CVE-2024-23873
📋 TL;DR
CVE-2024-23873 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 currencyid parameter in currencymodify.php. This affects all users running the vulnerable version of Cups Easy, particularly those with internet-facing installations. 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
Attacker steals administrator session cookies, gains full administrative access to the application, manipulates financial data, inventory records, and potentially compromises the entire system.
Likely Case
Attacker steals authenticated user sessions to perform unauthorized actions within the application, potentially modifying purchase orders, inventory data, or financial records.
If Mitigated
With proper input validation and output encoding, the attack is prevented, maintaining normal application functionality with no security impact.
🎯 Exploit Status
Exploitation requires sending a crafted URL to an authenticated user, making it suitable for phishing attacks.
🛠️ 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. Implement input validation and output encoding in currencymodify.php. 3. Sanitize the currencyid parameter before processing.
🔧 Temporary Workarounds
Input Validation Filter
allAdd server-side validation to only accept numeric values for currencyid parameter
// PHP example: if(!is_numeric($_GET['currencyid'])) { die('Invalid input'); }
Web Application Firewall Rule
allBlock requests containing script tags or JavaScript in currencyid parameter
WAF rule: SecRule ARGS:currencyid "@rx <script" "id:1001,phase:2,deny"
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to prevent script execution from untrusted sources
- Use HTTP-only and Secure flags for session cookies to make them inaccessible to JavaScript
🔍 How to Verify
Check if Vulnerable:
Test by injecting a simple XSS payload like <script>alert('test')</script> into the currencyid parameter of currencymodify.php while authenticatedCheck Version:
Check application version in admin panel or review source code for version markersVerify Fix Applied:
Attempt the same XSS injection; if the script doesn't execute and input is properly sanitized, the fix is working📡 Detection & Monitoring
Log Indicators:
- Unusual GET requests to /cupseasylive/currencymodify.php with script tags or JavaScript in parameters
- Multiple failed authentication attempts followed by successful access to currencymodify.php
Network Indicators:
- HTTP requests containing <script> tags in URL parameters
- Unusual outbound connections from web server following access to currencymodify.php
SIEM Query:
source="web_logs" AND uri="/cupseasylive/currencymodify.php" AND (param="currencyid" AND value MATCHES "<script")