CVE-2018-15209 in LibTIFF
Summary
by MITRE
ChopUpSingleUncompressedStrip in tif_dirread.c in LibTIFF 4.0.9 allows remote attackers to cause a denial of service (heap-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted TIFF file, as demonstrated by tiff2pdf.
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Analysis
by VulDB Data Team • 03/14/2020
The vulnerability identified as CVE-2018-15209 resides within the LibTIFF library version 4.0.9, specifically in the ChopUpSingleUncompressedStrip function located in the tif_dirread.c source file. This flaw represents a critical heap-based buffer overflow that can be exploited by remote attackers through the careful crafting of malicious TIFF image files. The vulnerability manifests when the library processes uncompressed strip data within TIFF metadata, creating a scenario where insufficient input validation leads to memory corruption. The affected function processes image data strips without adequate bounds checking, allowing attackers to manipulate the memory allocation process and trigger overflow conditions that can result in application crashes or more severe system instability. This issue specifically impacts applications that utilize LibTIFF for processing TIFF files, including the widely used tiff2pdf utility mentioned in the vulnerability description.
The technical execution of this vulnerability involves the manipulation of TIFF file structures to exploit improper memory handling during the decompression and processing of image strips. When a crafted TIFF file is processed, the ChopUpSingleUncompressedStrip function fails to properly validate the size parameters of uncompressed data strips, leading to attempts to write beyond allocated memory boundaries. This heap overflow condition can be triggered during the parsing of TIFF directory entries where strip offsets and byte counts are improperly validated. The vulnerability is particularly dangerous because it can be exploited through automated means, allowing remote attackers to craft malicious files that, when opened by vulnerable applications, will cause immediate system disruption. The buffer overflow occurs in the heap memory region, making it susceptible to both denial of service attacks and potential code execution scenarios depending on memory layout and exploitation conditions. The vulnerability falls under CWE-121 heap-based buffer overflow, which is classified as a fundamental memory safety issue that has been consistently identified as a critical threat in software security assessments.
The operational impact of CVE-2018-15209 extends beyond simple denial of service conditions to potentially enable more sophisticated attacks within environments where TIFF processing is prevalent. Applications that process untrusted TIFF input, including document management systems, image processing pipelines, and PDF conversion utilities, become vulnerable to this attack vector. The vulnerability can be exploited across multiple platforms where LibTIFF is implemented, including Unix-like systems, Windows environments, and various embedded systems that rely on TIFF format support. Organizations using affected software versions face significant risk of service disruption, particularly in environments where automated processing of user-uploaded images occurs. The attack surface is broadened by the widespread use of TIFF format in document workflows, medical imaging systems, and digital publishing platforms. Security incidents could result in unauthorized service interruption, data processing failures, and potential escalation to more severe exploitation scenarios, especially when combined with other vulnerabilities in the application stack. The vulnerability's impact is amplified by the fact that many applications automatically process TIFF files without extensive input sanitization, creating opportunities for exploitation through simple file uploads or network-based processing.
Mitigation strategies for CVE-2018-15209 primarily focus on immediate software updates and defensive programming practices. The most effective approach involves upgrading to LibTIFF version 4.0.10 or later, where the buffer overflow has been addressed through proper bounds checking and memory validation. System administrators should prioritize patching affected applications that utilize vulnerable LibTIFF versions, particularly those handling untrusted TIFF input. Network-based defenses can include implementing file type validation, content inspection, and sandboxing mechanisms to prevent malicious TIFF files from reaching vulnerable applications. Organizations should also consider implementing input validation layers that reject TIFF files with suspicious strip structures or unusual metadata parameters. The implementation of address space layout randomization and stack canaries can provide additional defense in depth against potential exploitation attempts. Security monitoring should include detection of unusual memory allocation patterns and application crashes related to TIFF processing. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for application execution, while the CWE classification of heap-based buffer overflow indicates the need for memory safety controls. Regular security assessments and vulnerability scanning should include checks for vulnerable LibTIFF installations, particularly in environments where TIFF processing is common. Organizations should also implement proper incident response procedures that account for potential exploitation of this vulnerability, including system isolation and forensic analysis capabilities.