CVE-2021-42740

Description

The shell-quote package before 1.7.3 for Node.js allows command injection. An attacker can inject unescaped shell metacharacters through a regex designed to support Windows drive letters. If the output of this package is passed to a real shell as a quoted argument to a command with exec(), an attacker can inject arbitrary commands. This is because the Windows drive letter regex character class is {A-z] instead of the correct {A-Za-z]. Several shell metacharacters exist in the space between capital letter Z and lower case letter a, such as the backtick character.

CVSS Metrics

• v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• v2.0•HIGH•Score: 7.5AV:N/AC:L/Au:N/C:P/I:P/A:P

EPSS Trends

Current EPSS score: 9.04%• Percentile: 93%

Techniques & Countermeasures

• CWE-77•Improper Neutralization of Special Elements used in a Command ('Command Injection')

  The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Affected Systems

• Npm•shell-quote

  ≥ 1.6.3, < 1.7.3

• shell-quote_project•shell-quote

  < 1.7.3

References (7)

• https://www.npmjs.com/package/shell-quote
• https://github.com/substack/node-shell-quote/blob/master/CHANGELOG.md#173
• https://github.com/substack/node-shell-quote/commit/5799416ed454aa4ec9afafc895b4e31760ea1abe
• https://nvd.nist.gov/vuln/detail/CVE-2021-42740
• https://github.com/ljharb/shell-quote/commit/5799416ed454aa4ec9afafc895b4e31760ea1abe
• https://github.com/ljharb/shell-quote
• https://github.com/ljharb/shell-quote/blob/master/CHANGELOG.md#173