CVE-2020-7062 : Vulnerability Insights and Analysis
Learn about CVE-2020-7062, a vulnerability in PHP versions 7.2.x, 7.3.x, and 7.4.x that can lead to a null pointer dereference during file uploads. Find out the impact, affected systems, and mitigation steps.
In PHP versions 7.2.x below 7.2.28, 7.3.x below 7.3.15, and 7.4.x below 7.4.3, a vulnerability exists in the file upload functionality that can lead to a null pointer dereference, potentially causing a crash.
Understanding CVE-2020-7062
What is CVE-2020-7062?
This CVE refers to a flaw in PHP versions that can trigger a null pointer dereference when certain conditions are met during file upload operations.
The Impact of CVE-2020-7062
The vulnerability can result in a crash due to a null pointer dereference, potentially impacting the availability of the PHP application.
Technical Details of CVE-2020-7062
Vulnerability Description
When using file upload functionality in affected PHP versions, if upload progress tracking is enabled but session.upload_progress.cleanup is disabled, a null pointer dereference may occur, leading to a crash.
Affected Systems and Versions
- PHP 7.2.x versions below 7.2.28
- PHP 7.3.x versions below 7.3.15
- PHP 7.4.x versions below 7.4.3
Exploitation Mechanism
The vulnerability arises when the upload progress tracking is enabled, but the cleanup process is disabled, causing the upload procedure to attempt to clean up non-existent data, resulting in a null pointer dereference.
Mitigation and Prevention
Immediate Steps to Take
- Disable file uploading if not essential
- Turn off file upload tracking
- Enable session.upload_progress.cleanup to mitigate the risk
Long-Term Security Practices
- Regularly update PHP to the latest secure version
- Implement secure coding practices to prevent similar vulnerabilities
Patching and Updates
Apply the necessary security updates provided by PHP to address this vulnerability.