CVE-2017-13740 in Liblouis
Summary
by MITRE
There is a stack-based buffer overflow in Liblouis 3.2.0, triggered in the function parseChars() in compileTranslationTable.c, that will lead to denial of service or possibly unspecified other impact.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-13740 represents a critical stack-based buffer overflow within the Liblouis braille translation library version 3.2.0. This flaw exists in the parseChars() function located within the compileTranslationTable.c source file, making it a fundamental security issue that affects the library's ability to process braille translation tables properly. The Liblouis library serves as a core component for braille text processing and translation across multiple platforms, including operating systems, accessibility tools, and assistive technologies that rely on proper braille rendering capabilities.
The technical implementation of this vulnerability stems from inadequate input validation and boundary checking within the parseChars() function. When the library processes translation table data containing malformed or excessively long character sequences, the function fails to properly validate the size of input buffers before copying data onto the stack. This lack of proper bounds checking creates an exploitable condition where an attacker can craft malicious input that exceeds the allocated stack buffer space, causing a buffer overflow that can overwrite adjacent memory locations. The vulnerability manifests as a classic stack-based buffer overflow scenario that falls under CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient boundary checks allow data to overwrite adjacent stack memory.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, potentially enabling more sophisticated attacks depending on the execution environment and memory layout. While the primary effect results in application crashes and denial of service conditions, the nature of stack-based buffer overflows creates opportunities for more severe consequences including arbitrary code execution, particularly when the vulnerable system employs non-executable stack protections or when combined with other exploitation techniques. The vulnerability affects any application or system that utilizes Liblouis 3.2.0 for braille translation processing, which includes accessibility software, operating system components, and various assistive technologies that depend on proper braille rendering capabilities. This makes the impact widespread across the accessibility technology ecosystem and potentially exposes numerous endpoints to potential exploitation.
Mitigation strategies for this vulnerability require immediate patching of the Liblouis library to version 3.3.0 or later, which contains the necessary fixes for the buffer overflow condition. System administrators and software vendors should prioritize updating all affected installations and implementations that utilize the vulnerable library version. Additionally, implementing proper input validation measures and boundary checks within applications that interface with Liblouis can provide additional defense-in-depth protections. The remediation approach aligns with standard ATT&CK framework techniques for vulnerability management and software supply chain security, emphasizing the importance of maintaining up-to-date libraries and implementing proper software hygiene practices. Organizations should also consider implementing runtime protections such as stack canaries, address space layout randomization, and non-executable stack protections to reduce the potential impact of similar vulnerabilities that may exist in other components of their software ecosystem.