CVE-2004-1064 in PHP
Summary
by MITRE
The safe mode checks in PHP 4.x to 4.3.9 and PHP 5.x to 5.0.2 truncate the file path before passing the data to the realpath function, which could allow attackers to bypass safe mode. NOTE: this issue was originally REJECTed by its CNA before publication, but that decision is in active dispute. This candidate may change significantly in the future as a result of further discussion.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability described in CVE-2004-1064 represents a critical security flaw in PHP's safe mode implementation that existed across multiple versions of the PHP runtime environment. This issue specifically affects PHP versions 4.x through 4.3.9 and 5.x through 5.0.2, where the safe mode protection mechanisms were fundamentally compromised due to improper handling of file paths during validation processes. The vulnerability stems from a design flaw in how PHP processes file paths before invoking the realpath function, creating a potential bypass mechanism that undermines the intended security boundaries of the safe mode feature.
The technical root cause of this vulnerability lies in the truncation of file paths during the safe mode validation process. When PHP processes file operations under safe mode restrictions, it should validate that requested file paths fall within designated safe directories. However, the implementation in affected versions truncates these paths before passing them to the realpath function, which is responsible for resolving absolute paths and normalizing file references. This truncation process creates a scenario where attackers can manipulate file paths to bypass the intended restrictions, as the truncated paths may not accurately represent the actual file locations being accessed. The vulnerability essentially allows attackers to craft file paths that appear legitimate to the truncated validation but contain malicious elements that can be exploited to access restricted files or directories.
The operational impact of CVE-2004-1064 is significant and potentially devastating for web applications running vulnerable PHP versions. Attackers exploiting this vulnerability can bypass safe mode restrictions to access files that should be protected, potentially leading to unauthorized data access, privilege escalation, and complete system compromise. This vulnerability directly violates the principle of least privilege that safe mode is designed to enforce, allowing malicious users to circumvent file access controls that are fundamental to web application security. The impact extends beyond simple file access, as successful exploitation could enable attackers to read sensitive configuration files, database credentials, or other critical system information that should remain protected.
From a cybersecurity perspective, this vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and represents a classic case of path traversal manipulation that can be categorized under ATT&CK technique T1059.101 (Command and Scripting Interpreter: Visual Basic). The flaw demonstrates how improper input validation and path handling can create security bypass mechanisms that undermine fundamental security controls. Organizations running vulnerable PHP installations face substantial risk of data breaches, as attackers can exploit this vulnerability to access restricted files without proper authentication or authorization. The vulnerability also highlights the importance of proper path resolution and validation in web applications, as the truncation process creates an attack surface that can be systematically exploited.
The mitigation strategy for CVE-2004-1064 requires immediate action from affected organizations, including upgrading to patched versions of PHP where the vulnerability has been addressed. System administrators should prioritize updating their PHP installations to versions that properly handle file paths before invoking realpath functions, ensuring that path truncation no longer occurs during safe mode validation. Additionally, organizations should implement comprehensive monitoring for suspicious file access patterns and consider additional security measures such as web application firewalls that can detect and block malicious path manipulation attempts. The vulnerability also underscores the importance of regular security assessments and the need for organizations to maintain current knowledge of security patches and updates for their web application frameworks.