Encoding.md#v53-output-encoding-and-injection-prevention-requirements
version: "4"
category: security
technology:
- python
confidence: LOW
cwe2022-top25: true
cwe2021-top25: true
subcategory:
- audit
likelihood: LOW
impact: HIGH
license: Commons Clause License Condition v1.0[LGPL-2.1-only]
languages:
- python
severity: ERROR
pattern-either:
- patterns:
- pattern-not: os.$METHOD($MODE, "...", ...)
- pattern: os.$METHOD(...)
- metavariable-regex:
metavariable: $METHOD
regex: (spawnl|spawnle|spawnlp|spawnlpe|spawnv|spawnve|spawnvp|spawnvp|spawnvpe|posix_spawn|posix_spawnp|startfile)
- patterns:
- pattern-not: os.$METHOD($MODE, "...", ["...","...",...], ...)
- pattern: os.$METHOD($MODE, $BASH, ["-c",$CMD,...],...)
- metavariable-regex:
metavariable: $METHOD
regex: (spawnv|spawnve|spawnvp|spawnvp|spawnvpe|posix_spawn|posix_spawnp)
- metavariable-regex:
metavariable: $BASH
regex: (.*)(sh|bash|ksh|csh|tcsh|zsh)
- patterns:
- pattern-not: os.$METHOD($MODE, "...", "...", "...", ...)
- pattern: os.$METHOD($MODE, $BASH, "-c", $CMD,...)
- metavariable-regex:
metavariable: $METHOD
regex: (spawnl|spawnle|spawnlp|spawnlpe)
- metavariable-regex:
metavariable: $BASH
regex: (.*)(sh|bash|ksh|csh|tcsh|zsh)
Examples
dangerous-spawn-process-audit.py
import os
import shlex
from somewhere import something
# ok:dangerous-spawn-process-audit
os.spawnlp(os.P_WAIT, "ls")
# ok:dangerous-spawn-process-audit
os.spawnlpe(os.P_WAIT, "ls")
# ok:dangerous-spawn-process-audit
os.spawnv(os.P_WAIT, "/bin/ls")
# ok:dangerous-spawn-process-audit
os.spawnve(os.P_WAIT, "/bin/ls", ["-a"], os.environ)
# ruleid:dangerous-spawn-process-audit
os.spawnlp(os.P_WAIT, something())
# ruleid:dangerous-spawn-process-audit
os.spawnlpe(os.P_WAIT, something())
# ruleid:dangerous-spawn-process-audit
os.spawnv(os.P_WAIT, something())
# ruleid:dangerous-spawn-process-audit
os.spawnve(os.P_WAIT, something(), ["-a"], os.environ)
# ruleid:dangerous-spawn-process-audit
os.spawnve(os.P_WAIT, "/bin/bash", ["-c", something()], os.environ)
# ruleid:dangerous-spawn-process-audit
os.spawnl(os.P_WAIT, "/bin/bash", "-c", something())
def run_payload(shell_command: str) -> None:
args = shlex.split(shell_command)
path = args[0]
# ruleid:dangerous-spawn-process-audit
pid = os.posix_spawn(path, args, os.environ)
os.waitpid(pid, 0)
Short Link: https://sg.run/lK0y