CVE-2018-12900 in LibTIFF
Summary
by MITRE
Heap-based buffer overflow in the cpSeparateBufToContigBuf function in tiffcp.c in LibTIFF 4.0.9 allows remote attackers to cause a denial of service (crash) or possibly have unspecified other impact via a crafted TIFF file.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability identified as CVE-2018-12900 represents a critical heap-based buffer overflow within the LibTIFF library version 4.0.9, specifically within the cpSeparateBufToContigBuf function located in tiffcp.c. This flaw arises from insufficient input validation when processing TIFF image files, creating a scenario where maliciously crafted TIFF content can trigger unauthorized memory access patterns. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. The impact of this vulnerability extends beyond simple denial of service, as it can potentially enable more sophisticated attack vectors depending on the execution environment and memory layout.
The technical exploitation of this vulnerability occurs when the tiffcp utility processes a malformed TIFF file that contains specially constructed data structures within the image buffer. During the cpSeparateBufToContigBuf function execution, the library fails to properly validate the size parameters of buffer allocations, leading to a situation where a crafted input can cause the program to write beyond the allocated heap memory region. This overflow condition manifests as a crash during image processing operations, effectively causing a denial of service condition that can be triggered remotely through file upload mechanisms or when the vulnerable library processes untrusted TIFF content. The vulnerability is particularly concerning because it operates at the library level, meaning any application that relies on LibTIFF for TIFF file processing becomes potentially vulnerable to this attack vector.
From an operational standpoint, this vulnerability poses significant risks to systems that process TIFF image files from untrusted sources, including web applications, document management systems, and image processing pipelines. Attackers can leverage this flaw to cause service disruption by forcing application crashes or to potentially execute arbitrary code if proper memory protection mechanisms are not in place. The attack surface is broad since TIFF format is widely used across various platforms and applications, making this vulnerability particularly dangerous in environments where automated processing of user-uploaded content occurs. The vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for privilege escalation or denial of service, and can be classified under T1499 for disruption of services through resource exhaustion or application crashes.
Mitigation strategies for CVE-2018-12900 should prioritize immediate patching of affected LibTIFF installations to version 4.0.10 or later, where the buffer overflow has been addressed through proper bounds checking and input validation mechanisms. Organizations should implement defensive programming practices including input sanitization, memory safety checks, and robust error handling when processing TIFF files. Network-based mitigations can include content filtering to prevent suspicious TIFF files from reaching vulnerable systems, while application-level protections should enforce strict resource limits and implement proper memory management practices. Security monitoring should focus on detecting unusual crash patterns or memory allocation behaviors in applications that utilize LibTIFF, as these could indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date third-party libraries and implementing comprehensive vulnerability management processes to prevent exploitation of known security flaws in widely-used software components.