CVE-2016-3624 in LibTIFF
Summary
by MITRE
The cvtClump function in the rgb2ycbcr tool in LibTIFF 4.0.6 and earlier allows remote attackers to cause a denial of service (out-of-bounds write) by setting the "-v" option to -1.
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Analysis
by VulDB Data Team • 09/21/2022
The cvtClump function in LibTIFF's rgb2ycbcr tool presents a critical vulnerability that enables remote attackers to execute denial of service attacks through out-of-bounds write operations. This vulnerability exists within LibTIFF version 4.0.6 and earlier releases, making it a persistent threat across multiple iterations of the library. The specific trigger occurs when attackers manipulate the "-v" command-line option to set its value to -1, which causes the function to process data in a manner that exceeds allocated memory boundaries. The rgb2ycbcr tool serves as a utility for converting RGB color space to YCbCr, but its implementation contains a fundamental flaw in input validation that allows malicious actors to exploit the memory management system.
The technical flaw manifests as an integer underflow condition that occurs when the cvtClump function processes negative values passed through the "-v" parameter. This vulnerability falls under the CWE-129 weakness category, which specifically addresses improper validation of array indices and buffer bounds. When the function receives a value of -1, it attempts to calculate array offsets using this negative value, resulting in memory locations that extend beyond the intended buffer boundaries. The out-of-bounds write operation can potentially overwrite adjacent memory segments, leading to unpredictable behavior including program crashes, memory corruption, or system instability. The vulnerability represents a classic example of insufficient input validation and improper bounds checking, which are fundamental security principles that should be enforced at all levels of software development.
The operational impact of this vulnerability extends beyond simple denial of service, as it creates potential pathways for more sophisticated attacks. Remote attackers can leverage this weakness to disrupt services by causing the rgb2ycbcr tool to crash, effectively rendering the tool unusable for legitimate operations. Systems that rely on LibTIFF for image processing tasks may experience cascading failures if the tool becomes unavailable, particularly in environments where automated image conversion processes depend on this functionality. The vulnerability is particularly concerning because it allows remote exploitation without requiring authentication, making it accessible to any attacker who can interact with the affected system. This characteristic aligns with ATT&CK technique T1499.004, which covers network denial of service attacks that target system availability through memory corruption vulnerabilities.
Mitigation strategies for this vulnerability require immediate patching of affected LibTIFF versions to 4.0.7 or later, where the input validation has been corrected to prevent negative values from being processed in the cvtClump function. System administrators should implement strict input validation at the application level, ensuring that all command-line parameters are properly sanitized before being passed to the rgb2ycbcr tool. Network segmentation and access controls can help limit exposure by restricting remote access to systems running vulnerable versions of the library. Additionally, monitoring systems should be configured to detect unusual command-line parameter usage patterns that might indicate exploitation attempts. Organizations should also consider implementing application whitelisting policies that restrict execution of untrusted binaries and ensure that only verified, patched versions of LibTIFF are deployed in production environments. The vulnerability demonstrates the critical importance of thorough input validation and proper bounds checking in preventing memory corruption attacks that can lead to system compromise or service disruption.