CVE-2021-25912
📋 TL;DR
This is a prototype pollution vulnerability in the 'dotty' JavaScript library that allows attackers to modify object prototypes, potentially leading to denial of service or remote code execution. Any application using vulnerable versions of dotty is affected, particularly Node.js applications that process untrusted user input.
💻 Affected Systems
- dotty
📦 What is this software?
Dotty by Dotty 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 through application crashes or instability, with potential for limited remote code execution in specific configurations.
If Mitigated
Limited impact if input validation and sanitization are implemented, though prototype pollution can bypass some controls.
🎯 Exploit Status
Prototype pollution exploits are well-documented and can be automated. The high CVSS score suggests weaponization is probable.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.1.1 and later
Vendor Advisory: https://github.com/deoxxa/dotty/commit/cd997d37917186c131be71501a698803f2b7ebdb
Restart Required: Yes
Instructions:
1. Update dotty dependency to version 0.1.1 or later. 2. Update package.json: 'dotty': '^0.1.1'. 3. Run 'npm update dotty' or 'yarn upgrade dotty'. 4. Restart the application.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict input validation to reject malformed objects that could trigger prototype pollution.
Object.freeze on prototypes
allFreeze Object.prototype to prevent prototype pollution attacks.
Object.freeze(Object.prototype);
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all user-controlled data
- Use alternative libraries like lodash.get or implement custom safe property access functions
🔍 How to Verify
Check if Vulnerable:
Check package.json or package-lock.json for dotty version. If version is between 0.0.1 and 0.1.0 inclusive, the system is vulnerable.Check Version:
npm list dotty | grep dottyVerify Fix Applied:
Verify dotty version is 0.1.1 or later in package.json and test application functionality with known safe inputs.📡 Detection & Monitoring
Log Indicators:
- Unexpected application crashes
- Unusual memory usage patterns
- Errors related to object property access
Network Indicators:
- Unusual HTTP requests with nested object structures
- Requests containing __proto__ or constructor properties
SIEM Query:
source="application.logs" AND ("prototype pollution" OR "dotty" OR "CVE-2021-25912")🔗 References
- https://github.com/deoxxa/dotty/commit/cd997d37917186c131be71501a698803f2b7ebdb
- https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25912
- https://github.com/deoxxa/dotty/commit/cd997d37917186c131be71501a698803f2b7ebdb
- https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25912
