CVE-2016-9538 in macOS
Summary
by MITRE
tools/tiffcrop.c in libtiff 4.0.6 reads an undefined buffer in readContigStripsIntoBuffer() because of a uint16 integer overflow. Reported as MSVR 35100.
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Analysis
by VulDB Data Team • 10/07/2024
The vulnerability identified as CVE-2016-9538 resides within the libtiff library version 4.0.6, specifically in the tools/tiffcrop.c file where the readContigStripsIntoBuffer() function exhibits problematic behavior due to an integer overflow issue. This flaw occurs when processing TIFF image files and represents a critical security concern that can potentially lead to arbitrary code execution or system compromise. The vulnerability manifests as an undefined buffer read operation that stems from improper handling of uint16 integer arithmetic, creating a scenario where memory access patterns become unpredictable and potentially exploitable.
The technical root cause of this vulnerability can be traced to a classic integer overflow condition within the uint16 data type handling. When the readContigStripsIntoBuffer() function processes image data, it performs calculations that can exceed the maximum value representable by a 16-bit unsigned integer, which is 65535. This overflow condition causes the function to access memory locations beyond the intended buffer boundaries, resulting in undefined behavior and potential memory corruption. The vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which is classified as a fundamental weakness in software design that can lead to various security implications including buffer overflows and memory corruption issues.
From an operational perspective, this vulnerability poses significant risks to systems that process TIFF image files using the affected libtiff library version. Attackers can craft malicious TIFF files that trigger the integer overflow condition during image processing operations, potentially leading to denial of service conditions, information disclosure, or even remote code execution depending on the system architecture and memory layout. The impact extends across various applications that depend on libtiff for image processing, including graphic design software, document management systems, and digital imaging platforms that handle user-uploaded content. This vulnerability aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for privilege escalation and system compromise.
The mitigation strategies for CVE-2016-9538 primarily involve immediate patching of the libtiff library to version 4.0.7 or later, which contains the necessary fixes to address the integer overflow condition. Organizations should also implement input validation measures that restrict the size and format of TIFF files processed by applications, particularly those handling untrusted user content. Additional defensive measures include deploying sandboxing techniques for image processing operations and implementing network segmentation to limit the potential impact of exploitation. Security monitoring should focus on detecting unusual image processing activities that might indicate exploitation attempts, while regular vulnerability assessments should be conducted to identify other potential integer overflow conditions in similar libraries and applications. The fix implemented in the patched version addresses the specific uint16 overflow by introducing proper bounds checking and ensuring that arithmetic operations remain within safe integer ranges, preventing the undefined buffer read behavior that characterized the original vulnerability.