CVE-2023-48826
📋 TL;DR
Time Slots Booking Calendar 4.0 contains a CSV injection vulnerability in the unique ID field of the Reservations List. This allows attackers to inject malicious formulas into exported CSV files, potentially leading to code execution when opened in spreadsheet applications. Organizations using this specific version of the booking calendar software are affected.
💻 Affected Systems
- Time Slots Booking Calendar
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could execute arbitrary code on victim systems when users open malicious CSV exports in vulnerable spreadsheet applications, potentially leading to full system compromise.
Likely Case
Attackers could manipulate CSV exports to execute formulas that steal data, corrupt files, or perform unauthorized actions when opened in spreadsheet software.
If Mitigated
With proper input validation and sanitization, the vulnerability would be prevented from being exploited.
🎯 Exploit Status
Exploitation requires access to the Reservations List functionality, but the injection technique itself is straightforward once access is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor for latest version
Vendor Advisory: https://www.phpjabbers.com/time-slots-booking-calendar/
Restart Required: No
Instructions:
1. Check the vendor website for security updates
2. Update to the latest patched version
3. Verify the unique ID field now properly sanitizes CSV output
🔧 Temporary Workarounds
Input Sanitization
allImplement server-side validation to sanitize unique ID field inputs before CSV export
Implement input validation to strip or escape special characters (=, +, -, @) from unique ID field
CSV Export Restriction
allTemporarily disable CSV export functionality for reservations
Disable CSV export feature in application configuration
🧯 If You Can't Patch
- Implement web application firewall rules to detect and block CSV injection attempts
- Educate users to never open CSV files from untrusted sources in spreadsheet applications
🔍 How to Verify
Check if Vulnerable:
Test if unique ID field accepts special characters like =, +, -, @ that could trigger formula execution in CSV exportsCheck Version:
Check application version in admin panel or configuration filesVerify Fix Applied:
Verify that CSV exports no longer contain raw special characters that could be interpreted as formulas📡 Detection & Monitoring
Log Indicators:
- Unusual CSV export requests
- Special characters in unique ID field submissions
Network Indicators:
- CSV file downloads containing formula characters
SIEM Query:
Search for CSV export requests containing special characters like =, +, -, @ in query parameters