CVE-2016-3142 in Mac OS X
Summary
by MITRE
The phar_parse_zipfile function in zip.c in the PHAR extension in PHP before 5.5.33 and 5.6.x before 5.6.19 allows remote attackers to obtain sensitive information from process memory or cause a denial of service (out-of-bounds read and application crash) by placing a PK\x05\x06 signature at an invalid location.
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Analysis
by VulDB Data Team • 08/19/2022
The vulnerability identified as CVE-2016-3142 resides within the PHAR extension of PHP, specifically in the phar_parse_zipfile function located in zip.c. This flaw affects PHP versions prior to 5.5.33 and 5.6.x prior to 5.6.19, representing a critical security issue that could be exploited by remote attackers to gain unauthorized access to sensitive information or disrupt service availability. The vulnerability stems from improper handling of ZIP file parsing operations when encountering malformed PK signatures at invalid memory locations.
The technical exploitation of this vulnerability occurs when PHP processes PHAR archives containing malformed ZIP files with PK signatures positioned at invalid offsets within the file structure. This improper validation leads to out-of-bounds read operations that can expose process memory contents to attackers or trigger application crashes due to memory access violations. The flaw represents a classic buffer over-read condition that can be leveraged to extract sensitive data from the application's memory space, potentially including authentication tokens, database credentials, or other confidential information. The vulnerability manifests as a memory corruption issue that can be triggered through the manipulation of PHAR archive file structures during parsing operations.
From an operational perspective, this vulnerability presents significant risks to web applications relying on PHP's PHAR extension for archive handling. Attackers can exploit this flaw to either extract sensitive information from process memory or cause denial of service conditions that disrupt application availability. The out-of-bounds read behavior creates opportunities for information disclosure attacks that align with attack patterns described in the MITRE ATT&CK framework under the information discovery and privilege escalation techniques. The vulnerability's impact extends beyond simple data exposure to include potential application stability issues that could be weaponized for more sophisticated attacks.
The security implications of CVE-2016-3142 align with CWE-125, which describes out-of-bounds read vulnerabilities, and CWE-20, which covers input validation issues. Organizations utilizing affected PHP versions face potential exposure to data leakage and service disruption attacks, particularly in environments where PHAR archives are processed from untrusted sources. The vulnerability's exploitation requires minimal privileges and can be executed remotely, making it particularly dangerous for web-facing applications. Security teams should prioritize patching affected systems and implementing proper input validation measures to prevent exploitation of this memory corruption flaw.
Mitigation strategies for this vulnerability include immediate deployment of PHP updates to versions 5.5.33 or 5.6.19 and later, which contain the necessary fixes for the PHAR extension's ZIP file parsing logic. Additionally, organizations should implement robust input validation for all PHAR archive processing operations and consider network-level restrictions on archive file handling. The implementation of proper access controls and monitoring for unusual memory access patterns can help detect potential exploitation attempts. Regular security assessments of PHP applications should include verification of PHAR extension usage and proper configuration to prevent unauthorized archive processing operations that could trigger this vulnerability.