CVE-2018-11684 in Liblouis
Summary
by MITRE
Liblouis 3.5.0 has a stack-based Buffer Overflow in the function includeFile in compileTranslationTable.c.
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Analysis
by VulDB Data Team • 03/21/2023
The vulnerability identified as CVE-2018-11684 represents a critical stack-based buffer overflow within Liblouis version 3.5.0, specifically within the includeFile function located in the compileTranslationTable.c source file. This issue arises during the compilation of translation tables where the library processes include directives that reference external files containing braille translation rules. The flaw manifests when the application fails to properly validate the length of data read from included files, leading to excessive data being written beyond the bounds of a statically allocated stack buffer. Such buffer overflow conditions create exploitable memory corruption scenarios that can potentially allow remote attackers to execute arbitrary code on affected systems.
The technical implementation of this vulnerability stems from improper input validation and memory management practices within the Liblouis translation table compilation process. When the includeFile function processes a file inclusion directive, it reads data from the referenced file without adequate bounds checking against the allocated buffer size. This allows maliciously crafted input files to overflow the stack buffer and overwrite adjacent memory locations including return addresses and stack canaries. The vulnerability is particularly concerning because Liblouis is widely used in accessibility software for braille translation, making it a target for attackers seeking to compromise systems running applications that depend on this library for text-to-braille conversion services.
The operational impact of CVE-2018-11684 extends beyond simple denial of service scenarios to encompass potential remote code execution capabilities. Systems utilizing Liblouis for processing translation tables, particularly those accepting user-supplied content or external braille files, become vulnerable to exploitation. This includes web applications, desktop software, and server-side processes that handle braille translation requests. Attackers could leverage this vulnerability to inject malicious code into the execution context of affected applications, potentially leading to complete system compromise. The vulnerability affects various platforms and applications that depend on Liblouis, including accessibility tools, educational software, and content management systems that support braille output generation.
Mitigation strategies for this vulnerability require immediate patching of affected Liblouis installations to version 3.6.0 or later, which contains the necessary fixes for the buffer overflow condition. System administrators should also implement input validation measures to restrict the types of files that can be processed through the includeFile function, particularly in environments where user-supplied content is accepted. Additionally, deploying runtime protections such as stack canaries, address space layout randomization, and data execution prevention mechanisms can help reduce the exploitability of this vulnerability. Organizations should conduct comprehensive vulnerability assessments to identify all systems utilizing affected versions of Liblouis and ensure proper patch management protocols are in place to prevent similar issues from arising in the future. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow and can be categorized under ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation may involve crafting malicious translation files to achieve code execution.