CVE-2024-45590: Openjsf Body-parser DoS Vulnerability

CVE-2024-45590 Overview

CVE-2024-45590 is a denial of service vulnerability affecting body-parser, a popular Node.js body parsing middleware used extensively in Express.js applications. When URL encoding is enabled, versions prior to 1.20.3 are vulnerable to resource exhaustion attacks that can render servers unresponsive. A malicious actor can exploit this vulnerability using specially crafted payloads to flood the server with a large number of requests, resulting in service disruption for legitimate users.

Critical Impact

This vulnerability enables attackers to cause denial of service conditions on Node.js web applications using body-parser with URL encoding enabled, potentially affecting critical business operations and user accessibility.

Affected Products

• openjsf body-parser versions prior to 1.20.3
• Node.js applications using vulnerable body-parser middleware
• Express.js applications with URL-encoded body parsing enabled

Discovery Timeline

• 2024-09-10 - CVE CVE-2024-45590 published to NVD
• 2024-09-20 - Last updated in NVD database

Technical Details for CVE-2024-45590

Vulnerability Analysis

This vulnerability falls under CWE-405 (Asymmetric Resource Consumption), which describes scenarios where an attacker can consume disproportionate server resources relative to the effort required to initiate an attack. The body-parser middleware, which handles incoming request bodies in Express.js applications, contains a flaw in its URL encoding processing logic. When URL encoding is enabled, the middleware does not properly handle certain malformed or specially crafted payloads, leading to excessive resource consumption.

The vulnerability is particularly concerning because body-parser is one of the most widely used middleware components in the Node.js ecosystem. It processes incoming HTTP request bodies before application handlers, meaning exploitation can impact applications before any business logic executes.

Root Cause

The root cause lies in how body-parser processes URL-encoded request bodies. When handling specially crafted payloads, the parser enters a state where it consumes excessive CPU cycles or memory, creating an amplification effect. This asymmetric resource consumption allows attackers to exhaust server resources with relatively minimal effort, triggering denial of service conditions. The fix implemented in version 1.20.3 addresses this by adding proper input validation and resource constraints during URL-encoded body parsing.

Attack Vector

The attack vector is network-based and does not require authentication or user interaction. An attacker can remotely target any publicly accessible Node.js application using a vulnerable version of body-parser with URL encoding enabled. The attack involves sending HTTP requests with specially crafted URL-encoded bodies that trigger the inefficient parsing behavior.

The attacker sends multiple malformed requests designed to maximize resource consumption on the target server. As the server struggles to process these requests, legitimate traffic is starved of resources, effectively denying service to valid users. The attack can be sustained with relatively low bandwidth requirements from the attacker's side due to the asymmetric nature of the resource consumption.

Detection Methods for CVE-2024-45590

Indicators of Compromise

• Unusual spike in HTTP POST requests with URL-encoded content types
• Increased CPU utilization on Node.js processes without corresponding increase in legitimate traffic
• Application response time degradation or timeout errors
• Memory exhaustion alerts on servers running body-parser middleware

Detection Strategies

• Monitor Node.js application logs for timeout errors or unresponsive worker processes
• Implement rate limiting at the load balancer or reverse proxy layer to detect abnormal request patterns
• Use dependency scanning tools to identify applications running body-parser versions below 1.20.3
• Deploy application performance monitoring (APM) to detect anomalous resource consumption patterns

Monitoring Recommendations

• Configure alerts for CPU and memory spikes on Node.js application servers
• Implement request rate monitoring to detect flood attack patterns
• Enable logging for requests with unusually large or malformed URL-encoded bodies
• Monitor network traffic for sustained high-volume POST request patterns targeting API endpoints

How to Mitigate CVE-2024-45590

Immediate Actions Required

• Upgrade body-parser to version 1.20.3 or later immediately
• Review all Node.js applications to identify those using vulnerable body-parser versions
• Implement rate limiting to reduce the impact of potential exploitation attempts
• Consider temporarily disabling URL-encoded body parsing if not required for application functionality

Patch Information

The vulnerability has been patched in body-parser version 1.20.3. The fix is available in the GitHub commit b2695c4450f06ba3b0ccf48d872a229bb41c9bce. Organizations should update their package.json or package-lock.json files to specify the patched version and run dependency updates. For additional details, refer to the GitHub Security Advisory GHSA-qwcr-r2fm-qrc7.

Workarounds

• Implement request body size limits at the reverse proxy or web server level
• Deploy web application firewall (WAF) rules to filter malicious URL-encoded payloads
• Use rate limiting to throttle requests from individual IP addresses
• Consider using alternative body parsing middleware while awaiting patch deployment

# Update body-parser to patched version
npm update body-parser@1.20.3

# Or update via package.json dependency specification
npm install body-parser@^1.20.3 --save

# Verify installed version
npm list body-parser