CVE-2017-18233 in Exempi
Summary
by MITRE
An issue was discovered in Exempi before 2.4.4. Integer overflow in the Chunk class in XMPFiles/source/FormatSupport/RIFF.cpp allows remote attackers to cause a denial of service (infinite loop) via crafted XMP data in a .avi file.
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Analysis
by VulDB Data Team • 02/22/2023
The vulnerability identified as CVE-2017-18233 represents a critical integer overflow flaw within the Exempi library version 2.4.3 and earlier, which is widely used for handling XMP metadata in multimedia files. This issue specifically affects the Chunk class implementation within the RIFF.cpp file located in the XMPFiles/source/FormatSupport/ directory of the Exempi codebase. The flaw manifests when processing specially crafted XMP data embedded within .avi video files, creating a condition where the application fails to properly validate integer values during parsing operations. The vulnerability stems from inadequate bounds checking and overflow protection mechanisms that allow malicious actors to manipulate integer variables beyond their intended capacity, leading to unexpected program behavior.
The technical exploitation of this vulnerability occurs through the manipulation of XMP metadata within .avi container files, where attackers craft malicious data structures that trigger integer overflow conditions during the parsing process. When the Exempi library attempts to process these malformed chunks of data, the integer overflow causes the processing loop to enter an infinite state where the loop condition never properly terminates. This occurs because the overflowed integer value becomes so large that it wraps around to a smaller value, creating a persistent condition where the loop continues indefinitely without making progress. The vulnerability is classified under CWE-190 as an integer overflow condition, specifically involving signed integer overflow that leads to denial of service through infinite loops.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be leveraged by attackers to consume excessive system resources and potentially cause application crashes or system instability. When an application utilizing Exempi processes a maliciously crafted .avi file, the infinite loop consumes CPU cycles continuously without yielding control back to the operating system, effectively rendering the application unresponsive and potentially causing cascading failures in systems that depend on proper metadata handling. This vulnerability is particularly concerning in automated processing environments where batch operations or continuous monitoring systems might encounter such malformed files, leading to widespread service disruption. The ATT&CK framework categorizes this as a resource exhaustion technique under the T1499.004 sub-technique for network denial of service, where attackers manipulate application behavior to consume excessive resources.
Mitigation strategies for CVE-2017-18233 primarily involve upgrading to Exempi version 2.4.4 or later, which includes proper integer overflow protections and enhanced input validation mechanisms. Organizations should implement comprehensive patch management procedures to ensure all systems utilizing Exempi libraries receive timely updates. Additionally, implementing proper input sanitization and validation at the application level can provide defense-in-depth measures, particularly in environments where immediate patching may not be feasible. Network administrators should consider implementing file type filtering and content validation mechanisms to prevent processing of potentially malicious .avi files containing crafted XMP data. The vulnerability demonstrates the critical importance of proper integer handling in security-sensitive applications and highlights the necessity of robust bounds checking and overflow protection mechanisms in multimedia processing libraries. Organizations should also conduct regular security assessments of their software dependencies to identify and remediate similar vulnerabilities before they can be exploited in real-world scenarios.