CVE-2016-7449 in GraphicsMagick
Summary
by MITRE
The TIFFGetField function in coders/tiff.c in GraphicsMagick 1.3.24 allows remote attackers to cause a denial of service (out-of-bounds heap read) via a file containing an "unterminated" string.
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Analysis
by VulDB Data Team • 11/11/2022
The vulnerability identified as CVE-2016-7449 represents a critical heap-based out-of-bounds read flaw within GraphicsMagick's TIFF image processing library. This issue exists in the TIFFGetField function located in the coders/tiff.c source file of GraphicsMagick version 1.3.24, making it susceptible to remote exploitation by malicious actors who craft specially malformed TIFF files. The vulnerability stems from insufficient input validation when processing TIFF metadata, specifically when encountering "unterminated" string sequences within the file structure. The flaw allows attackers to manipulate the parsing logic by introducing malformed data that bypasses normal boundary checks, leading to memory access violations that can result in application crashes or system instability.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where programs access memory locations beyond the intended buffer boundaries. When GraphicsMagick processes a malformed TIFF file containing an unterminated string, the TIFFGetField function fails to properly validate the string termination markers, causing the parser to read beyond allocated heap memory regions. This particular implementation flaw demonstrates a classic buffer over-read scenario where the application's string parsing logic does not account for edge cases in malformed input data, particularly when dealing with variable-length string fields within TIFF metadata structures. The vulnerability operates at the intersection of input validation and memory management, where insufficient bounds checking allows arbitrary memory access patterns that can be exploited for denial of service attacks.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged in broader attack chains targeting web applications and services that utilize GraphicsMagick for image processing. Remote attackers can craft malicious TIFF files that, when processed by vulnerable systems, trigger heap corruption and application crashes, effectively creating a denial of service condition that can be exploited at scale. The vulnerability is particularly concerning in environments where GraphicsMagick is used as part of content management systems, web applications, or file processing pipelines, as it can be triggered through simple file uploads or image processing workflows. Attackers can potentially exploit this weakness to cause persistent service degradation, resource exhaustion, or even information disclosure if the out-of-bounds read reveals sensitive memory contents. This vulnerability also maps to ATT&CK technique T1203, which describes exploitation of software vulnerabilities for denial of service, and T1059, which involves command and control through application execution.
Mitigation strategies for CVE-2016-7449 should focus on immediate patching of GraphicsMagick installations to versions that address the buffer over-read condition in TIFF parsing. System administrators should implement input validation measures at network boundaries, including content filtering and file type verification for image uploads to prevent malicious TIFF files from reaching vulnerable applications. Additionally, deploying application sandboxing and memory protection mechanisms such as stack canaries, address space layout randomization, and heap integrity checks can help reduce the exploitability of similar vulnerabilities. Organizations should also consider implementing network segmentation and monitoring for unusual file processing patterns that might indicate exploitation attempts. Regular security assessments and vulnerability scanning of image processing pipelines are essential to identify and remediate similar issues before they can be exploited in real-world scenarios, particularly given the widespread use of GraphicsMagick in enterprise environments and web applications where image handling is a common requirement.