CVE-2015-8919 in libarchive
Summary
by MITRE
The lha_read_file_extended_header function in archive_read_support_format_lha.c in libarchive before 3.2.0 allows remote attackers to cause a denial of service (out-of-bounds heap) via a crafted (1) lzh or (2) lha file.
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Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2015-8919 represents a critical heap-based out-of-bounds read flaw within the libarchive library's LHA format handling functionality. This issue specifically affects the lha_read_file_extended_header function located in archive_read_support_format_lha.c, which processes lzh and lha archive files. The vulnerability exists in libarchive versions prior to 3.2.0, making a substantial portion of systems using older library versions susceptible to exploitation. The flaw enables remote attackers to craft malicious archive files that trigger memory access violations when the library attempts to parse extended headers in LHA format archives.
The technical nature of this vulnerability stems from inadequate input validation and bounds checking within the archive parsing logic. When processing crafted lzh or lha files, the lha_read_file_extended_header function fails to properly validate the size and structure of extended header data, leading to heap memory access beyond allocated boundaries. This out-of-bounds heap access can result in unpredictable program behavior including crashes, memory corruption, or potential exploitation for more severe attacks. The vulnerability manifests during the archive extraction or parsing process when the library encounters malformed extended header information in the archive file structure. The flaw operates at the application level where legitimate archive processing routines are leveraged to execute malicious code through carefully constructed input data.
From an operational impact perspective, this vulnerability creates significant risk for systems that process untrusted archive files, particularly those handling user-uploaded content or downloading archives from external sources. The denial of service aspect means that systems could become unavailable or crash when processing maliciously crafted LHA archives, potentially disrupting services for legitimate users. The vulnerability affects any application or system that utilizes libarchive for LHA format processing, including file managers, backup utilities, web applications, and content delivery systems. Organizations relying on older libarchive versions may experience service interruptions or require emergency patching to maintain system availability. The remote exploitation capability means that attackers can trigger this vulnerability without local access, making it particularly dangerous for web-facing applications that process archive files.
Mitigation strategies for CVE-2015-8919 primarily focus on upgrading to libarchive version 3.2.0 or later, where the vulnerability has been addressed through improved input validation and bounds checking. System administrators should prioritize patching affected systems, particularly those handling untrusted archive files or operating in multi-user environments. Additionally, implementing proper input sanitization at application layers can provide defense-in-depth measures, though the primary fix must occur at the library level. Network segmentation and access controls can help limit exposure by restricting access to systems that process archive files, while monitoring systems should be configured to detect unusual patterns in archive processing that might indicate exploitation attempts. Organizations should also consider implementing automated patch management processes to ensure timely updates across their infrastructure. The vulnerability aligns with CWE-125 Out-of-bounds Read and follows ATT&CK techniques related to privilege escalation through software vulnerabilities, though the immediate impact is primarily denial of service rather than direct execution.