CVE-2018-13066 in libming
Summary
by MITRE
There is a memory leak in util/parser.c in libming 0.4.8, which will lead to a denial of service via parseSWF_DEFINEBUTTON2, parseSWF_DEFINEFONT, parseSWF_DEFINEFONTINFO, parseSWF_DEFINELOSSLESS, parseSWF_DEFINESPRITE, parseSWF_DEFINETEXT, parseSWF_DOACTION, parseSWF_FILLSTYLEARRAY, parseSWF_FRAMELABEL, parseSWF_LINESTYLEARRAY, parseSWF_PLACEOBJECT2, or parseSWF_SHAPEWITHSTYLE.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability identified as CVE-2018-13066 represents a critical memory leak within the libming library version 0.4.8, specifically affecting the util/parser.c component. This memory leak occurs during the parsing of various SWF file elements including button definitions, font definitions, lossless image data, sprite definitions, text elements, action execution commands, and shape styling information. The flaw manifests when the library processes SWF files containing these specific elements, leading to progressive memory consumption that ultimately results in system resource exhaustion.
The technical root cause of this vulnerability lies in improper memory management within the parser functions that handle SWF file structure elements. When the parser encounters elements such as parseSWF_DEFINEBUTTON2, parseSWF_DEFINEFONT, or parseSWF_DEFINESPRITE, it allocates memory for processing these structures but fails to properly release the allocated memory blocks upon completion of parsing operations. This memory leak pattern is classified under CWE-401 as "Improper Release of Memory Before Removing Last Reference" and represents a classic example of resource exhaustion that can be exploited by malicious actors.
The operational impact of this vulnerability extends beyond simple performance degradation to constitute a serious denial of service risk. An attacker who can influence the parsing of SWF files through a vulnerable application can systematically consume available memory resources until the system becomes unresponsive or crashes entirely. This makes the vulnerability particularly dangerous in web applications, content management systems, or any environment where SWF files are processed or validated. The attack surface is broad since SWF files are commonly used in web applications, multimedia presentations, and interactive content delivery systems.
The exploitation of this vulnerability requires an attacker to craft or obtain SWF files containing the specific parsing elements mentioned in the vulnerability description. When these files are processed by applications relying on libming 0.4.8, the memory leak compounds with each parsing operation, eventually leading to system instability or complete service disruption. This vulnerability aligns with ATT&CK technique T1499.004 which covers "Endpoint Denial of Service" through resource exhaustion attacks.
Mitigation strategies for CVE-2018-13066 primarily involve upgrading to a patched version of the libming library where the memory leak has been addressed. System administrators should also implement monitoring for unusual memory consumption patterns in applications processing SWF files. Additionally, input validation and sanitization measures can help reduce the risk by limiting the exposure to malformed SWF content. Organizations should consider implementing resource limits and timeouts for SWF processing operations to prevent complete system exhaustion even if the vulnerability is not immediately patched. The fix typically involves ensuring proper memory deallocation in all parser functions that handle SWF elements, particularly those related to button definitions, font information, sprite structures, and shape styling elements.