CVE-2020-7660: Serialize-javascript RCE Vulnerability

CVE-2020-7660 Overview

CVE-2020-7660 is a remote code injection vulnerability affecting serialize-javascript versions prior to 3.1.0. This Node.js library, maintained by Verizon (originally Yahoo), is widely used to serialize JavaScript objects to a superset of JSON. The vulnerability allows remote attackers to inject arbitrary code via the deleteFunctions function within index.js, potentially leading to complete system compromise in affected applications.

Critical Impact

Remote attackers can inject and execute arbitrary code on systems running vulnerable versions of serialize-javascript, potentially gaining full control of affected Node.js applications.

Affected Products

• Verizon serialize-javascript versions prior to 3.1.0
• Node.js applications utilizing vulnerable serialize-javascript package
• Web applications and build tools incorporating the affected library

Discovery Timeline

• 2020-06-01 - CVE-2020-7660 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-7660

Vulnerability Analysis

This vulnerability is classified as Insecure Deserialization (CWE-502), which occurs when untrusted data is used to abuse the logic of an application, inflict denial-of-service attacks, or execute arbitrary code. The serialize-javascript library is designed to convert JavaScript objects into serialized string representations that can be safely embedded in HTML or transmitted across networks.

The flaw exists within the deleteFunctions function in index.js, where improper handling of specially crafted input can lead to code injection. When the library processes malicious payloads, attackers can inject arbitrary JavaScript code that gets executed during the deserialization process. This is particularly dangerous in server-side rendering scenarios and build pipelines where serialized data may come from untrusted sources.

Root Cause

The root cause stems from insufficient input validation and sanitization within the deleteFunctions function. The function fails to properly escape or validate user-controlled data before processing, allowing specially crafted payloads to break out of the intended serialization context and inject executable code. This type of deserialization vulnerability is common in JavaScript libraries that handle dynamic code generation or evaluation without proper security controls.

Attack Vector

The attack is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by sending a malicious payload to an application that uses the vulnerable serialize-javascript library. The exploitation complexity is high as it requires specific conditions to be met, including the presence of the vulnerable function in the code path and the ability to control input that reaches the deserialization logic.

The attack flow typically involves:

1. Identifying an application endpoint that processes serialized data using the vulnerable library
2. Crafting a malicious payload that exploits the deleteFunctions function
3. Sending the payload to the target application
4. Achieving arbitrary code execution when the malicious data is processed

Detection Methods for CVE-2020-7660

Indicators of Compromise

• Unexpected JavaScript execution or unusual process spawning from Node.js applications
• Anomalous network connections originating from application servers
• Suspicious modifications to application files or configurations
• Unexplained CPU or memory spikes in Node.js processes
• Error logs indicating deserialization failures or unexpected code evaluation

Detection Strategies

• Audit package dependencies using npm audit or yarn audit to identify vulnerable serialize-javascript versions
• Implement static analysis tools to scan for usage patterns of the vulnerable deleteFunctions function
• Deploy runtime application self-protection (RASP) solutions to detect code injection attempts
• Monitor application logs for deserialization errors or unusual execution patterns

Monitoring Recommendations

• Enable verbose logging for applications using serialize-javascript to capture processing events
• Implement network traffic analysis to detect suspicious payloads targeting serialization endpoints
• Set up alerts for dependency vulnerability scanners in CI/CD pipelines
• Monitor for unexpected child process creation from Node.js applications

How to Mitigate CVE-2020-7660

Immediate Actions Required

• Update serialize-javascript to version 3.1.0 or later immediately
• Audit all projects and build dependencies for vulnerable serialize-javascript versions
• Review application code for direct or transitive dependencies on the affected package
• Implement input validation for any data processed by serialization functions

Patch Information

The vulnerability has been addressed in serialize-javascript version 3.1.0. The fix is available through the GitHub commit f21a6fb3ace2353413761e79717b2d210ba6ccbd. Organizations should update to the patched version through their package manager:

npm update serialize-javascript

or explicitly install the fixed version:

npm install serialize-javascript@^3.1.0

Workarounds

• If immediate patching is not possible, implement strict input validation before passing data to serialize-javascript
• Consider wrapping the library with a sanitization layer that validates input before serialization
• Restrict network access to application endpoints that process serialized data
• Implement Content Security Policy (CSP) headers to limit the impact of potential code injection

# Check current serialize-javascript version in your project
npm list serialize-javascript

# Update to the patched version
npm install serialize-javascript@latest

# Verify the update
npm list serialize-javascript