CVE-2015-0848 in libwmf
Summary
by MITRE
Heap-based buffer overflow in libwmf 0.2.8.4 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via a crafted BMP image.
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Analysis
by VulDB Data Team • 05/22/2022
The vulnerability identified as CVE-2015-0848 represents a critical heap-based buffer overflow within the libwmf library version 0.2.8.4, which serves as a crucial component for handling windows metafile format graphics in various applications. This library functions as a bridge between different graphics formats and is widely integrated into software systems for rendering vector graphics and metafiles. The flaw specifically manifests when processing malformed BMP image files, creating a dangerous condition that can be exploited remotely by malicious actors to compromise system integrity and availability. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations.
The technical mechanism behind this vulnerability involves improper input validation within the libwmf library's BMP parsing routines. When a crafted BMP image is processed, the library fails to properly validate the dimensions and data structure of the image file, leading to a situation where memory allocation occurs based on unreliable input values. This allows an attacker to manipulate the heap memory layout by providing specially constructed data that exceeds the allocated buffer boundaries. The overflow can result in memory corruption that manifests as application crashes or more severe consequences including arbitrary code execution. The vulnerability's exploitation potential is heightened by the fact that libwmf is used across multiple platforms and applications, making the attack surface significantly broader than initially apparent. The heap corruption can be leveraged to manipulate program execution flow through techniques such as return-oriented programming or direct memory overwrite attacks, which aligns with tactics described in the MITRE ATT&CK framework under the 'Execution' and 'Persistence' domains.
The operational impact of this vulnerability extends far beyond simple denial of service scenarios, as it can compromise the entire system stability and security posture of affected environments. Applications that rely on libwmf for graphics processing become vulnerable to remote code execution when they encounter maliciously crafted BMP files, potentially allowing attackers to gain unauthorized access to systems and escalate privileges. The vulnerability affects not only desktop applications but also server-side systems that process user-uploaded graphics files, creating a significant risk for web applications and content management systems. Organizations utilizing software that incorporates this library must consider the potential for complete system compromise, especially in environments where automatic image processing is enabled. The vulnerability's classification as a heap-based buffer overflow also makes it particularly susceptible to exploitation through modern exploit techniques that leverage memory corruption to achieve code execution without requiring user interaction beyond the initial image processing event.
Mitigation strategies for CVE-2015-0848 require immediate action to address the underlying library vulnerability through software updates and patches. System administrators should prioritize upgrading to libwmf versions that contain the necessary fixes, as the original vulnerable version 0.2.8.4 is no longer maintained and lacks security updates. Additionally, implementing input validation controls at multiple levels can provide defense-in-depth measures, including filtering BMP files before processing, limiting file size constraints, and employing sandboxing techniques to isolate graphics processing operations. Network-based mitigations such as implementing web application firewalls and content filtering systems can help prevent malicious BMP files from reaching vulnerable applications. Organizations should also consider disabling automatic image processing for untrusted content and implementing strict access controls for graphics handling components. The remediation process should include comprehensive testing of patched applications to ensure compatibility and prevent regression issues while maintaining the security improvements. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable library within the system environment, as the vulnerability may be present in multiple components or third-party applications that depend on libwmf for their functionality.