CVE-2018-25013 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 ShiftBytes. 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-2018-25013 represents a critical out-of-bounds read flaw within the libwebp library version 1.0.0 and earlier. This library serves as a fundamental component for webp image format processing across numerous applications and systems, making its security implications particularly severe. The flaw manifests specifically within the ShiftBytes function, which is responsible for handling byte-level operations during image processing. When processing malformed webp image files, the function fails to properly validate input boundaries, leading to memory access violations that can result in unpredictable behavior.
This vulnerability falls under the CWE-125 Out-of-Bounds Read category, which is classified as a fundamental memory safety issue in software development practices. The technical nature of the flaw means that an attacker could potentially craft malicious webp image files that trigger the out-of-bounds read condition when processed by vulnerable applications. The impact extends beyond simple data corruption, as the out-of-bounds memory access can expose sensitive information from adjacent memory locations, thereby compromising data confidentiality. Additionally, the vulnerability can lead to service availability issues when applications crash or behave unpredictably upon encountering malformed input, creating potential denial-of-service conditions.
The operational impact of this vulnerability is substantial given that libwebp is widely integrated into web browsers, image processing applications, and content management systems. Attackers could exploit this weakness through various attack vectors including web-based image uploads, email attachments, or any system that processes webp images without proper input validation. The vulnerability aligns with ATT&CK technique T1203, which involves gaining access to system resources through software exploitation. Systems utilizing vulnerable versions of libwebp may experience unauthorized data disclosure, application instability, or complete service disruption depending on how the vulnerability is exploited.
Mitigation strategies should prioritize immediate upgrading to libwebp version 1.0.1 or later, which contains the necessary patches to address the out-of-bounds read condition. Organizations should implement comprehensive input validation mechanisms for all image file processing, particularly when handling user-uploaded content. Additional protective measures include deploying web application firewalls, implementing strict file type validation, and conducting regular security assessments of image processing pipelines. The fix addresses the root cause by adding proper boundary checks within the ShiftBytes function, ensuring that all memory accesses remain within allocated buffer limits and preventing unauthorized memory access patterns that could compromise system integrity or confidentiality.