CVE-2023-30321
📋 TL;DR
This CVE describes a Cross-Site Scripting (XSS) vulnerability in the textMessage field of the LoginServlet.java file in wliang6 ChatEngine. Attackers can inject malicious scripts that execute in users' browsers when they interact with the vulnerable login functionality. Any system running the affected ChatEngine commit is vulnerable.
💻 Affected Systems
- wliang6 ChatEngine
📦 What is this software?
Chatengine by Chatengine Project
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, perform account takeovers, redirect users to malicious sites, or execute arbitrary JavaScript in victims' browsers leading to complete compromise of user accounts.
Likely Case
Attackers would typically steal authentication cookies or session tokens to hijack user accounts, potentially leading to unauthorized access to chat functionality and user data.
If Mitigated
With proper input validation and output encoding, the vulnerability would be neutralized, preventing script execution while maintaining normal login functionality.
🎯 Exploit Status
XSS vulnerabilities are commonly exploited and public advisories exist with technical details.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified
Vendor Advisory: https://payatu.com/advisory/cross-site-scripting-xss-vulnerability-in-loginservlet-java-wliang6-chatengine-allows-attackers-to-execute-arbitrary-code/
Restart Required: Yes
Instructions:
1. Review the vulnerable code at lines 55-64 in LoginServlet.java
2. Implement proper input validation and output encoding
3. Recompile and redeploy the application
4. Restart the application server
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allDeploy WAF rules to block XSS payloads targeting the textMessage parameter
Input Validation Filter
allImplement a servlet filter to sanitize all textMessage parameter inputs
🧯 If You Can't Patch
- Isolate the vulnerable system from internet access
- Implement strict Content Security Policy (CSP) headers
🔍 How to Verify
Check if Vulnerable:
Test by submitting a basic XSS payload like <script>alert('XSS')</script> in the textMessage field during login and check if it executesCheck Version:
Check git commit hash: git log --oneline -1Verify Fix Applied:
After patching, test with the same XSS payloads and verify they are properly sanitized or blocked📡 Detection & Monitoring
Log Indicators:
- Unusual script tags or JavaScript in login requests
- Multiple failed login attempts with script-like content
Network Indicators:
- HTTP requests containing script tags in textMessage parameter
- Unusual Content-Type headers in login requests
SIEM Query:
source="*access.log*" AND "textMessage" AND ("<script" OR "javascript:" OR "onerror=" OR "onload=")🔗 References
- https://github.com/wliang6/ChatEngine/blob/fded8e710ad59f816867ad47d7fc4862f6502f3e/src/chatbotapp/LoginServlet.java#L55:L64
- https://payatu.com/advisory/cross-site-scripting-xss-vulnerability-in-loginservlet-java-wliang6-chatengine-allows-attackers-to-execute-arbitrary-code/
- https://github.com/wliang6/ChatEngine/blob/fded8e710ad59f816867ad47d7fc4862f6502f3e/src/chatbotapp/LoginServlet.java#L55:L64
- https://payatu.com/advisory/cross-site-scripting-xss-vulnerability-in-loginservlet-java-wliang6-chatengine-allows-attackers-to-execute-arbitrary-code/
