CVE-2023-1938
📋 TL;DR
This vulnerability in WP Fastest Cache WordPress plugin allows attackers to perform Blind Server-Side Request Forgery (SSRF) attacks. Attackers can trick authenticated administrators into making unintended requests to internal systems. WordPress sites using vulnerable versions of this plugin are affected.
💻 Affected Systems
- WP Fastest Cache WordPress Plugin
📦 What is this software?
Wp Fastest Cache by Wpfastestcache
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access internal services, perform port scanning, interact with cloud metadata services, or pivot to internal network exploitation.
Likely Case
Attackers would use CSRF to make authenticated administrators perform SSRF requests, potentially accessing internal web services or APIs.
If Mitigated
With proper network segmentation and egress filtering, impact would be limited to information disclosure about internal services.
🎯 Exploit Status
Exploitation requires CSRF against authenticated admin users. SSRF payloads can be delivered via malicious links or sites.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.1.5 and later
Vendor Advisory: https://wpscan.com/vulnerability/92b1c6d8-51db-46aa-bde6-abdfb091aab5
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find WP Fastest Cache. 4. Click 'Update Now' if available. 5. Alternatively, download version 1.1.5+ from WordPress repository and replace plugin files.
🔧 Temporary Workarounds
Disable WP Fastest Cache Plugin
allTemporarily disable the vulnerable plugin until patching is possible
wp plugin deactivate wp-fastest-cache
Restrict Admin Access
allLimit administrator accounts and implement strong authentication controls
🧯 If You Can't Patch
- Implement network egress filtering to restrict outbound HTTP requests from web servers
- Deploy Web Application Firewall (WAF) with CSRF protection and SSRF detection rules
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin panel → Plugins → WP Fastest Cache → Version. If version is below 1.1.5, system is vulnerable.Check Version:
wp plugin get wp-fastest-cache --field=versionVerify Fix Applied:
Verify WP Fastest Cache plugin version is 1.1.5 or higher in WordPress admin panel.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound HTTP requests from web server to internal IPs
- Multiple failed authentication attempts on admin pages
Network Indicators:
- HTTP requests from web server to internal services (192.168.*, 10.*, 172.16-31.*)
- Requests to cloud metadata endpoints (169.254.169.254)
SIEM Query:
source="web_server_logs" AND (dest_ip IN (192.168.0.0/16, 10.0.0.0/8, 172.16.0.0/12) OR dest_ip=169.254.169.254) AND uri CONTAINS "wp-admin/admin-ajax.php" AND params CONTAINS "wpfc"