CVE-2023-31133
📋 TL;DR
This vulnerability in Ghost CMS allows attackers to brute-force filter parameters on public API endpoints to reveal private fields like passwords and emails. Self-hosted Ghost instances below version 5.46.1 are affected, while Ghost(Pro) has already been patched.
💻 Affected Systems
- Ghost CMS
📦 What is this software?
Ghost by Ghost
⚠️ Risk & Real-World Impact
Worst Case
Attackers could extract sensitive user data including passwords and email addresses, leading to credential theft, account compromise, and privacy violations.
Likely Case
Attackers discover and extract private user information through automated scanning, potentially leading to credential stuffing attacks and privacy breaches.
If Mitigated
With proper filtering validation, private fields remain protected and API endpoints function normally without data leakage.
🎯 Exploit Status
Exploitation requires brute-forcing filter parameters on public API endpoints, which is relatively straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.46.1
Vendor Advisory: https://github.com/TryGhost/Ghost/security/advisories/GHSA-r97q-ghch-82j9
Restart Required: Yes
Instructions:
1. Backup your Ghost instance. 2. Update Ghost to version 5.46.1 or later using your package manager or deployment method. 3. Restart the Ghost service. 4. Verify the update was successful.
🔧 Temporary Workarounds
Block malicious filter requests
allAdd web server rules to block requests containing 'password' or 'email' in filter parameters
# For nginx: add to server block
location ~ ^/ghost/api/content/ {
if ($args ~* "filter.*(password|email)") {
return 403;
}
}
# For Apache: add to .htaccess
RewriteEngine On
RewriteCond %{QUERY_STRING} filter.*(password|email) [NC]
RewriteRule ^ghost/api/content/ - [F]
🧯 If You Can't Patch
- Implement strict rate limiting on /ghost/api/content/* endpoints to prevent brute force attacks
- Deploy a WAF with rules to block requests containing suspicious filter parameters
🔍 How to Verify
Check if Vulnerable:
Check Ghost version via admin panel or run: ghost versionCheck Version:
ghost versionVerify Fix Applied:
Confirm version is 5.46.1 or higher and test API endpoints with filter parameters containing 'password' or 'email' return appropriate errors📡 Detection & Monitoring
Log Indicators:
- Multiple failed requests to /ghost/api/content/* with filter parameters
- Requests containing 'password' or 'email' in filter query strings
Network Indicators:
- Unusual volume of requests to API endpoints with filter parameters
- Patterns of parameter brute-forcing
SIEM Query:
source="ghost.logs" AND (url_path="/ghost/api/content/*" AND query_string="*filter*password*" OR query_string="*filter*email*")🔗 References
- https://github.com/TryGhost/Ghost/commit/b3caf16005289cc9909488391b4a26f3f4a66a90
- https://github.com/TryGhost/Ghost/releases/tag/v5.46.1
- https://github.com/TryGhost/Ghost/security/advisories/GHSA-r97q-ghch-82j9
- https://github.com/TryGhost/Ghost/commit/b3caf16005289cc9909488391b4a26f3f4a66a90
- https://github.com/TryGhost/Ghost/releases/tag/v5.46.1
- https://github.com/TryGhost/Ghost/security/advisories/GHSA-r97q-ghch-82j9
