CVE-2017-2158 in Lhaplus
Summary
by MITRE
Improper verification when expanding ZIP64 archives in Lhaplus versions 1.73 and earlier may lead to unintended contents to be extracted from a specially crafted ZIP64 archive.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/30/2021
The vulnerability identified as CVE-2017-2158 represents a critical flaw in the Lhaplus software library's handling of ZIP64 archive expansion processes. This issue affects versions 1.73 and earlier, where the software fails to properly validate the structure and contents of ZIP64 archives during extraction operations. The improper verification mechanism creates a pathway for maliciously crafted archives to bypass normal extraction safeguards, potentially leading to unauthorized file placement or execution within the target system environment.
The technical root cause of this vulnerability lies in the insufficient validation of archive metadata and file paths during ZIP64 expansion. When processing ZIP64 archives, the software should rigorously verify that file paths do not contain malicious constructs such as directory traversal sequences or invalid path references. However, the flawed implementation allows certain specially crafted archive entries to pass validation checks that should have prevented their extraction. This weakness specifically manifests when dealing with the extended format capabilities of ZIP64 archives, which support larger file sizes and more complex directory structures than traditional ZIP archives.
From an operational perspective, this vulnerability presents significant security risks to systems that rely on Lhaplus for archive processing. An attacker could craft a malicious ZIP64 archive containing files with unexpected paths or content that would be extracted to unintended locations on the target system. The impact extends beyond simple file placement, as the vulnerability could potentially enable privilege escalation or code execution if the extracted files are executable or if they overwrite critical system components. The vulnerability's exploitation requires the target system to process the malicious archive through Lhaplus functionality, making it particularly concerning for applications that automatically extract or process user-provided archives without additional validation layers.
The vulnerability maps to CWE-22, which addresses improper limitation of a pathname to a restricted directory, commonly known as directory traversal attacks. This classification reflects the core issue where the software fails to properly restrict file paths during archive extraction. Additionally, the weakness aligns with ATT&CK technique T1059.007, which covers the execution of malicious code through archive extraction processes. Organizations should implement immediate mitigations including upgrading to Lhaplus versions that address this vulnerability, implementing additional validation layers for archive processing, and conducting security reviews of systems that utilize Lhaplus for archive handling. The remediation process should also include network segmentation and access controls to limit the potential impact of successful exploitation attempts.