CVE-2018-20098 in Exiv2
Summary
by MITRE
There is a heap-based buffer over-read in Exiv2::Jp2Image::encodeJp2Header of jp2image.cpp in Exiv2 0.27-RC3. A crafted input will lead to a remote denial of service attack.
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Analysis
by VulDB Data Team • 06/18/2023
The vulnerability identified as CVE-2018-20098 represents a critical heap-based buffer over-read flaw within the Exiv2 image processing library version 0.27-RC3. This issue resides in the Exiv2::Jp2Image::encodeJp2Header function located in the jp2image.cpp source file, where improper input validation allows maliciously crafted JPEG 2000 image data to trigger memory access violations. The flaw specifically manifests when the library attempts to process malformed JP2 headers without adequate bounds checking, leading to unauthorized memory reads beyond allocated buffer boundaries.
The technical exploitation of this vulnerability occurs through the manipulation of JPEG 2000 image files that contain specially constructed header data. When the Exiv2 library processes such malformed inputs during the JP2 header encoding phase, the buffer over-read condition causes the application to access memory locations that were not properly allocated for the operation. This memory access violation typically results in application crashes, segmentation faults, or unpredictable behavior that can be leveraged for remote denial of service attacks. The vulnerability is particularly dangerous because it can be triggered through any application that relies on Exiv2 for image metadata processing, including web applications, content management systems, and image processing tools.
From an operational perspective, this vulnerability poses significant risks to systems that process untrusted image data from external sources. Attackers can craft malicious JPEG 2000 files that, when processed by vulnerable applications, will cause the target system to crash or become unresponsive, effectively creating a denial of service condition. The impact extends beyond individual application failures to potentially affect entire service availability, especially in environments where Exiv2 is used as a core component for image handling. The vulnerability affects a wide range of applications including web servers, image processing pipelines, and content management platforms that utilize Exiv2 for metadata extraction and image validation.
Security practitioners should prioritize immediate mitigation of this vulnerability through software updates to Exiv2 version 0.27 or later, which contain the necessary patches to address the buffer over-read condition. Additionally, implementing input validation measures and sanitization of image files before processing can provide defense-in-depth protection. Organizations should also consider deploying network-based intrusion detection systems that can identify and block suspicious image file patterns associated with this vulnerability. The flaw aligns with CWE-125, which describes out-of-bounds read vulnerabilities, and represents a typical example of how improper memory management can lead to remote exploitation. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to network denial of service attacks, as it enables adversaries to disrupt service availability through crafted input manipulation.