CVE-2018-9306 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 CVE-2018-9306 represents a critical out-of-bounds read condition within the Exiv2 image metadata library version 0.26. This flaw exists in the IptcData::printStructure function located in the iptc.c source file, where the software fails to properly validate input data during IPTC metadata processing. The specific issue occurs when handling IPTC data structures that do not match the expected hexadecimal value of 0x1c, creating a scenario where memory access occurs beyond the allocated buffer boundaries. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can lead to system instability or information disclosure.
The technical implementation of this vulnerability demonstrates a classic buffer over-read scenario where the IptcData::printStructure function processes IPTC metadata without adequate bounds checking for the data length field. When the software encounters IPTC data that does not conform to the expected 0x1c byte pattern, it proceeds to read memory locations that are outside the legitimate data structure boundaries. This behavior can be triggered during normal image processing operations when Exiv2 attempts to parse and display IPTC metadata from image files. The vulnerability is particularly concerning because it can be exploited through crafted IPTC metadata within image files, potentially allowing attackers to cause denial of service through application crashes or to extract sensitive information from memory through information disclosure.
From an operational perspective, this vulnerability poses significant risks to systems that rely on Exiv2 for image metadata processing, particularly in web applications, content management systems, and digital asset management platforms. The out-of-bounds read can result in application crashes that lead to denial of service conditions, affecting availability of critical services. Additionally, the information leak aspect presents potential security implications where sensitive data from memory could be inadvertently exposed to unauthorized parties. The vulnerability is classified under the ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation may involve manipulating metadata processing flows to trigger the memory access violation. Systems that process untrusted image files from external sources are particularly at risk, as attackers can craft malicious IPTC metadata to exploit this condition.
The recommended mitigation strategies for CVE-2018-9306 include immediate patching of Exiv2 to version 0.27 or later, which contains the necessary fixes for the out-of-bounds read condition. Organizations should also implement input validation measures that sanitize IPTC metadata before processing, particularly when handling files from untrusted sources. Network segmentation and access controls can help limit the impact of potential exploitation by restricting access to systems that process image metadata. Additionally, monitoring systems should be configured to detect abnormal application behavior or crashes that may indicate exploitation attempts. Security teams should also consider implementing automated vulnerability scanning that specifically targets Exiv2 installations to identify systems running vulnerable versions and prioritize remediation efforts. The fix implemented in newer versions typically involves adding proper bounds checking and input validation to ensure that memory access operations remain within legitimate data boundaries, addressing the root cause of the out-of-bounds read condition.