CVE-2022-0122: Digitalbazaar Forge URL Redirection Flaw

CVE-2022-0122 Overview

CVE-2022-0122 is a URL Redirection to Untrusted Site vulnerability (CWE-601) affecting the DigitalBazaar Forge library, a popular JavaScript cryptography library used in Node.js applications. This open redirect vulnerability in the forge.util.parseUrl function could allow attackers to redirect users to malicious websites, potentially enabling phishing attacks or credential theft.

Critical Impact

Applications using the vulnerable parseUrl function may inadvertently redirect users to attacker-controlled websites, facilitating phishing campaigns and social engineering attacks.

Affected Products

• digitalbazaar forge (Node.js package)
• Applications using forge.util.parseUrl for URL handling
• Systems relying on Forge for HTTP client URL parsing

Discovery Timeline

• 2022-01-06 - CVE CVE-2022-0122 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-0122

Vulnerability Analysis

The vulnerability exists in the forge.util.parseUrl function within the Forge library. This function was designed to parse the scheme, host, and port from HTTP(S) URLs using a regular expression. However, the regex pattern used for URL parsing was flawed, as noted in the code comment stating "FIXME: this regex looks a bit broken."

The broken regex pattern /^(https?):\\/\\/([^:&^\\/]*):?(\\d*)(.*)$/g failed to properly validate and sanitize URL inputs, allowing malicious URLs to be processed in unexpected ways. This could lead to open redirect vulnerabilities where user-supplied URLs are not properly validated before redirecting users.

The vulnerability can be exploited without authentication and requires user interaction (such as clicking a malicious link). If successful, the attacker can redirect victims from a trusted application to a malicious site, potentially compromising confidentiality and integrity of user data through phishing or credential harvesting attacks.

Root Cause

The root cause of this vulnerability is the use of a flawed regular expression in forge.util.parseUrl that does not properly validate URL inputs. The custom URL parsing implementation failed to handle edge cases and malicious inputs correctly, allowing URL manipulation that could result in open redirects. Additionally, the code maintained its own URL parsing logic rather than relying on well-tested browser or Node.js native URL parsing APIs.

Attack Vector

An attacker can exploit this vulnerability by crafting malicious URLs that bypass the flawed regex validation. When a vulnerable application uses forge.util.parseUrl to process user-controlled URLs and subsequently redirects users based on the parsed output, attackers can manipulate the destination to point to malicious sites.

The attack vector is network-based, requiring user interaction such as clicking a crafted link. Successful exploitation enables cross-site redirect attacks, which can be used for:

• Phishing attacks impersonating legitimate services
• Credential theft through fake login pages
• Malware distribution through malicious redirects

// Vulnerable code removed from lib/util.js
// The parseUrl function used a broken regex for URL parsing
util.parseUrl = function(str) {
  // FIXME: this regex looks a bit broken
  var regex = /^(https?):\\/\\/([^:&^\\/]*):?(\\d*)(.*)$/g;
  regex.lastIndex = 0;
  var m = regex.exec(str);
  var url = (m === null) ? null : {
    full: str,
    scheme: m[1],
    host: m[2],
    port: m[3],
    path: m[4]
  };
  // ...
}

Source: GitHub Commit Reference

Detection Methods for CVE-2022-0122

Indicators of Compromise

• Unusual redirect patterns in web application logs pointing to external domains
• User reports of being redirected to unexpected or suspicious websites
• HTTP referrer headers showing redirects from your application to known malicious domains
• Increased phishing reports from users who visited links associated with your application

Detection Strategies

• Review application code for usage of forge.util.parseUrl function calls
• Implement URL validation logging to detect malformed or suspicious redirect attempts
• Deploy web application firewalls (WAF) with rules to detect open redirect attack patterns
• Use static code analysis tools to identify vulnerable Forge library versions in dependencies

Monitoring Recommendations

• Monitor HTTP 302/301 redirect responses for unexpected external destinations
• Set up alerts for high volumes of redirect requests to external domains
• Implement Content Security Policy (CSP) headers to restrict redirect destinations
• Track and audit all URL parsing operations in security-sensitive contexts

How to Mitigate CVE-2022-0122

Immediate Actions Required

• Update the Forge library to the patched version that removes the vulnerable parseUrl function
• Audit application code for any direct usage of forge.util.parseUrl and replace with secure alternatives
• Implement server-side URL validation using allowlists for permitted redirect destinations
• Review and update any URL handling logic that depends on the Forge library

Patch Information

The vulnerability was addressed by DigitalBazaar in commit db8016c805371e72b06d8e2edfe0ace0df934a5e. The fix removes the vulnerable forge.util.parseUrl function entirely and updates the HTTP client code to use the native URL API properties (protocol, hostname) instead of the custom parsed values (scheme, host).

The patch modifies lib/http.js to use standard URL object properties:

// Patched code in lib/http.js - uses native URL API
return 'forge.http.' +
  client.url.protocol.slice(0, -1) + '.' +
  client.url.hostname + '.' +
  client.url.port;

Source: GitHub Commit Reference

Workarounds

• Avoid using forge.util.parseUrl and use the native URL constructor in JavaScript instead
• Implement input validation with URL allowlists before processing user-supplied URLs
• Add redirect confirmation pages that warn users before navigating to external sites
• Apply strict URL validation using the built-in Node.js url module or browser URL API

# Update forge package to latest version
npm update node-forge
# Or install specific patched version
npm install node-forge@latest