CVE-2017-11613 in LibTIFF
Summary
by MITRE
In LibTIFF 4.0.8, there is a denial of service vulnerability in the TIFFOpen function. A crafted input will lead to a denial of service attack. During the TIFFOpen process, td_imagelength is not checked. The value of td_imagelength can be directly controlled by an input file. In the ChopUpSingleUncompressedStrip function, the _TIFFCheckMalloc function is called based on td_imagelength. If we set the value of td_imagelength close to the amount of system memory, it will hang the system or trigger the OOM killer.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-11613 represents a critical denial of service weakness within the LibTIFF library version 4.0.8, specifically affecting the TIFFOpen function. This flaw operates through a sophisticated manipulation of image file parameters that can cause system instability and resource exhaustion. The vulnerability stems from insufficient validation of the td_imagelength field during the TIFF file parsing process, creating an exploitable condition where malicious input can directly influence system behavior. The flaw manifests when an attacker crafts a specially formatted TIFF file that sets td_imagelength to an excessive value, effectively bypassing normal input validation mechanisms that should constrain file parameter sizes.
The technical execution of this vulnerability occurs through the ChopUpSingleUncompressedStrip function which invokes the _TIFFCheckMalloc function based on the controlled td_imagelength value. This creates a direct path for memory allocation manipulation where the system attempts to allocate memory proportional to the attacker-controlled parameter. When td_imagelength is set to approach system memory limits, the memory allocation request becomes so large that it either causes the system to hang indefinitely or triggers the Linux Out-Of-Memory killer process to terminate the application. The vulnerability operates at the intersection of memory management and input validation, where the lack of proper bounds checking allows arbitrary memory consumption that can exhaust system resources.
This vulnerability impacts a wide range of systems that utilize LibTIFF for image processing, including web servers, image processing applications, and document management systems. The operational impact extends beyond simple service disruption to potentially system-wide instability, particularly in environments where memory resources are constrained or where multiple concurrent processes are running. The vulnerability's exploitability is relatively straightforward since it requires only the creation of a malformed TIFF file, making it accessible to attackers with minimal technical expertise. The lack of input sanitization during the TIFFOpen process creates an attack surface that can be leveraged in automated systems or web applications that process user-uploaded images without proper validation.
From a cybersecurity perspective, this vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and can be categorized under ATT&CK technique T1499.001 for network denial of service attacks. The vulnerability demonstrates poor defensive programming practices where the system fails to implement adequate input validation and resource allocation limits. Mitigation strategies should focus on implementing strict bounds checking for td_imagelength parameters, establishing maximum memory allocation limits, and deploying input validation layers that prevent maliciously large values from being processed. Additionally, system administrators should consider implementing memory limits and process isolation measures to contain potential exploitation effects. The recommended approach includes upgrading to patched versions of LibTIFF, implementing proper input sanitization, and deploying network monitoring to detect unusual memory allocation patterns that may indicate exploitation attempts.