CVE-2016-1903 in Secure Backup
Summary
by MITRE
The gdImageRotateInterpolated function in ext/gd/libgd/gd_interpolation.c in PHP before 5.5.31, 5.6.x before 5.6.17, and 7.x before 7.0.2 allows remote attackers to obtain sensitive information or cause a denial of service (out-of-bounds read and application crash) via a large bgd_color argument to the imagerotate function.
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Analysis
by VulDB Data Team • 11/01/2022
The vulnerability identified as CVE-2016-1903 represents a critical security flaw in PHP's graphics handling capabilities, specifically within the gd library's image rotation functionality. This issue affects multiple PHP versions including 5.5.30 and earlier, 5.6.16 and earlier, and 7.0.1 and earlier releases. The vulnerability stems from inadequate input validation in the gdImageRotateInterpolated function which processes image rotation operations through the imagerotate function. Attackers can exploit this weakness by providing a maliciously crafted bgd_color argument that triggers improper memory handling during image processing operations.
The technical flaw manifests as an out-of-bounds read condition that occurs when the gdImageRotateInterpolated function processes large numeric values for the bgd_color parameter. This improper handling leads to memory access violations that can result in information disclosure or application crashes. The vulnerability falls under the category of CWE-125, which describes out-of-bounds read conditions in software systems. When exploited, this flaw allows remote attackers to read memory locations that should not be accessible, potentially exposing sensitive information such as stack contents, heap data, or other application memory segments that may contain credentials, session tokens, or other confidential data.
The operational impact of this vulnerability extends beyond simple denial of service conditions to include potential information disclosure risks that could compromise system security. Remote attackers can leverage this vulnerability to cause application crashes, leading to service disruption, or to extract sensitive information from memory locations, which could be used to further compromise the affected systems. The vulnerability affects web applications that utilize PHP's image manipulation capabilities, particularly those that process user-uploaded images or allow dynamic image generation. This makes it particularly dangerous in web environments where user input is processed without proper sanitization, as attackers can craft malicious image parameters that trigger the vulnerability during normal operation.
The exploitation of this vulnerability aligns with ATT&CK technique T1059, which involves executing malicious code through command injection or manipulation of application logic. Organizations using affected PHP versions should immediately implement mitigations including updating to patched versions of PHP, implementing input validation for image processing functions, and deploying web application firewalls to detect and block suspicious image parameter values. The recommended remediation involves upgrading to PHP 5.5.31, 5.6.17, or 7.0.2 and later versions where the vulnerability has been addressed through proper bounds checking and memory validation in the gd library implementation. Additionally, administrators should review application code to ensure that user-supplied image parameters are properly sanitized and validated before being passed to image processing functions, and implement monitoring to detect unusual patterns of image processing requests that may indicate exploitation attempts.