CVE-2022-2421
📋 TL;DR
CVE-2022-2421 is a critical vulnerability in the Socket.io JavaScript library that allows attackers to inject malicious function references into query objects through improper type validation in attachment parsing. This affects any application using vulnerable versions of Socket.io for real-time communication. Attackers can potentially execute arbitrary code on affected servers.
💻 Affected Systems
- Socket.io JavaScript library
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Server-side code injection leading to data manipulation, denial of service, or privilege escalation.
If Mitigated
Limited impact with proper input validation and network segmentation, potentially only causing service disruption.
🎯 Exploit Status
Exploitation requires sending specially crafted Socket.io packets. Public proof-of-concept code exists demonstrating the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Socket.io version 4.5.1 and later
Vendor Advisory: https://socket.io/blog/socket-io-4-5-1
Restart Required: Yes
Instructions:
1. Update Socket.io dependency to version 4.5.1 or later. 2. Run 'npm update socket.io' or 'yarn upgrade socket.io'. 3. Restart the Node.js application. 4. Test real-time functionality remains operational.
🔧 Temporary Workarounds
Disable Socket.io attachments
allDisable the attachments feature if not required for application functionality
Configure Socket.io server with { allowAttachments: false }
Network filtering
allImplement WAF rules to block malicious Socket.io packets
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all Socket.io message handlers
- Isolate Socket.io servers in a DMZ with strict network access controls and monitoring
🔍 How to Verify
Check if Vulnerable:
Check package.json or run 'npm list socket.io' to see if version is 4.5.0 or earlierCheck Version:
npm list socket.io | grep socket.ioVerify Fix Applied:
Verify Socket.io version is 4.5.1 or later using 'npm list socket.io'📡 Detection & Monitoring
Log Indicators:
- Unusual Socket.io attachment patterns
- Error messages related to type validation failures
- Abnormal process spawns from Node.js applications
Network Indicators:
- Malformed Socket.io packets with manipulated _placeholder objects
- Unusual WebSocket traffic patterns
SIEM Query:
source="socket.io" AND (event="attachment_parse_error" OR message="*_placeholder*" OR process="node" AND cmdline="*unusual*"