ruby.lang.security.dangerous-open3-pipeline.dangerous-open3-pipeline

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Detected non-static command inside $PIPE. Audit the input to '$PIPE'. If unverified user data can reach this call site, this is a code injection vulnerability. A malicious actor can inject a malicious script to execute arbitrary code.

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Defintion

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rules:
  - id: dangerous-open3-pipeline
    patterns:
      - pattern: |
          Open3.$PIPE(...)
      - pattern-not: |
          Open3.$PIPE(...,"...",...)
      - metavariable-regex:
          metavariable: $PIPE
          regex: ^(pipeline|pipeline_r|pipeline_rw|pipeline_start|pipeline_w)$
    message: Detected non-static command inside $PIPE. Audit the input to '$PIPE'.
      If unverified user data can reach this call site, this is a code injection
      vulnerability. A malicious actor can inject a malicious script to execute
      arbitrary code.
    metadata:
      cwe:
        - "CWE-94: Improper Control of Generation of Code ('Code Injection')"
      owasp:
        - A03:2021 - Injection
      category: security
      technology:
        - ruby
      references:
        - https://owasp.org/Top10/A03_2021-Injection
      cwe2022-top25: true
      subcategory:
        - audit
      likelihood: LOW
      impact: HIGH
      confidence: LOW
      license: Commons Clause License Condition v1.0[LGPL-2.1-only]
      vulnerability_class:
        - Code Injection
    severity: WARNING
    languages:
      - ruby

Examples

dangerous-open3-pipeline.rb

require 'open3'

fname = "/usr/share/man/man1/ruby.1.gz"
# ok:dangerous-open3-pipeline
p Open3.pipeline(["zcat", fname], "nroff -man", "less")

fname = "/usr/share/man/man1/ls.1.gz"
# ok:dangerous-open3-pipeline
Open3.pipeline(["zcat", fname], "nroff -man", "colcrt")

# ok:dangerous-open3-pipeline
Open3.pipeline("sort", "uniq -c", :in=>"names.txt", :out=>"count")

r,w = IO.pipe
w.print "ibase=14\n10\n"
# ok:dangerous-open3-pipeline
Open3.pipeline("bc", "tee /dev/tty", :in=>r, :out=>w)

pdf_file = "paper.pdf"
# ruleid:dangerous-open3-pipeline
Open3.pipeline(["pdftops", pdf_file, "-"], ["lpr", "-P#{user_input}"])