CVE-2016-4302 in libarchive
Summary
by MITRE
Heap-based buffer overflow in the parse_codes function in archive_read_support_format_rar.c in libarchive before 3.2.1 allows remote attackers to execute arbitrary code via a RAR file with a zero-sized dictionary.
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Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2016-4302 represents a critical heap-based buffer overflow within the libarchive library, specifically affecting the parse_codes function in the archive_read_support_format_rar.c file. This flaw exists in versions prior to 3.2.1 and poses a significant security risk to systems that process RAR archive files. The vulnerability manifests when the library encounters a RAR file containing a zero-sized dictionary, which triggers improper memory handling during the parsing process. The heap-based nature of this overflow indicates that the vulnerability occurs in dynamically allocated memory regions, making it particularly dangerous as it can lead to arbitrary code execution with the privileges of the affected application.
The technical implementation of this vulnerability stems from inadequate bounds checking within the parse_codes function, which is responsible for processing RAR archive formats. When the function processes a RAR file with a zero-sized dictionary, it fails to properly validate the dictionary size before attempting to allocate or access memory buffers. This failure creates a condition where an attacker can craft a malicious RAR file that, when processed by an application using vulnerable libarchive versions, causes memory corruption. The zero-sized dictionary serves as a trigger that bypasses normal validation checks, allowing the attacker to manipulate memory layout and potentially overwrite critical program structures. This type of vulnerability falls under CWE-121 heap-based buffer overflow, which is classified as a serious weakness in memory management and data validation practices.
The operational impact of CVE-2016-4302 extends across numerous systems and applications that rely on libarchive for archive processing, including web servers, file processing applications, and security tools. Attackers can exploit this vulnerability remotely by delivering malicious RAR files through various attack vectors such as email attachments, web downloads, or file sharing platforms. The arbitrary code execution capability provides attackers with complete control over the affected system, potentially leading to data theft, system compromise, or further lateral movement within network environments. This vulnerability is particularly concerning because RAR files are commonly used for software distribution and file compression, making the attack surface broad and accessible. The exploitation aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would enable attackers to execute arbitrary commands within the compromised system.
Mitigation strategies for CVE-2016-4302 primarily focus on upgrading to libarchive version 3.2.1 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should prioritize updating all applications that depend on libarchive, particularly those handling untrusted archive files. Additional protective measures include implementing strict file validation policies that scan for suspicious archive file characteristics before processing, deploying network-based intrusion detection systems to monitor for known attack patterns, and applying application whitelisting controls to restrict execution of untrusted archive processing utilities. Organizations should also consider implementing sandboxing mechanisms for archive processing to limit potential damage from successful exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory management in security-critical libraries, reinforcing the need for regular security updates and comprehensive vulnerability management programs.