CVE-2018-25009 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-2018-25009 represents a critical out-of-bounds read flaw within the libwebp library version 1.0.0 and earlier. This issue specifically manifests in the WebPMuxCreateInternal function, which is responsible for creating WebP image format muxing operations. The flaw occurs when processing malformed or crafted WebP files that contain improperly structured metadata or image data. Such out-of-bounds memory access can lead to unpredictable behavior and potential exploitation by malicious actors.
This vulnerability falls under the Common Weakness Enumeration category CWE-125, which describes out-of-bounds read conditions where a program accesses memory beyond the boundaries of a buffer. The technical implementation flaw stems from insufficient input validation and boundary checking within the WebPMuxCreateInternal function. When the library processes WebP files with malformed structures, particularly those containing crafted metadata or image headers, the function fails to properly validate array indices or buffer limits before accessing memory locations. This lack of proper bounds checking creates an opportunity for attackers to manipulate input data to trigger memory access violations.
The operational impact of CVE-2018-25009 extends beyond simple service disruption to encompass significant data confidentiality risks. When exploited, this vulnerability can potentially allow attackers to read sensitive memory contents that may include cryptographic keys, user credentials, or application data. The service availability threat is particularly concerning as the out-of-bounds read can cause application crashes or system instability, leading to denial of service conditions. Systems that process untrusted WebP image files, such as web servers, content management systems, or image processing applications, become vulnerable to both availability attacks and information disclosure threats.
The vulnerability is particularly dangerous in environments where libwebp is used for processing user-uploaded content or when integrated into web applications that handle external image sources. Attackers could craft malicious WebP files that trigger the out-of-bounds read condition, potentially leading to information leakage or system compromise. The threat model aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, where attackers might leverage such memory corruption vulnerabilities to execute arbitrary code or escalate privileges. Organizations using vulnerable versions of libwebp should immediately implement mitigation strategies including updating to version 1.0.1 or later, implementing input validation for WebP files, and deploying intrusion detection systems to monitor for exploitation attempts.
Security practitioners should consider this vulnerability in the context of broader memory safety issues and implement comprehensive patch management procedures. The fix in libwebp 1.0.1 addresses the root cause by adding proper bounds checking and input validation mechanisms. Additionally, organizations should perform vulnerability assessments to identify all systems utilizing affected libwebp versions and establish monitoring procedures to detect potential exploitation attempts. The vulnerability demonstrates the importance of rigorous input validation and memory safety practices in multimedia processing libraries, which are increasingly targeted by attackers seeking to exploit memory corruption vulnerabilities in widely used software components.