CVE-2018-9305 in Exiv2
Summary
by MITRE
In Exiv2 0.26, an out-of-bounds read in IptcData::printStructure in iptc.c could result in a crash or information leak, related to the "== 0x1c" case.
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Analysis
by VulDB Data Team • 02/27/2023
The vulnerability identified as CVE-2018-9305 affects Exiv2 version 0.26, a widely used C++ library for reading and writing image metadata. This issue manifests as an out-of-bounds read condition within the IptcData::printStructure function in the iptc.c source file, representing a critical security flaw that can lead to system instability and potential information disclosure. The vulnerability specifically occurs in the handling of IPTC (International Press Telecommunications Council) metadata structures, which are commonly embedded in digital images to store descriptive information about photographs and other visual content.
The technical flaw stems from inadequate bounds checking within the IPTC data processing logic, particularly when encountering specific byte sequences that match the hexadecimal value 0x1c. This particular value represents a carriage return character in ASCII encoding and is used within IPTC data structures to denote specific metadata elements. When the Exiv2 library processes IPTC data containing this specific byte pattern, the printStructure function fails to properly validate array boundaries before accessing memory locations, resulting in unauthorized memory access beyond the allocated buffer space. This type of vulnerability falls under the Common Weakness Enumeration category CWE-129, which specifically addresses improper validation of array indices, and more broadly relates to CWE-125, which covers out-of-bounds read conditions.
The operational impact of this vulnerability extends beyond simple application crashes, as it can potentially enable information leakage from adjacent memory regions. An attacker who can craft malicious IPTC metadata within an image file could trigger this out-of-bounds read condition, causing the application to crash or potentially exposing sensitive data from memory locations adjacent to the targeted buffer. This makes the vulnerability particularly dangerous in environments where Exiv2 is used to process untrusted image files, such as web applications, content management systems, or digital asset management platforms. The vulnerability can be exploited through various attack vectors including email attachments, image upload functionality, or content sharing platforms where users might unknowingly trigger the malicious code execution path.
Mitigation strategies for CVE-2018-9305 should prioritize immediate patching of the Exiv2 library to version 0.27 or later, where the out-of-bounds read condition has been properly addressed through enhanced bounds checking and input validation. Organizations should implement comprehensive input sanitization measures for all IPTC metadata processing, including validating the length and structure of metadata elements before parsing. Network defenders should consider implementing sandboxing mechanisms for image processing operations and establishing strict file format validation procedures to prevent malformed IPTC data from reaching the Exiv2 library. Additionally, monitoring systems should be configured to detect unusual crash patterns or memory access anomalies in applications that utilize Exiv2 for metadata processing. This vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for privilege escalation or information gathering, and represents a critical target for security hardening efforts in digital media processing environments.