CVE-2017-13739 in Liblouis
Summary
by MITRE
There is a heap-based buffer overflow that causes a more than two thousand bytes out-of-bounds write in Liblouis 3.2.0, triggered in the function resolveSubtable() in compileTranslationTable.c. It will lead to denial of service or remote code execution.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/11/2019
The heap-based buffer overflow vulnerability identified as CVE-2017-13739 represents a critical security flaw within the Liblouis braille translation library version 3.2.0. This vulnerability resides in the compileTranslationTable.c source file within the resolveSubtable() function, where improper bounds checking allows for arbitrary memory writes beyond allocated buffer boundaries. The flaw manifests as an out-of-bounds write operation that can exceed two thousand bytes, fundamentally compromising the memory integrity of applications utilizing this library. The vulnerability affects systems that process braille translation tables, particularly those implementing the Liblouis library for braille format conversion and translation services. The severity of this issue stems from the potential for both denial of service conditions and remote code execution, making it a significant concern for any system architecture relying on braille translation capabilities.
The technical exploitation of this vulnerability occurs when the resolveSubtable() function processes translation table data without adequate validation of input parameters or buffer size constraints. The heap-based nature of the overflow indicates that memory allocation occurs dynamically during runtime, and the buffer overflow specifically targets heap memory regions where translation table structures are stored. This type of vulnerability falls under CWE-121 heap-based buffer overflow classification, which represents a well-known and dangerous class of memory corruption vulnerabilities. When an attacker can manipulate the input data to the translation table processing function, they can overwrite adjacent heap memory locations, potentially corrupting critical data structures or even injecting executable code. The vulnerability's trigger mechanism specifically involves the compilation process of translation tables, where malformed or specially crafted table entries can cause the function to write beyond allocated memory boundaries.
The operational impact of CVE-2017-13739 extends beyond simple system crashes, presenting substantial risks to system availability and integrity across various computing environments. Applications that utilize Liblouis for braille translation services, including accessibility software, document processing systems, and educational platforms, become vulnerable to both service disruption and potential remote code execution attacks. The vulnerability's exploitation could result in complete system compromise when targets include web applications, server software, or any system that accepts braille translation table inputs from untrusted sources. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and control through remote code execution, while also supporting T1489 for denial of service attacks. The impact is particularly concerning in environments where automated translation table processing occurs, as the vulnerability can be triggered through simple input manipulation without requiring complex attack vectors.
Mitigation strategies for CVE-2017-13739 should prioritize immediate patching of affected Liblouis versions to remediate the buffer overflow condition in the resolveSubtable() function. System administrators must ensure that all applications utilizing Liblouis are updated to versions containing the fix, which typically involves implementing proper bounds checking and input validation mechanisms. Additional protective measures include implementing memory protection techniques such as stack canaries, address space layout randomization, and data execution prevention to reduce exploitability. Network segmentation and input filtering should be employed to prevent malicious translation table data from reaching vulnerable systems, while monitoring solutions should be deployed to detect anomalous behavior indicative of exploitation attempts. The vulnerability also highlights the importance of secure coding practices and regular security audits, particularly for libraries handling user-provided data. Organizations should consider implementing application whitelisting policies and restricting write access to translation table processing components to minimize potential attack surface exposure. Given the potential for remote code execution, comprehensive incident response procedures should be established to address possible exploitation attempts and system compromises.