CVE-2017-12934 : Exploit Details and Defense Strategies

CVE-2017-12934, published on August 18, 2017, addresses a heap use after free vulnerability in PHP versions 7.0.x and 7.1.x. The vulnerability could be exploited during the unserialization process, potentially impacting PHP's integrity.

Understanding CVE-2017-12934

This CVE entry highlights a critical security issue in PHP versions 7.0.x and 7.1.x.

What is CVE-2017-12934?

The vulnerability in PHP versions 7.0.x before 7.0.21 and 7.1.x before 7.1.7 involves a heap use after free vulnerability during the processing of untrusted data in the unserialization process. The vulnerability is specifically related to the zval_get_type function in Zend/zend_types.h.

The Impact of CVE-2017-12934

If successfully exploited, this vulnerability could have unpredictable impacts on the integrity of PHP, potentially leading to security breaches and system compromise.

Technical Details of CVE-2017-12934

This section delves into the technical aspects of the CVE.

Vulnerability Description

The vulnerability lies in the ext/standard/var_unserializer.re file in PHP versions 7.0.x before 7.0.21 and 7.1.x before 7.1.7. It is prone to a heap use after free vulnerability while unserializing untrusted data, specifically related to the zval_get_type function in Zend/zend_types.h.

Affected Systems and Versions

PHP versions 7.0.x before 7.0.21
PHP versions 7.1.x before 7.1.7

Exploitation Mechanism

Exploitation of this vulnerability can result in an unspecified impact on the integrity of PHP, potentially leading to system compromise.

Mitigation and Prevention

Protecting systems from CVE-2017-12934 is crucial for maintaining security.

Immediate Steps to Take

Update PHP to versions 7.0.21 or 7.1.7 to patch the vulnerability.
Monitor for any unusual PHP behavior that could indicate exploitation.

Long-Term Security Practices

Implement secure coding practices to prevent similar vulnerabilities.
Regularly update and patch PHP and other software components to address security flaws.

Patching and Updates

Ensure timely installation of security patches and updates for PHP to mitigate the risk of exploitation.