CVE-2018-15870 in libming
Summary
by MITRE
An invalid memory address dereference was discovered in decompileGETVARIABLE in libming 0.4.8 before 2018-03-12. The vulnerability causes a segmentation fault and application crash, which leads to denial of service.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-15870 represents a critical memory safety issue within the libming library version 0.4.8 and earlier releases. This flaw exists in the decompileGETVARIABLE function which is responsible for processing certain SWF file structures during the decompilation process. The vulnerability manifests as an invalid memory address dereference that occurs when the library attempts to access memory locations that have not been properly allocated or validated. This type of error falls under the category of memory corruption vulnerabilities that can severely impact application stability and security posture.
The technical nature of this vulnerability stems from inadequate input validation within the decompileGETVARIABLE function. When processing malformed or specially crafted SWF files, the library fails to properly verify memory pointers before dereferencing them, leading to a segmentation fault. This memory access violation causes the application to crash immediately upon encountering the malformed input, resulting in a complete denial of service condition. The vulnerability is particularly concerning because it can be triggered through user-supplied input, making it exploitable in scenarios where applications process untrusted SWF content. This flaw aligns with CWE-476 which specifically addresses NULL pointer dereference conditions, though the exact manifestation involves invalid memory addresses rather than null pointers.
From an operational perspective, this vulnerability creates significant risk for applications that rely on libming for SWF file processing or conversion. Systems using this library may experience unexpected crashes when handling SWF files from untrusted sources, potentially leading to service disruption and availability issues. The denial of service impact extends beyond simple application crashes to encompass potential system instability, especially in environments where multiple processes depend on stable SWF processing capabilities. Attackers could exploit this vulnerability by crafting malicious SWF files designed to trigger the memory access violation, thereby causing legitimate applications to become unresponsive or terminate unexpectedly. This vulnerability directly impacts the availability and reliability of systems that process Flash content, particularly in web applications, content management systems, or digital asset processing platforms.
Mitigation strategies for CVE-2018-15870 should prioritize immediate patching of the libming library to version 0.4.8 or later, which contains the necessary fixes for the memory access violation. Organizations should implement input validation measures to sanitize SWF file content before processing, particularly when dealing with user-uploaded or externally sourced files. Network-based protections can include implementing content filtering mechanisms that identify and block potentially malicious SWF files based on known patterns or signatures. Additionally, application-level defenses should incorporate proper error handling and graceful degradation mechanisms to prevent complete system crashes when malformed input is encountered. System administrators should also consider implementing monitoring and alerting for application crashes or unexpected terminations that may indicate exploitation attempts. The vulnerability demonstrates the importance of regular security updates and the need for comprehensive testing of third-party libraries to identify and remediate memory safety issues before they can be exploited in real-world scenarios. Organizations should also consider implementing sandboxing techniques when processing untrusted SWF content to isolate potential impacts of such vulnerabilities.