CVE-2019-9675 : What You Need to Know

A vulnerability was found in PHP versions 7.x prior to 7.1.27 and 7.3.x prior to 7.3.3, specifically in the phar_tar_writeheaders_int function in the ext/phar/tar.c file. This vulnerability is related to a buffer overflow due to a lengthy link value. Although the vendor states that this link value is only used when an archive contains a symlink, which is currently not possible, it still poses a theoretical security risk.

Understanding CVE-2019-9675

This CVE entry highlights a buffer overflow vulnerability in PHP versions 7.x before 7.1.27 and 7.3.x before 7.3.3.

What is CVE-2019-9675?

The vulnerability in the phar_tar_writeheaders_int function in the ext/phar/tar.c file of PHP versions 7.x before 7.1.27 and 7.3.x before 7.3.3 allows for a buffer overflow due to an excessively long link value. Although the practical exploitation of this issue is unlikely, it could potentially compromise security.

The Impact of CVE-2019-9675

While the vulnerability theoretically compromises security, the actual likelihood of an attack is typically low due to the specific conditions required for exploitation.

Technical Details of CVE-2019-9675

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability arises from a buffer overflow in the phar_tar_writeheaders_int function caused by an extended link value.

Affected Systems and Versions

PHP versions 7.x before 7.1.27
PHP versions 7.3.x before 7.3.3

Exploitation Mechanism

The vulnerability can be exploited through a lengthy link value, potentially leading to a buffer overflow.

Mitigation and Prevention

Protecting systems from CVE-2019-9675 involves immediate actions and long-term security practices.

Immediate Steps to Take

Update PHP to versions 7.1.27 or 7.3.3 to mitigate the vulnerability.
Monitor vendor advisories for any patches or security updates.

Long-Term Security Practices

Regularly update PHP and other software to the latest versions to address known vulnerabilities.
Implement secure coding practices to minimize the risk of buffer overflows and other security issues.

Patching and Updates

Apply patches provided by PHP to fix the buffer overflow vulnerability.