CVE-2023-48833
📋 TL;DR
This vulnerability in Time Slots Booking Calendar 4.0 allows attackers to send unlimited AJAX requests to the pjActionAJaxSend endpoint, causing resource exhaustion through denial of service. Any website running this vulnerable plugin version is affected, potentially making the service unavailable to legitimate users.
💻 Affected Systems
- Time Slots Booking Calendar
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to resource exhaustion, affecting all users of the booking system and potentially impacting the entire website if shared resources are exhausted.
Likely Case
Intermittent service degradation or temporary unavailability of the booking calendar functionality during attack periods.
If Mitigated
Minimal impact with proper rate limiting and resource monitoring in place.
🎯 Exploit Status
Exploitation requires no authentication and can be performed with simple HTTP requests. Public exploit details are available in the Packet Storm references.
🛠️ 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. Log into WordPress admin panel
2. Navigate to Plugins > Installed Plugins
3. Find Time Slots Booking Calendar
4. Click 'Update Now' if update available
5. Alternatively, download latest version from vendor site and manually update
🔧 Temporary Workarounds
Web Application Firewall Rate Limiting
allImplement rate limiting at the WAF or reverse proxy level to restrict requests to the vulnerable endpoint.
# Example nginx rate limiting
limit_req_zone $binary_remote_addr zone=bookinglimit:10m rate=10r/s;
location ~* pjActionAJaxSend { limit_req zone=bookinglimit; }
IP-based Blocking
linuxTemporarily block suspicious IPs making excessive requests to the vulnerable endpoint.
# iptables example
iptables -A INPUT -p tcp --dport 80 -m string --string "pjActionAJaxSend" --algo bm -m recent --set --name bookingattack
iptables -A INPUT -p tcp --dport 80 -m string --string "pjActionAJaxSend" --algo bm -m recent --update --seconds 60 --hitcount 20 --name bookingattack -j DROP
🧯 If You Can't Patch
- Implement strict rate limiting at the web server or application firewall level
- Monitor server resources and set up alerts for abnormal request patterns to the vulnerable endpoint
🔍 How to Verify
Check if Vulnerable:
Check WordPress plugin version in admin panel or examine plugin files for version 4.0 in wp-content/plugins/time-slots-booking-calendar/Check Version:
grep -r "Version:" wp-content/plugins/time-slots-booking-calendar/*.phpVerify Fix Applied:
Verify plugin version is updated beyond 4.0 and test that rate limiting is functioning on the pjActionAJaxSend endpoint📡 Detection & Monitoring
Log Indicators:
- High frequency of requests to URLs containing 'pjActionAJaxSend'
- Increased error rates or timeout errors in application logs
- Abnormal resource usage spikes coinciding with request patterns
Network Indicators:
- Unusually high volume of HTTP POST requests to booking calendar endpoints
- Requests from single IPs at rates exceeding normal user behavior
SIEM Query:
source="web_logs" AND url="*pjActionAJaxSend*" | stats count by src_ip | where count > 100