CVE-2024-23871
📋 TL;DR
CVE-2024-23871 is a stored cross-site scripting (XSS) vulnerability in Cups Easy Purchase & Inventory version 1.0 that allows attackers to inject malicious scripts via the description parameter in unitofmeasurementmodify.php. This affects all users running the vulnerable version of Cups Easy, particularly those with internet-facing deployments. Successful exploitation could lead to session hijacking and unauthorized access to administrative functions.
💻 Affected Systems
- Cups Easy (Purchase & Inventory)
📦 What is this software?
Cups Easy by Ajaysharma
⚠️ Risk & Real-World Impact
Worst Case
Attackers steal administrator session cookies, gain full administrative access to the application, manipulate inventory data, and potentially pivot to other systems.
Likely Case
Attackers steal authenticated user session cookies to access the application with the victim's privileges, potentially modifying purchase orders or inventory data.
If Mitigated
With proper input validation and output encoding, the attack would fail, and only legitimate data would be processed.
🎯 Exploit Status
Exploitation requires the attacker to trick an authenticated user into visiting a malicious URL; no authentication bypass needed beyond initial user login.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-cups-easy
Restart Required: No
Instructions:
1. Review the INCIBE advisory for details. 2. Since no patch is available, implement workarounds or consider alternative software. 3. Monitor vendor for updates.
🔧 Temporary Workarounds
Input Validation and Output Encoding
allImplement server-side validation and HTML encoding for the description parameter in unitofmeasurementmodify.php
Modify /cupseasylive/unitofmeasurementmodify.php to add: htmlspecialchars($_POST['description'], ENT_QUOTES, 'UTF-8');
Web Application Firewall (WAF) Rules
allDeploy WAF rules to block XSS payloads in the description parameter
Add WAF rule: Block requests containing <script> tags or javascript: in description parameter
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to prevent script execution from untrusted sources
- Disable or restrict access to /cupseasylive/unitofmeasurementmodify.php if not needed
🔍 How to Verify
Check if Vulnerable:
Check if version 1.0 of Cups Easy is installed and if unitofmeasurementmodify.php exists without proper input sanitizationCheck Version:
Check application configuration files or documentation for version informationVerify Fix Applied:
Test by attempting to inject XSS payloads into the description parameter and verify they are properly encoded or blocked📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cupseasylive/unitofmeasurementmodify.php with script tags or encoded payloads
- Multiple failed login attempts followed by successful access
Network Indicators:
- HTTP requests containing malicious script payloads in description parameter
- Unexpected outbound connections from the application server
SIEM Query:
source="web_server" AND uri="/cupseasylive/unitofmeasurementmodify.php" AND (description CONTAINS "<script>" OR description CONTAINS "javascript:")