CVE-2005-0525 in PHP
Summary
by MITRE
The php_next_marker function in image.c for PHP 4.2.2, 4.3.9, 4.3.10 and 5.0.3, as reachable by the getimagesize PHP function, allows remote attackers to cause a denial of service (infinite loop) via a JPEG image with an invalid marker value, which causes a negative length value to be passed to php_stream_seek.
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Analysis
by VulDB Data Team • 07/01/2021
The vulnerability described in CVE-2005-0525 represents a critical denial of service flaw affecting PHP versions 4.2.2, 4.3.9, 4.3.10, and 5.0.3. This issue manifests within the php_next_marker function located in the image.c file, which is invoked by the getimagesize PHP function. The vulnerability arises from insufficient input validation when processing JPEG image files, creating a scenario where malformed image data can trigger unexpected behavior in the PHP runtime environment. The flaw specifically targets the handling of JPEG markers, which are essential components used to define the structure and metadata of jpeg images.
The technical implementation of this vulnerability stems from how PHP processes JPEG image markers during image size detection operations. When the getimagesize function encounters a JPEG image containing an invalid marker value, the php_next_marker function fails to properly validate the marker data. This validation failure results in a negative length value being calculated and subsequently passed to the php_stream_seek function. The php_stream_seek function, designed to move the file pointer within a stream, becomes unable to handle negative values properly, leading to an infinite loop condition. This infinite loop consumes excessive system resources and effectively renders the affected PHP application unavailable to legitimate users.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited remotely by attackers without requiring authentication or special privileges. The denial of service condition affects any PHP application that utilizes the getimagesize function to process user-uploaded or externally sourced JPEG images. This includes web applications such as content management systems, image galleries, file upload handlers, and any other platforms that rely on PHP's image processing capabilities. The vulnerability can be particularly dangerous in high-traffic environments where a single malicious JPEG file can cause cascading failures across multiple application processes. The infinite loop behavior can exhaust system memory and CPU resources, potentially affecting not only the specific PHP process but also the entire server infrastructure.
This vulnerability aligns with CWE-129, which addresses improper validation of input ranges, and demonstrates characteristics consistent with CWE-134, concerning the use of format strings in ways that can lead to code execution or resource exhaustion. From an attack framework perspective, this issue maps to ATT&CK technique T1499.004, focusing on network denial of service attacks through resource exhaustion. The vulnerability also reflects broader concerns about input sanitization in image processing libraries, where malformed data can cause applications to behave unpredictably. Organizations affected by this vulnerability should implement immediate mitigations including updating to patched PHP versions, implementing input validation for image uploads, and deploying web application firewalls to filter potentially malicious image files. The fix typically involves adding proper validation checks within the php_next_marker function to prevent negative length values from being passed to php_stream_seek, thereby eliminating the infinite loop condition.