CVE-2021-42740 : What You Need to Know

The shell-quote package before 1.7.3 for Node.js is susceptible to command injection through a regex vulnerability.

Understanding CVE-2021-42740

What is CVE-2021-42740?

The CVE-2021-42740 vulnerability in shell-quote package allows attackers to inject arbitrary commands through a regex vulnerability aimed at supporting Windows drive letters.

The Impact of CVE-2021-42740

This vulnerability can be exploited to inject unescaped shell metacharacters, potentially leading to command injection attacks if the output is passed to a real shell as a quoted argument.

Technical Details of CVE-2021-42740

Vulnerability Description

The issue arises from an incorrect Windows drive letter regex character class ({A-z] instead of {A-Za-z]), enabling the insertion of various shell metacharacters, including the backtick character.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: Before 1.7.3

Exploitation Mechanism

The vulnerability can be exploited by passing the package output to a shell command using exec(), allowing an attacker to execute malicious commands.

Mitigation and Prevention

Immediate Steps to Take

Update the shell-quote package to version 1.7.3 or later.
Avoid passing untrusted inputs to shell commands.

Long-Term Security Practices

Regularly monitor and update dependencies for known vulnerabilities.

Patching and Updates

Apply patches promptly and stay informed about security updates.