CVE-2021-23592
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code through insecure deserialization in the topthink/framework PHP package. It affects all applications using versions before 6.0.12 of this framework. Attackers can exploit this to gain control over affected systems.
💻 Affected Systems
- topthink/framework
📦 What is this software?
Thinkphp by Thinkphp
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Remote code execution allowing attackers to install malware, steal sensitive data, or use the system as a foothold for further attacks.
If Mitigated
Limited impact if proper input validation and network segmentation are in place, though deserialization vulnerabilities remain dangerous.
🎯 Exploit Status
Deserialization vulnerabilities are commonly exploited and weaponized; proof-of-concept code is available in public repositories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.0.12
Vendor Advisory: https://github.com/top-think/framework/releases/tag/v6.0.12
Restart Required: Yes
Instructions:
1. Update composer.json to require "topthink/framework": "^6.0.12"
2. Run composer update topthink/framework
3. Restart your PHP application/web server
🔧 Temporary Workarounds
Input Validation Filter
allImplement strict input validation to reject any untrusted serialized data before it reaches the Driver class.
Disable Vulnerable Features
allIf possible, disable or restrict usage of the affected Driver class methods that perform deserialization.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected systems from critical assets
- Deploy web application firewall (WAF) rules to block serialized data patterns
🔍 How to Verify
Check if Vulnerable:
Check composer.json or composer.lock for topthink/framework version; if version is <6.0.12, the system is vulnerable.Check Version:
composer show topthink/framework | grep versionsVerify Fix Applied:
After updating, verify that composer.lock shows topthink/framework version 6.0.12 or higher.📡 Detection & Monitoring
Log Indicators:
- Unusual PHP errors related to unserialize()
- Suspicious POST/PUT requests containing serialized data patterns
- Unexpected process execution from web server context
Network Indicators:
- HTTP requests containing serialized PHP object patterns (O:数字, s:数字)
- Outbound connections from web servers to unknown external IPs
SIEM Query:
source="web_logs" AND ("unserialize" OR "O:\d+" OR "s:\d+")🔗 References
- https://github.com/top-think/framework/commit/d3b5aeae94bc71bae97977d05cd12c3e0550905c
- https://github.com/top-think/framework/releases/tag/v6.0.12
- https://snyk.io/vuln/SNYK-PHP-TOPTHINKFRAMEWORK-2385695
- https://github.com/top-think/framework/commit/d3b5aeae94bc71bae97977d05cd12c3e0550905c
- https://github.com/top-think/framework/releases/tag/v6.0.12
- https://snyk.io/vuln/SNYK-PHP-TOPTHINKFRAMEWORK-2385695
