CVE-2017-9989 in libming
Summary
by MITRE
util/outputtxt.c in libming 0.4.8 mishandles memory allocation. A crafted input will lead to a remote denial of service (NULL pointer dereference) attack.
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Analysis
by VulDB Data Team • 12/09/2022
The vulnerability identified as CVE-2017-9989 resides within the libming library version 0.4.8, specifically in the util/outputtxt.c module where improper memory allocation handling creates a critical security flaw. This issue manifests when the library processes crafted input data that triggers a NULL pointer dereference condition during the text output processing phase. The libming library serves as a software development kit for creating flash content and is commonly utilized in applications requiring swf file generation and manipulation. The flaw occurs during the memory management process when the application attempts to allocate memory for text output operations without proper validation of allocation success, leading to a scenario where subsequent memory access operations attempt to dereference a NULL pointer.
The technical implementation of this vulnerability stems from inadequate error handling within the memory allocation routines of the outputtxt.c component. When processing malformed input data, the library fails to verify whether memory allocation functions return valid pointers before proceeding with operations that assume successful allocation. This pattern directly aligns with CWE-476 which describes NULL pointer dereference vulnerabilities, where a null pointer is dereferenced without proper validation. The vulnerability can be exploited remotely through input manipulation, making it particularly dangerous for web applications or services that utilize libming for processing user-provided content or file uploads. The remote denial of service condition occurs because the application crashes when attempting to access memory through a NULL pointer, effectively terminating the service and rendering it unavailable to legitimate users.
The operational impact of CVE-2017-9989 extends beyond simple service disruption to encompass potential system stability issues and resource exhaustion. Attackers can craft specific input sequences that will consistently trigger the NULL pointer dereference, leading to repeated service crashes and potential denial of service conditions for legitimate users. This vulnerability particularly affects applications that process untrusted input data through the libming library, including web applications, content management systems, and file processing utilities that generate flash content. The exploitability of this vulnerability is relatively straightforward since it requires only the creation of malicious input data that will trigger the memory allocation failure. The attack vector operates through the standard input processing pathways, making it difficult to detect and prevent without proper input validation and library updates.
Mitigation strategies for this vulnerability should prioritize immediate library version updates to address the memory allocation handling issues present in libming 0.4.8. Organizations should implement comprehensive input validation measures that filter or sanitize all data processed through the affected library components. The implementation of proper error handling routines within applications that utilize libming can provide additional protection against exploitation attempts. Security practitioners should consider deploying intrusion detection systems that monitor for patterns consistent with this vulnerability's exploitation attempts and implement network segmentation to limit potential attack surface areas. Additionally, the vulnerability demonstrates the importance of adhering to secure coding practices as outlined in the software security principles that prevent NULL pointer dereference conditions through proper validation and error handling mechanisms. Organizations should also consider implementing application whitelisting controls and regular security assessments to identify similar memory management issues in other third-party libraries and components.