CVE-2020-23172 in Kuba
Summary
by MITRE • 08/10/2021
A vulnerability in all versions of Kuba allows attackers to overwrite arbitrary files in arbitrary directories with crafted Zip files due to improper validation of file paths in .zip archives.
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Analysis
by VulDB Data Team • 08/15/2021
The vulnerability identified as CVE-2020-23172 represents a critical path traversal flaw within the Kuba software ecosystem that enables remote attackers to execute arbitrary file overwrites through maliciously crafted zip archives. This weakness exists in all versions of the affected software and stems from inadequate validation mechanisms that fail to properly sanitize file paths contained within compressed archive structures. The vulnerability operates at the core of file handling operations where archive extraction processes do not sufficiently verify or filter the absolute or relative paths specified within zip file entries, creating an opportunity for attackers to manipulate the target directory structure during decompression operations.
This security flaw directly maps to CWE-22, which defines path traversal vulnerabilities where insufficient input validation allows attackers to access files or directories outside the intended scope. The vulnerability exploits the fundamental trust placed in archive contents without proper sanitization of path components, particularly when processing zip files that may contain entries with ../ sequences or absolute paths. Attackers can craft zip archives containing entries with malicious path specifications that, when extracted, overwrite files in arbitrary directories on the target system. The impact extends beyond simple file corruption as it can lead to privilege escalation, code execution, and complete system compromise when combined with other vulnerabilities or attack vectors.
The operational impact of CVE-2020-23172 is severe and multifaceted across various deployment scenarios where Kuba software processes untrusted zip archives. System administrators may encounter unauthorized file modifications in critical system directories, application directories, or user data storage areas. The vulnerability can be exploited through multiple attack surfaces including web applications that accept file uploads, automated processing systems, and backup restoration procedures that utilize zip file formats. When combined with other techniques such as those described in the MITRE ATT&CK framework under T1059 for command and script injection, this vulnerability can facilitate more sophisticated attack chains where initial file overwrites enable subsequent privilege escalation or persistence mechanisms.
Mitigation strategies for CVE-2020-23172 require immediate implementation of robust input validation and sanitization procedures within all zip archive processing components. Organizations should implement comprehensive path validation that strips or rejects any path components containing parent directory references, absolute paths, or other potentially malicious path sequences. The solution must incorporate proper directory traversal prevention mechanisms that enforce strict containment policies for archive extraction operations, ensuring that all extracted files are confined to predetermined safe directories. Additionally, system administrators should consider implementing principle of least privilege controls, restricting write permissions for archive processing directories, and deploying automated monitoring systems to detect unauthorized file modifications. The remediation approach should align with security best practices outlined in NIST SP 800-160 and ISO/IEC 27001 standards for secure software development and vulnerability management processes.