CVE-2015-3205 in libmimedir
Summary
by MITRE
libmimedir allows remote attackers to execute arbitrary code via a VCF file with two NULL bytes at the end of the file, related to "free" function calls in the "lexer's memory clean-up procedure."
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/02/2024
The vulnerability identified as CVE-2015-3205 resides within the libmimedir library, a component commonly used for parsing and processing MIME directory files including vCard format data. This flaw represents a classic buffer overflow condition that occurs during the parsing of malformed vCard files, specifically when the file contains two trailing NULL bytes. The vulnerability stems from improper memory management within the library's lexer component, which is responsible for tokenizing and processing the vCard data structure. When the parser encounters a vCard file with these specific characteristics, it triggers a memory cleanup routine that contains a critical flaw in how it handles the freeing of allocated memory blocks.
The technical execution of this vulnerability occurs through a memory corruption attack that exploits the improper handling of memory deallocation during the lexer's cleanup phase. When the parser processes a vCard file ending with two NULL bytes, the memory management functions within the lexer's cleanup procedure fail to properly account for the memory state, leading to a situation where freed memory blocks are either accessed again or corrupted during subsequent operations. This memory corruption directly translates to arbitrary code execution capabilities for remote attackers who can craft malicious vCard files to exploit this condition. The vulnerability specifically affects the "free" function calls within the memory cleanup procedure, making it a direct memory management flaw that aligns with CWE-415 and CWE-416 categories.
The operational impact of this vulnerability extends significantly beyond simple code execution, as it provides attackers with complete control over the affected system when the vulnerable library is used to process user-supplied vCard data. This typically occurs in email clients, contact management applications, and other software that handles vCard file processing, making the attack surface quite broad. The remote exploitation capability means that attackers can deliver malicious vCard files through email attachments, web-based contact import features, or any mechanism that processes vCard data through the vulnerable library. This vulnerability directly maps to attack techniques described in the ATT&CK framework under initial access and execution phases, particularly leveraging malicious file attachments and privilege escalation through code execution.
Mitigation strategies for this vulnerability require immediate patching of the libmimedir library to correct the memory management issues in the lexer's cleanup procedure. Organizations should prioritize updating all systems that utilize this library, particularly email servers, contact management applications, and any software that handles vCard file processing. Additional defensive measures include implementing strict file validation for vCard inputs, employing sandboxing techniques for file processing, and deploying network-based intrusion detection systems to monitor for suspicious vCard file patterns. The vulnerability's classification as a memory corruption issue makes it particularly dangerous, as it can be exploited without requiring user interaction beyond the simple act of processing a malicious file, making automated exploitation highly likely and increasing the overall risk to affected systems.