CVE-2016-6328 in libexif
Summary
by MITRE
A vulnerability was found in libexif. An integer overflow when parsing the MNOTE entry data of the input file. This can cause Denial-of-Service (DoS) and Information Disclosure (disclosing some critical heap chunk metadata, even other applications' private data).
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Analysis
by VulDB Data Team • 06/04/2023
The vulnerability identified as CVE-2016-6328 resides within the libexif library, a widely used component for parsing exchangeable image file format metadata in various applications and systems. This library serves as a critical dependency for numerous image processing tools, operating systems, and security applications that handle jpeg files containing exif metadata. The flaw manifests as an integer overflow condition that occurs during the parsing of MNOTE entry data structures within image files, representing a fundamental issue in how the library handles malformed input data. The vulnerability is classified under CWE-190 as an integer overflow, which is a well-documented weakness in software systems where arithmetic operations exceed the maximum value that can be represented by the target data type. This specific implementation flaw affects the memory management aspects of the library, particularly when processing specially crafted exif data structures that contain oversized or malformed MNOTE entries.
The technical execution of this vulnerability involves the manipulation of integer variables during the parsing process of exif metadata fields, where an attacker can craft image files containing maliciously formatted MNOTE entries that trigger arithmetic overflow conditions. When the libexif library attempts to process these malformed entries, the integer overflow causes unpredictable behavior in the memory allocation and management routines. The overflow specifically impacts the calculation of buffer sizes or array dimensions, leading to situations where the library allocates insufficient memory or calculates incorrect memory offsets. This flaw can be exploited by adversaries who understand the exif format structure and can construct files that will trigger the overflow condition, potentially causing the application to crash or behave unpredictably. The vulnerability's impact extends beyond simple application crashes, as the integer overflow can result in information disclosure through heap metadata exposure, where critical memory layout information becomes accessible to attackers.
The operational consequences of CVE-2016-6328 present significant risks to systems that rely on libexif for image processing, including but not limited to web applications, digital asset management systems, image editing software, and security tools that analyze image files. The denial-of-service aspect can be leveraged by attackers to disrupt services by causing applications to crash or become unresponsive when processing malicious image files, potentially leading to service degradation or complete system outages. More critically, the information disclosure component poses substantial privacy and security risks as heap metadata and potentially sensitive application data can be exposed through memory corruption artifacts. This exposure can lead to the leakage of private information from other applications running on the same system, creating potential attack vectors for further exploitation. The vulnerability's impact is amplified in environments where image processing is automated or where applications automatically process user-uploaded content without proper validation or sandboxing mechanisms.
Mitigation strategies for this vulnerability should focus on immediate patching of affected libexif versions, as the primary solution involves updating to patched versions that properly handle integer overflow conditions in the MNOTE entry parsing logic. Organizations should implement comprehensive input validation for all image files processed through systems that utilize libexif, including the use of sandboxed environments for image processing and implementing strict file format validation before any metadata parsing occurs. Network security controls such as intrusion detection systems can be configured to monitor for suspicious image file patterns that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1203 as Exploitation for Client Execution, highlighting the need for defensive measures against client-side exploitation vectors. Additionally, application developers should consider implementing proper error handling and memory management practices in their own code to prevent cascading failures when interacting with vulnerable libraries, including the use of memory safety features and proper resource cleanup mechanisms. Regular security assessments and vulnerability scanning should be conducted to identify systems that may still be running vulnerable versions of libexif or related software components that could be exploited through this integer overflow condition.