CVE-2017-14502 in libarchive
Summary
by MITRE
read_header in archive_read_support_format_rar.c in libarchive 3.3.2 suffers from an off-by-one error for UTF-16 names in RAR archives, leading to an out-of-bounds read in archive_read_format_rar_read_header.
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Analysis
by VulDB Data Team • 12/29/2022
The vulnerability identified as CVE-2017-14502 resides within the libarchive library version 3.3.2, specifically in the archive_read_support_format_rar.c component responsible for processing RAR archive files. This flaw manifests as an off-by-one error during the handling of UTF-16 encoded filenames within RAR archives, creating a critical memory access violation that can be exploited by malicious actors. The issue occurs during the read_header function execution when processing archive_read_format_rar_read_header operations, where the library fails to properly validate buffer boundaries when interpreting Unicode filenames.
The technical implementation of this vulnerability stems from improper boundary checking in the UTF-16 name parsing logic. When libarchive encounters RAR archives containing UTF-16 encoded filenames, the off-by-one error causes the software to access memory locations beyond the allocated buffer boundaries. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of the length of input data, and more broadly relates to CWE-125, which covers out-of-bounds read conditions. The flaw represents a classic buffer overflow scenario where the program attempts to read beyond the valid memory limits of a data structure.
The operational impact of CVE-2017-14502 extends beyond simple memory corruption, as it can lead to arbitrary code execution or application crashes when processing maliciously crafted RAR archives. Attackers can exploit this vulnerability by creating specially crafted RAR files containing malformed UTF-16 encoded filenames that trigger the out-of-bounds read condition. This vulnerability is particularly dangerous because it can be exploited through common archive processing operations such as file listing, extraction, or validation functions. The attack surface includes any application or system that relies on libarchive for RAR archive processing, including web applications, file servers, and security scanning tools that handle user-uploaded archives.
From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1059.007, which involves the execution of malicious code through legitimate system processes, and T1203, which covers legitimate user execution. The vulnerability can be leveraged in supply chain attacks where malicious actors inject compromised RAR archives into software distribution channels, or in phishing campaigns where users unknowingly trigger the exploit through archive extraction. Mitigation strategies should include immediate patching of libarchive to version 3.3.3 or later, which contains the necessary boundary checks to prevent the out-of-bounds read condition. Additionally, organizations should implement strict archive validation procedures, employ sandboxing techniques for archive processing, and consider network-based intrusion detection systems that can identify suspicious archive content patterns. The vulnerability demonstrates the critical importance of proper input validation in archive processing libraries and highlights the need for comprehensive security testing of file format parsers against malformed inputs.