CVE-2018-25012 in libwebp
Summary
by MITRE • 05/21/2021
A flaw was found in libwebp in versions before 1.0.1. An out-of-bounds read was found in function WebPMuxCreateInternal. The highest threat from this vulnerability is to data confidentiality and to the service availability.
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Analysis
by VulDB Data Team • 05/23/2021
The vulnerability identified as CVE-2018-25012 represents a critical out-of-bounds read flaw within the libwebp library version 1.0.0 and earlier. This issue manifests specifically within the WebPMuxCreateInternal function, which is responsible for creating WebP multiplexed image containers. The flaw arises from insufficient input validation and boundary checking during the processing of WebP format data structures, creating a scenario where maliciously crafted input can trigger memory access violations beyond the allocated buffer boundaries. This vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can lead to information disclosure and system instability.
The technical exploitation of this vulnerability occurs when applications processing WebP images fail to properly validate input data before passing it to the WebPMuxCreateInternal function. An attacker can craft a specially formatted WebP file that contains malformed metadata or incorrect data structures, causing the library to read memory locations that are outside the intended buffer boundaries. This out-of-bounds memory access can result in the disclosure of sensitive information from adjacent memory regions, potentially exposing cryptographic keys, user credentials, or other confidential data stored in memory. The vulnerability's impact extends beyond mere information disclosure, as it can also lead to service availability issues through application crashes or denial of service conditions.
From an operational perspective, the threat posed by CVE-2018-25012 is particularly concerning given the widespread adoption of libwebp across various software platforms and applications. The vulnerability affects web browsers, image processing applications, and any software that relies on libwebp for handling WebP image formats, making it a prime target for exploitation in web-based attacks. The attack surface is broad as WebP format support is integrated into many modern applications, including content management systems, image editing tools, and web servers processing user-uploaded media files. The vulnerability's classification under the ATT&CK framework's T1203 technique for "Exploitation for Client Execution" highlights its potential for remote code execution when combined with other exploit primitives, though the direct execution path remains limited by the nature of the out-of-bounds read.
Mitigation strategies for CVE-2018-25012 primarily focus on updating to libwebp version 1.0.1 or later, which contains the necessary patches to address the boundary checking deficiencies. System administrators should prioritize patching all affected applications and services that utilize libwebp, particularly those handling untrusted image input from users. Additional defensive measures include implementing strict input validation and sanitization for all image processing workflows, deploying web application firewalls to filter suspicious image uploads, and establishing monitoring protocols to detect potential exploitation attempts. The vulnerability demonstrates the importance of robust memory safety practices in multimedia libraries and highlights the need for comprehensive security testing of image processing components to prevent similar issues in the future.