CVE-2023-40028 Overview
Ghost is an open source content management system. Versions prior to 5.59.1 are subject to a vulnerability which allows authenticated users to upload files that are symlinks. This can be exploited to perform an arbitrary file read of any file on the host operating system. Site administrators can check for exploitation of this issue by looking for unknown symlinks within Ghost's content/ folder. Version 5.59.1 contains a fix for this issue. All users are advised to upgrade.
Critical Impact
This vulnerability allows for arbitrary file read operations by authenticated users, potentially exposing sensitive data.
Affected Products
- ghost ghost
- Not Available
- Not Available
Discovery Timeline
- Not Available - Vulnerability discovered by Not Available
- Not Available - Responsible disclosure to ghost
- Not Available - CVE CVE-2023-40028 assigned
- Not Available - ghost releases security patch
- 2023-08-15T18:15:10.547 - CVE CVE-2023-40028 published to NVD
- 2024-11-21T08:18:33.280 - Last updated in NVD database
Technical Details for CVE-2023-40028
Vulnerability Analysis
The vulnerability stems from improper handling of file uploads in Ghost. Users with authenticated access can upload symlink files that may link to sensitive files on the server. This could enable an attacker to access unauthorized data, leading to potential information disclosure.
Root Cause
The vulnerability is caused by inadequate validation of uploaded files, allowing symlinks which can be abused for arbitrary file reads.
Attack Vector
Exploitation requires network access with authentication, where the attacker uploads a malicious symlink file to the Ghost CMS instance.
# Example exploitation code (sanitized)
ln -s /etc/passwd symlink
curl -X POST -F 'file=@symlink' http://vulnerable-ghost-instance/upload
Detection Methods for CVE-2023-40028
Indicators of Compromise
- Unknown symlink files present in content/ folder
- Unusual file access logs
- Suspicious account activity
Detection Strategies
Examine file upload logs for symlinks and validate all files within the content/ directory for unauthorized symlinks. Utilize file integrity monitoring to detect changes or additions of suspicious symlinks.
Monitoring Recommendations
Continuously monitor and validate file uploads and conduct regular audits of the content/ directory. Implement logging to capture file creation and modification activities.
How to Mitigate CVE-2023-40028
Immediate Actions Required
- Upgrade to Ghost version 5.59.1 or later
- Check for existing symlinks and remove them
- Implement stringent file validation mechanisms
Patch Information
The Ghost team has provided a patch in version 5.59.1 that addresses this vulnerability by improving validation of file uploads to prevent symlink attacks.
Workarounds
No known workarounds exist aside from applying the official patch.
# Configuration example
echo "No symlinks" > .htaccess
Options +FollowSymLinks
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^ - [F]
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
