CVE-2018-11434 in Libmobi
Summary
by MITRE
The buffer_fill64 function in compression.c in Libmobi 0.3 allows remote attackers to cause information disclosure (heap-based buffer over-read) via a crafted mobi file.
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Analysis
by VulDB Data Team • 02/09/2020
The vulnerability identified as CVE-2018-11434 resides within the Libmobi 0.3 library, specifically in the buffer_fill64 function located in compression.c. This flaw represents a heap-based buffer over-read condition that can be exploited by remote attackers through the careful crafting of mobi files. The Libmobi library serves as a crucial component for processing mobi format files, which are commonly used for e-book distribution and reading applications across various platforms. The vulnerability manifests when the library processes malformed input data that triggers an improper buffer handling mechanism, leading to memory access violations that expose sensitive information from adjacent memory regions.
The technical implementation of this vulnerability stems from inadequate bounds checking within the buffer_fill64 function, which is responsible for managing data compression operations during mobi file processing. When the function encounters specially crafted mobi files, it fails to properly validate the size parameters of buffer operations, resulting in a situation where the program reads beyond the allocated memory boundaries. This heap-based buffer over-read allows attackers to access memory contents that should remain protected, potentially exposing sensitive data such as cryptographic keys, user credentials, or application state information. The vulnerability is classified under CWE-125 as an out-of-bounds read, which falls within the broader category of memory safety issues that have become increasingly prevalent in software systems.
The operational impact of CVE-2018-11434 extends beyond simple information disclosure, as it creates opportunities for more sophisticated attacks that could lead to system compromise. Remote attackers can leverage this vulnerability to extract confidential information from memory segments, potentially including session tokens, database connection details, or other sensitive application data. The attack vector is particularly concerning because it requires no local privileges or user interaction beyond accessing a maliciously crafted mobi file, making it suitable for automated exploitation across multiple systems. This vulnerability affects any application or system that utilizes Libmobi 0.3 for processing mobi format files, including e-book readers, content management systems, and mobile applications that support this file format. The exposure of sensitive memory contents through heap-based buffer over-reads aligns with techniques documented in the ATT&CK framework under the information gathering and credential access phases, where adversaries seek to extract valuable data from compromised systems.
Mitigation strategies for this vulnerability should focus on immediate library updates and input validation measures. The most effective approach involves upgrading to a patched version of Libmobi that addresses the buffer over-read condition in the buffer_fill64 function. Security practitioners should also implement strict input validation procedures that verify mobi file integrity before processing, including size parameter checking and memory boundary enforcement. Additional protective measures include deploying application sandboxing techniques, implementing memory protection mechanisms such as stack canaries, and utilizing address space layout randomization to complicate exploitation attempts. Organizations should conduct comprehensive vulnerability assessments to identify all systems utilizing affected versions of Libmobi and establish monitoring procedures to detect potential exploitation attempts. The remediation process should also include code reviews focused on buffer management practices and adherence to secure coding standards that prevent similar vulnerabilities from emerging in future implementations.