CVE-2018-8807 in libming
Summary
by MITRE
In libming 0.4.8, these is a use-after-free in the function decompileCALLFUNCTION of decompile.c. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted swf file.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 02/22/2023
The vulnerability identified as CVE-2018-8807 represents a critical use-after-free flaw within the libming library version 0.4.8, specifically within the decompileCALLFUNCTION function located in the decompile.c source file. This library serves as a SWF (Small Web Format) file manipulation tool that allows developers and security researchers to parse, modify, and analyze Shockwave Flash files. The flaw occurs during the decompilation process when handling malformed SWF files, creating a scenario where memory previously freed by the application is accessed again, leading to unpredictable behavior and potential system instability.
The technical nature of this vulnerability places it squarely within the CWE-416 category of use-after-free conditions, which is classified as a common weakness in software security. When a remote attacker crafts a malicious SWF file that triggers the decompileCALLFUNCTION function, the library fails to properly validate input data structures before attempting to access memory that has already been deallocated. This memory corruption scenario can result in application crashes, memory corruption, or potentially more severe consequences depending on the execution environment and the specific memory layout at the time of the access violation.
The operational impact of CVE-2018-8807 extends beyond simple denial of service, as it represents a potential vector for more sophisticated attacks within systems that rely on libming for SWF file processing. Systems that automatically process or analyze SWF files, such as web applications, content management systems, or security analysis platforms that handle Flash content, become vulnerable to exploitation. The remote exploitation capability means that attackers can trigger this vulnerability without requiring local access to the target system, making it particularly dangerous in web-facing applications where SWF files might be uploaded or processed automatically.
From an ATT&CK framework perspective, this vulnerability aligns with the technique of "Exploitation for Defense Evasion" and "Command and Control" when considering how attackers might leverage such flaws to establish persistent access or disrupt services. The vulnerability can be classified under the tactic of "Execution" as it allows for arbitrary code execution through memory corruption. Additionally, it relates to "Persistence" mechanisms when considering that successful exploitation could allow attackers to maintain access to compromised systems through the continued processing of malicious SWF content.
Mitigation strategies for CVE-2018-8807 should prioritize immediate patching of the libming library to version 0.4.9 or later, which contains the necessary fixes for the use-after-free condition. Organizations should implement strict input validation for all SWF file processing, including signature verification and content sanitization before any decompilation operations. Network-based mitigations such as content filtering and web application firewalls should be deployed to prevent the delivery of potentially malicious SWF files to systems that process such content. Additionally, security monitoring should be enhanced to detect unusual patterns in SWF file processing that might indicate exploitation attempts. The vulnerability highlights the importance of memory safety practices and proper input validation in libraries that process untrusted binary data, particularly in legacy formats like SWF that continue to be encountered in enterprise environments despite the decline in Flash support.