CVE-2006-2120 in libtiff
Summary
by MITRE
The TIFFToRGB function in libtiff before 3.8.1 allows remote attackers to cause a denial of service (crash) via a crafted TIFF image with Yr/Yg/Yb values that exceed the YCR/YCG/YCB values, which triggers an out-of-bounds read.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/18/2019
The vulnerability identified as CVE-2006-2120 resides within the libtiff library version 3.8.1 and earlier, specifically affecting the TIFFToRGB function. This flaw represents a classic buffer overflow condition that manifests as an out-of-bounds read when processing specially crafted TIFF image files. The vulnerability occurs when the Yr/Yg/Yb color values in a TIFF image exceed the valid YCR/YCG/YCB color space boundaries, creating a condition where the application attempts to access memory locations beyond the allocated buffer space. The issue stems from inadequate input validation and bounds checking within the color conversion routine that processes these specific color components. This vulnerability falls under the category of CWE-129, which describes improper validation of array indices, and specifically relates to CWE-787, out-of-bounds read, making it a critical concern for systems processing untrusted image data.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially lead to system instability and crash of applications relying on libtiff for image processing. When a maliciously crafted TIFF file is processed, the out-of-bounds read can cause memory corruption that results in application termination or system crashes. This makes the vulnerability particularly dangerous in environments where automated image processing occurs, such as web servers, image processing pipelines, or document management systems. The vulnerability can be exploited remotely through web applications that accept TIFF uploads or through email attachments that trigger image rendering. According to ATT&CK framework, this represents a privilege escalation vector through application exploitation, specifically targeting the execution of malicious code via buffer overflow techniques. The vulnerability affects systems running any software that utilizes libtiff versions prior to 3.8.1, including but not limited to web browsers, image viewers, document converters, and server applications processing TIFF format images.
Mitigation strategies for CVE-2006-2120 primarily focus on immediate software updates and patches to libtiff library versions 3.8.1 and later, which contain the necessary bounds checking and input validation fixes. System administrators should prioritize patching all affected applications and services that utilize libtiff, particularly those handling untrusted image data from external sources. Additionally, implementing proper input validation at multiple layers of the application stack can provide defense-in-depth protection. Network segmentation and access controls should be enforced to limit exposure of vulnerable systems to untrusted image data sources. Security monitoring should be enhanced to detect unusual application behavior or crashes that may indicate exploitation attempts. Organizations should also consider implementing sandboxing techniques for image processing operations and using automated vulnerability scanning tools to identify systems running vulnerable versions of libtiff. The fix implemented in libtiff 3.8.1 addresses the root cause by introducing proper bounds checking for the Yr/Yg/Yb values against the valid YCR/YCG/YCB color space limits, preventing the out-of-bounds memory access that previously caused the crashes. This vulnerability demonstrates the critical importance of maintaining up-to-date third-party libraries and implementing robust input validation practices in image processing applications.