CVE-2018-3837 in Simple DirectMedia Layer
Summary
by MITRE
An exploitable information disclosure vulnerability exists in the PCX image rendering functionality of Simple DirectMedia Layer SDL2_image-2.0.2. A specially crafted PCX image can cause an out-of-bounds read on the heap, resulting in information disclosure . An attacker can display a specially crafted image to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/27/2023
The vulnerability identified as CVE-2018-3837 represents a critical information disclosure flaw within the Simple DirectMedia Layer SDL2_image library version 2.0.2. This vulnerability specifically affects the PCX image rendering functionality, which is part of a widely-used multimedia library that provides cross-platform support for graphics and audio operations in various software applications. The flaw stems from inadequate bounds checking during the processing of PCX image files, creating a scenario where maliciously crafted image data can trigger unexpected behavior in the underlying memory management system.
The technical exploitation of this vulnerability occurs through an out-of-bounds heap read condition that arises when the SDL2_image library attempts to parse specially crafted PCX image files. When processing these malformed images, the library fails to properly validate the dimensions and data structure of the PCX file, leading to memory access violations that can result in information disclosure. The heap-based nature of this vulnerability means that the attacker can potentially read sensitive data from adjacent memory locations, including stack contents, heap metadata, or other application data that may be stored in memory proximity to the affected buffer.
This vulnerability has significant operational impact across numerous software applications that rely on SDL2_image for image processing capabilities. The information disclosure aspect poses serious security risks as attackers can potentially extract sensitive data such as cryptographic keys, user credentials, application state information, or other confidential data stored in memory. The vulnerability's exploitability is relatively straightforward since it only requires displaying a specially crafted PCX image to trigger the condition, making it particularly dangerous in scenarios where users might encounter untrusted image files. The flaw affects not just desktop applications but also mobile and embedded systems that utilize SDL2_image for multimedia processing.
The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter usage, though in this case the exploitation occurs through file processing rather than command execution. Organizations should implement immediate mitigations including updating to SDL2_image version 2.0.3 or later, which contains the necessary patches to address the bounds checking issues. Additionally, applications should implement additional input validation measures, such as verifying image file integrity before processing, and restricting the types of image files that can be loaded from untrusted sources. Network-based mitigations should include content filtering to prevent the delivery of potentially malicious PCX files, while application-level protections should enforce strict memory access controls and implement proper error handling for image processing operations.