CVE-2023-3824
📋 TL;DR
This CVE describes a stack buffer overflow vulnerability in PHP's PHAR file handling that could lead to memory corruption or remote code execution. It affects PHP versions 8.0.* before 8.0.30, 8.1.* before 8.1.22, and 8.2.* before 8.2.8. Any system running vulnerable PHP versions that processes PHAR files is potentially at risk.
💻 Affected Systems
- PHP
📦 What is this software?
Fedora by Fedoraproject
Php by Php
Php by Php
Php by Php
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the PHP process, potentially leading to complete system compromise.
Likely Case
Memory corruption leading to denial of service (PHP process crash) or limited code execution depending on exploit sophistication.
If Mitigated
Denial of service from PHP process crashes if exploit attempts are blocked or fail.
🎯 Exploit Status
Exploitation requires the ability to make PHP load a malicious PHAR file, which could be achieved through file upload functionality or other means.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: PHP 8.0.30, 8.1.22, 8.2.8
Vendor Advisory: https://github.com/php/php-src/security/advisories/GHSA-jqcx-ccgc-xwhv
Restart Required: Yes
Instructions:
1. Identify PHP version with 'php -v'. 2. Update PHP using your package manager: For Ubuntu/Debian: 'sudo apt update && sudo apt upgrade php'. For RHEL/CentOS: 'sudo yum update php'. 3. Restart web server: 'sudo systemctl restart apache2' or 'sudo systemctl restart nginx'. 4. Verify update with 'php -v'.
🔧 Temporary Workarounds
Disable PHAR extension
allDisable the PHAR extension to prevent loading of PHAR files entirely.
Add 'phar.readonly = 1' to php.ini
Add 'extension=phar.so' to php.ini with a leading semicolon to comment it out
Restrict file uploads
allBlock upload or processing of .phar files in web applications.
Configure web application firewalls to block .phar files
Implement file type validation in applications
🧯 If You Can't Patch
- Implement strict file upload controls to block PHAR files
- Use web application firewalls to detect and block exploit attempts
🔍 How to Verify
Check if Vulnerable:
Run 'php -v' and check if version is in affected range: 8.0.0-8.0.29, 8.1.0-8.1.21, or 8.2.0-8.2.7.Check Version:
php -vVerify Fix Applied:
Run 'php -v' and confirm version is 8.0.30+, 8.1.22+, or 8.2.8+.📡 Detection & Monitoring
Log Indicators:
- PHP segmentation fault errors
- Unexpected process termination of PHP-FPM or Apache modules
- Failed PHAR file loading attempts
Network Indicators:
- Unusual file uploads with .phar extension
- HTTP requests attempting to trigger PHAR loading
SIEM Query:
source="*php*" AND ("segmentation fault" OR "core dumped" OR "phar" AND "load")🔗 References
- https://github.com/php/php-src/security/advisories/GHSA-jqcx-ccgc-xwhv
- https://lists.debian.org/debian-lts-announce/2023/09/msg00002.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7NBF77WN6DTVTY2RE73IGPYD6M4PIAWA/
- https://security.netapp.com/advisory/ntap-20230825-0001/
- https://github.com/php/php-src/security/advisories/GHSA-jqcx-ccgc-xwhv
- https://lists.debian.org/debian-lts-announce/2023/09/msg00002.html
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7NBF77WN6DTVTY2RE73IGPYD6M4PIAWA/
- https://security.netapp.com/advisory/ntap-20230825-0001/
