CVE-2021-3815
📋 TL;DR
CVE-2021-3815 is a prototype pollution vulnerability in utils.js that allows attackers to modify object prototypes, potentially leading to denial of service, remote code execution, or privilege escalation. This affects applications using vulnerable versions of the utils.js library. Developers and organizations using this library in their Node.js applications are at risk.
💻 Affected Systems
- utils.js
📦 What is this software?
Utils.js by Utils.js Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Denial of service, application crashes, or limited privilege escalation within the application context.
If Mitigated
Limited impact with proper input validation and security controls, potentially only causing application instability.
🎯 Exploit Status
Proof-of-concept exploits are publicly available, making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.3.6 and later
Vendor Advisory: https://github.com/fabiocaccamo/utils.js/commit/102efafb291ce1916985514440d3bf8a6826890a
Restart Required: Yes
Instructions:
1. Update package.json to use utils.js version 0.3.6 or higher. 2. Run 'npm update utils.js' or 'yarn upgrade utils.js'. 3. Restart your application. 4. Test functionality to ensure compatibility.
🔧 Temporary Workarounds
Input validation wrapper
allImplement custom input validation for all object manipulation functions to reject suspicious properties.
Object.freeze on prototypes
allFreeze critical object prototypes to prevent modification.
Object.freeze(Object.prototype);
Object.freeze(Array.prototype);
🧯 If You Can't Patch
- Implement strict Content Security Policy and input validation at application layer
- Isolate vulnerable components in sandboxed environments or containers
🔍 How to Verify
Check if Vulnerable:
Check package.json or package-lock.json for utils.js version. If version is below 0.3.6, you are vulnerable.Check Version:
npm list utils.js | grep utils.jsVerify Fix Applied:
After updating, verify the version is 0.3.6 or higher using 'npm list utils.js' or check package.json.📡 Detection & Monitoring
Log Indicators:
- Unusual object property modifications
- Application crashes with prototype-related errors
- Unexpected __proto__ or constructor property assignments
Network Indicators:
- HTTP requests with specially crafted JSON payloads containing __proto__ properties
SIEM Query:
source="application.logs" AND ("__proto__" OR "prototype pollution" OR "utils.js")🔗 References
- https://github.com/fabiocaccamo/utils.js/commit/102efafb291ce1916985514440d3bf8a6826890a
- https://huntr.dev/bounties/20f48c63-f078-4173-bcac-a9f34885f2c0
- https://github.com/fabiocaccamo/utils.js/commit/102efafb291ce1916985514440d3bf8a6826890a
- https://huntr.dev/bounties/20f48c63-f078-4173-bcac-a9f34885f2c0
