CVE-2017-18005 in Exiv2
Summary
by MITRE
Exiv2 0.26 has a Null Pointer Dereference in the Exiv2::DataValue::toLong function in value.cpp, related to crafted metadata in a TIFF file.
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Analysis
by VulDB Data Team • 01/19/2023
The vulnerability identified as CVE-2017-18005 represents a critical null pointer dereference flaw within the Exiv2 metadata processing library version 0.26. This issue manifests specifically within the Exiv2::DataValue::toLong function located in the value.cpp source file, creating a potential crash condition that can be triggered through manipulation of TIFF file metadata. The flaw demonstrates characteristics consistent with CWE-476, which addresses null pointer dereference vulnerabilities that occur when a program attempts to access memory through a null reference, leading to application instability and potential denial of service conditions.
The technical exploitation of this vulnerability occurs when a maliciously crafted TIFF file contains specially formatted metadata that causes the Exiv2 library to invoke the toLong function with a null pointer argument. When the library attempts to dereference this null pointer during the metadata parsing process, the application crashes due to the absence of valid memory reference. This behavior represents a classic denial of service vector that can be exploited by attackers who have the ability to influence the metadata processing of TIFF files, particularly in applications that rely on Exiv2 for image metadata handling.
The operational impact of CVE-2017-18005 extends beyond simple application crashes, as it can be leveraged in broader attack scenarios within software systems that process untrusted image metadata. Applications utilizing Exiv2 for image analysis, digital asset management, content delivery networks, or any system that processes TIFF files may become vulnerable to service disruption when encountering maliciously crafted metadata. This vulnerability particularly affects systems that automatically process or display image metadata without proper input validation, creating opportunities for attackers to cause system instability through carefully constructed TIFF file inputs.
Security practitioners should consider this vulnerability in the context of broader software supply chain risks, as Exiv2 is widely used across various applications and systems for metadata handling. The ATT&CK framework classification for this vulnerability would align with T1499.004, which addresses network denial of service, as the null pointer dereference can be triggered through network-delivered image files. Mitigation strategies should include immediate patching of affected Exiv2 versions, implementation of proper input validation for TIFF metadata processing, and deployment of sandboxed environments for image file analysis to prevent exploitation of this class of vulnerability in production systems.