CVE-2018-13250 in libming
Summary
by MITRE
libming 0.4.8 has a NULL pointer dereference in the getString function of the decompile.c file, related to decompileSTRINGCONCAT. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted swf file.
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Analysis
by VulDB Data Team • 04/03/2023
The vulnerability identified as CVE-2018-13250 resides within the libming library version 0.4.8, specifically in the decompile.c file where the getString function exhibits a critical NULL pointer dereference behavior. This flaw occurs during the processing of SWF (Small Web Format) files, particularly when handling decompileSTRINGCONCAT operations that involve string concatenation within Flash multimedia content. The issue manifests when the library attempts to process malformed or crafted SWF files that contain specially constructed string data structures, leading to an unhandled NULL reference that causes the application to crash. The vulnerability represents a classic denial of service condition where legitimate system resources become unavailable due to the application's failure to properly validate input data structures. This type of flaw falls under the CWE-476 category of NULL Pointer Dereference, which is a well-documented weakness in software security that can lead to system instability and service disruption. The attack vector is remote and requires only the delivery of a malicious SWF file to the target system, making it particularly dangerous in web environments where users might unknowingly encounter such content.
The technical exploitation of this vulnerability occurs during the decompilation process of SWF files, where the getString function fails to properly validate pointer references before attempting to dereference them. When the decompileSTRINGCONCAT operation encounters a malformed string reference, the function does not perform adequate null checks, resulting in a segmentation fault or access violation that terminates the application process. This behavior is consistent with improper input validation patterns commonly found in multimedia processing libraries that handle complex binary formats. The vulnerability demonstrates a lack of defensive programming practices where the code assumes certain data structures will always contain valid references, without implementing proper error handling for malformed input. The impact extends beyond simple application crashes as it can be leveraged by attackers to repeatedly disrupt services through repeated exploitation, potentially leading to resource exhaustion or system instability in environments where libming is used for automated SWF processing or content analysis.
From an operational perspective, this vulnerability poses significant risks to organizations that utilize libming for SWF file processing, particularly in web applications, content management systems, or security analysis tools that handle untrusted Flash content. The remote nature of the attack means that adversaries can exploit this vulnerability without requiring local system access, making it especially dangerous in multi-tenant environments or public-facing applications. The denial of service impact can be severe in systems where SWF processing is critical to operations, potentially affecting user experience, system availability, or automated content analysis workflows. Security professionals should consider this vulnerability as part of their broader threat landscape, as it aligns with attack patterns described in the ATT&CK framework under the T1499 category of Network Denial of Service, where attackers seek to disrupt services through resource exhaustion or application crashes. Organizations using affected versions of libming should prioritize patching and implement additional input validation measures to prevent exploitation.
Mitigation strategies for CVE-2018-13250 should focus on immediate remediation through version updates to libming 0.4.9 or later, which contain the necessary patches to address the NULL pointer dereference issue. Additionally, organizations should implement input validation controls that filter or sanitize SWF content before processing, particularly in web applications that accept user-uploaded Flash files. Network-level defenses can include content filtering solutions that detect and block suspicious SWF files, while application-level protections should enforce proper error handling and input validation routines to prevent the propagation of malformed data through the system. Security monitoring should include detection of application crashes or unexpected terminations that could indicate exploitation attempts, and incident response procedures should be updated to address potential denial of service scenarios involving multimedia processing libraries. The vulnerability serves as a reminder of the importance of defensive programming practices and the need for comprehensive testing of edge cases in software libraries that handle complex binary formats, particularly those used in security-sensitive environments where robustness and reliability are paramount.