CVE-2021-47908
📋 TL;DR
Ultimate POS 4.4 contains a persistent cross-site scripting vulnerability in the product name parameter that allows attackers to inject malicious scripts. When exploited, this can lead to session hijacking, credential theft, or redirection to malicious sites. All users running Ultimate POS 4.4 with product management functionality are affected.
💻 Affected Systems
- Ultimate POS
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of admin accounts leading to data theft, financial fraud, or complete system takeover through privilege escalation.
Likely Case
Session hijacking of regular users leading to unauthorized transactions, data manipulation, or credential theft.
If Mitigated
Limited impact with proper input validation and output encoding, potentially only affecting non-critical functionality.
🎯 Exploit Status
Exploitation requires access to product add/edit functions, which typically require authentication. XSS payloads are well-documented and easy to craft.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.5 or later
Vendor Advisory: https://ultimatefosters.com/docs/ultimatepos/
Restart Required: No
Instructions:
1. Backup your database and application files. 2. Download latest version from official source. 3. Replace existing installation files. 4. Run any database migration scripts if provided. 5. Test functionality.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation to sanitize product name field
Implement regex filter: /^[a-zA-Z0-9\s\-\_\,\.]+$/ for product names
Output Encoding
allApply HTML entity encoding to all user-controlled output in product display
Use htmlspecialchars() or equivalent function when displaying product names
🧯 If You Can't Patch
- Disable product management functionality for non-admin users
- Implement web application firewall (WAF) rules to block XSS payloads in product name parameter
🔍 How to Verify
Check if Vulnerable:
Test by entering <script>alert('XSS')</script> in product name field and checking if script executes when product is viewed.Check Version:
Check application version in admin panel or read version.txt file in installation directory.Verify Fix Applied:
Attempt same XSS test after patch - script should be displayed as plain text, not executed.📡 Detection & Monitoring
Log Indicators:
- Unusual product names containing script tags or JavaScript code
- Multiple failed product creation attempts with special characters
Network Indicators:
- HTTP requests with script tags in POST parameters
- Unusual outbound connections from application server
SIEM Query:
source="web_server" AND (product_name="*<script>*" OR product_name="*javascript:*")