CVE-2012-2088 in LibTIFF
Summary
by MITRE
Integer signedness error in the TIFFReadDirectory function in tif_dirread.c in libtiff 3.9.4 and earlier allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via a negative tile depth in a tiff image, which triggers an improper conversion between signed and unsigned types, leading to a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 02/03/2019
The vulnerability described in CVE-2012-2088 represents a critical integer signedness error within the libtiff library version 3.9.4 and earlier, specifically affecting the TIFFReadDirectory function in the tif_dirread.c source file. This flaw demonstrates a classic type conversion vulnerability that can be exploited remotely to cause system instability and potentially achieve arbitrary code execution. The issue stems from improper handling of signed and unsigned integer types during the processing of TIFF image files, creating a dangerous condition where a negative tile depth value can be interpreted incorrectly within the memory management system.
The technical flaw manifests when the TIFFReadDirectory function processes a malformed TIFF image containing a negative tile depth value. This negative value, when improperly converted from signed to unsigned types or vice versa, results in a heap-based buffer overflow condition. The vulnerability operates through a fundamental type confusion error where the application fails to properly validate the range of tile depth values before using them in memory allocation calculations. This type of error falls under the CWE-190 category of Integer Overflow or Wraparound, specifically manifesting as a signed integer overflow that leads to heap corruption. The improper conversion between signed and unsigned integer types creates a scenario where the calculated buffer size becomes significantly larger than intended, causing memory corruption when the application attempts to write data beyond the allocated heap space.
From an operational perspective, this vulnerability presents a severe risk to any system processing TIFF image files, particularly those exposed to untrusted input sources such as web applications, file upload systems, or document processing services. The remote exploitation capability means that attackers can trigger the vulnerability simply by uploading or accessing a maliciously crafted TIFF file, making it particularly dangerous in web environments where users might unknowingly interact with compromised images. The potential impact includes complete application crash leading to denial of service, which can be particularly devastating in mission-critical systems such as document management platforms, image processing servers, or content management systems. Additionally, the heap-based buffer overflow condition creates opportunities for more sophisticated exploitation techniques that could potentially lead to arbitrary code execution, allowing attackers to gain unauthorized control over affected systems.
The exploitation of this vulnerability aligns with several ATT&CK techniques including T1203, which involves legitimate programs being used for code execution, and T1499, which covers network denial of service attacks. The vulnerability also demonstrates characteristics of T1059, where adversaries may use command-line interfaces to execute malicious code. Organizations utilizing libtiff versions prior to 3.9.5 should prioritize immediate remediation through patching, as the vulnerability affects a core component of many image processing applications and systems. The mitigation strategy should include not only updating to patched versions of libtiff but also implementing input validation and sanitization measures for TIFF file processing, particularly in web-facing applications. Security teams should also consider deploying intrusion detection systems to monitor for exploitation attempts and implement network segmentation to limit the potential impact of successful attacks. The vulnerability underscores the importance of proper integer type handling and validation in security-critical code, as highlighted by industry best practices in secure coding standards and the need for comprehensive input validation across all system components processing external data.