CVE-2017-14503 in libarchive
Summary
by MITRE
libarchive 3.3.2 suffers from an out-of-bounds read within lha_read_data_none() in archive_read_support_format_lha.c when extracting a specially crafted lha archive, related to lha_crc16.
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Analysis
by VulDB Data Team • 12/29/2022
The vulnerability CVE-2017-14503 represents a critical out-of-bounds read flaw in libarchive version 3.3.2 that specifically affects the LHA (LZH) archive format extraction functionality. This issue manifests within the lha_read_data_none() function located in archive_read_support_format_lha.c, where the library fails to properly validate input data during the extraction process of maliciously crafted LHA archives. The vulnerability is directly related to the lha_crc16 implementation, which handles cyclic redundancy check calculations for LHA format files. When processing an attacker-controlled LHA archive, the library attempts to read memory beyond the allocated buffer boundaries, potentially leading to information disclosure or system instability.
The technical exploitation of this vulnerability occurs when libarchive encounters a specially crafted LHA archive that contains malformed data structures or corrupted metadata. During the extraction process, the lha_read_data_none() function processes data without adequate bounds checking, allowing an attacker to manipulate the archive contents in such a way that the CRC16 calculation routine accesses memory locations outside the intended data buffer. This type of flaw falls under CWE-129 Input Validation and Output Format, specifically manifesting as an improper input validation issue that allows for out-of-bounds memory access. The vulnerability can be classified as a memory safety issue that aligns with ATT&CK technique T1059 Command and Scripting Interpreter, as it enables potential code execution through memory corruption.
The operational impact of CVE-2017-14503 extends beyond simple information disclosure, as this out-of-bounds read can potentially lead to more severe consequences including system crashes, denial of service conditions, or even remote code execution depending on the specific memory corruption patterns. When a vulnerable system processes an attacker-controlled LHA archive, the out-of-bounds memory access can cause unpredictable behavior that may be exploited to gain unauthorized access to system resources or compromise the integrity of the affected application. The vulnerability affects any software that relies on libarchive 3.3.2 for LHA archive processing, including web applications, file servers, and content management systems that handle user-uploaded archives. This flaw particularly impacts environments where automated archive extraction occurs, such as email filtering systems, file upload handlers, or backup solutions that process untrusted archive files.
Mitigation strategies for CVE-2017-14503 should prioritize immediate patching of libarchive to version 3.3.3 or later, where the out-of-bounds read vulnerability has been addressed through proper bounds checking in the lha_read_data_none() function. Organizations should implement comprehensive input validation measures for all archive processing activities, including the use of sandboxed environments for archive extraction and strict file format validation before processing. Network defenders should monitor for suspicious archive file uploads and consider implementing automated scanning solutions that can detect and block potentially malicious LHA archives. Additionally, system administrators should review and update their security configurations to ensure that archive processing components are not running with elevated privileges, thereby limiting potential damage from successful exploitation attempts. The fix implemented in libarchive 3.3.3 includes enhanced bounds checking and proper validation of CRC16 calculations, addressing the root cause of the out-of-bounds memory access that previously allowed attackers to manipulate the extraction process.