CVE-2018-20783 : Security Advisory and Response

PHP versions prior to 5.6.39, 7.x before 7.0.33, 7.1.x before 7.1.25, and 7.2.x before 7.2.13 are vulnerable to a PHAR reading functions issue that could allow unauthorized memory access.

Understanding CVE-2018-20783

This CVE identifies a vulnerability in PHP versions that could be exploited by attackers to access memory beyond the actual data while parsing a .phar file.

What is CVE-2018-20783?

The vulnerability in the phar_parse_pharfile function in ext/phar/phar.c allows attackers to read both allocated and unallocated memory, potentially leading to unauthorized access.

The Impact of CVE-2018-20783

The vulnerability could be exploited by malicious actors to access sensitive information or execute arbitrary code on affected systems, posing a significant security risk.

Technical Details of CVE-2018-20783

PHP versions prior to 5.6.39, 7.x before 7.0.33, 7.1.x before 7.1.25, and 7.2.x before 7.2.13 are susceptible to this vulnerability.

Vulnerability Description

A buffer over-read in PHAR reading functions may allow attackers to read memory past the actual data when attempting to parse a .phar file, specifically related to phar_parse_pharfile in ext/phar/phar.c.

Affected Systems and Versions

PHP versions prior to 5.6.39
PHP 7.x before 7.0.33
PHP 7.1.x before 7.1.25
PHP 7.2.x before 7.2.13

Exploitation Mechanism

Attackers can exploit this vulnerability by manipulating a .phar file to gain unauthorized access to memory, potentially leading to data theft or code execution.

Mitigation and Prevention

Immediate Steps to Take:

Update PHP to versions 5.6.39, 7.0.33, 7.1.25, or 7.2.13 to patch the vulnerability.
Monitor for any unusual activities on the system that could indicate exploitation. Long-Term Security Practices:
Regularly update PHP and other software to mitigate potential vulnerabilities.
Implement strong access controls and network security measures to prevent unauthorized access.
Educate users on safe browsing habits and the importance of software updates.
Consider implementing intrusion detection systems to detect and respond to potential attacks.
Stay informed about security advisories and patches released by PHP and other relevant vendors.

Patching and Updates

Ensure that PHP is regularly updated to the latest secure versions to protect against known vulnerabilities and security threats.