CVE-2018-4868 in Exiv2
Summary
by MITRE
The Exiv2::Jp2Image::readMetadata function in jp2image.cpp in Exiv2 0.26 allows remote attackers to cause a denial of service (excessive memory allocation) via a crafted file.
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Analysis
by VulDB Data Team • 01/20/2023
The vulnerability identified as CVE-2018-4868 resides within the Exiv2 library version 0.26, specifically in the Exiv2::Jp2Image::readMetadata function located in the jp2image.cpp source file. This flaw represents a classic denial of service vulnerability that can be exploited remotely through crafted image files, potentially causing systems to consume excessive memory resources and ultimately leading to system instability or unresponsiveness. The vulnerability affects applications that utilize Exiv2 for reading image metadata, particularly those processing jpeg2000 format files where the library's JP2 image handling functionality is invoked.
The technical nature of this vulnerability stems from inadequate input validation and memory management within the jpeg2000 image parsing routine. When a maliciously crafted jpeg2000 file is processed by the Exiv2 library, the readMetadata function fails to properly validate the file structure and size parameters, leading to unbounded memory allocation requests. This occurs because the function does not implement proper bounds checking on the metadata fields or image dimensions that could be manipulated by an attacker to trigger excessive memory consumption. The flaw operates at the level of resource exhaustion rather than code execution, making it particularly dangerous in environments where memory resources are constrained or where the vulnerable applications are exposed to untrusted input from external sources.
The operational impact of CVE-2018-4868 extends beyond simple service disruption, as it can affect a wide range of applications and systems that depend on Exiv2 for image metadata processing. This includes content management systems, digital asset management platforms, image processing pipelines, and any software that handles user-uploaded images. The vulnerability is particularly concerning in web applications where users can upload images, as it provides a straightforward path for remote attackers to consume system resources and potentially cause cascading failures in applications that do not implement proper resource limits or memory constraints. The memory exhaustion can lead to application crashes, system slowdowns, or even complete system hangs depending on the implementation environment and available resources.
From a cybersecurity perspective, this vulnerability aligns with CWE-770, which describes the allocation of resources without limits or with inadequate limits, and relates to the broader category of resource exhaustion attacks. The attack pattern follows the techniques described in the MITRE ATT&CK framework under the T1499.004 sub-technique for network denial of service, where adversaries leverage resource exhaustion to disrupt services. Organizations should implement proper input validation and resource monitoring to detect and prevent exploitation attempts. The recommended mitigation strategy involves upgrading to Exiv2 version 0.27 or later, where this vulnerability has been addressed through improved bounds checking and memory allocation controls. Additionally, system administrators should consider implementing resource limits on applications that process image files, deploying intrusion detection systems to monitor for unusual memory consumption patterns, and ensuring proper input sanitization before any image processing occurs to prevent exploitation attempts.