CVE-2021-33211 in HTTP Commander
Summary
by MITRE • 07/15/2021
A Directory Traversal vulnerability in the Unzip feature in Elements-IT HTTP Commander 5.3.3 allows remote authenticated users to write files to arbitrary directories via relative paths in ZIP archives.
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Analysis
by VulDB Data Team • 07/18/2021
The vulnerability identified as CVE-2021-33211 represents a critical directory traversal flaw within the Elements-IT HTTP Commander 5.3.3 web-based file manager application. This security weakness specifically affects the unzip functionality, creating a pathway for malicious actors to manipulate file extraction processes and potentially compromise the underlying system. The vulnerability exists in the application's handling of relative paths during ZIP archive decompression, allowing attackers to escape the intended extraction directory and write files to arbitrary locations on the server filesystem. This issue impacts organizations that rely on HTTP Commander for file management operations, particularly those with web-facing applications that process user-uploaded archives.
The technical implementation of this vulnerability stems from inadequate input validation and path sanitization within the unzip feature's code execution flow. When processing ZIP archives, the application fails to properly validate or sanitize the file paths contained within the archive, allowing relative path sequences such as ../ or ..\ to pass through unfiltered. This weakness aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw operates by accepting user-supplied paths from ZIP archives without proper canonicalization or directory validation, enabling attackers to specify absolute or relative paths that bypass intended security boundaries during file extraction operations.
From an operational perspective, this vulnerability creates significant risk for organizations using HTTP Commander 5.3.3, particularly those with authenticated access controls. Remote authenticated users can exploit this weakness to write malicious files to critical system directories, potentially leading to arbitrary code execution, privilege escalation, or data corruption. The attack vector requires only authentication to the web application, making it particularly dangerous in environments where user access is not strictly controlled or monitored. Attackers could leverage this vulnerability to deploy web shells, modify configuration files, or inject malicious code into the application's execution environment, potentially compromising the entire web server infrastructure. The impact extends beyond simple file manipulation as it could enable attackers to escalate privileges and gain deeper system access.
Mitigation strategies for CVE-2021-33211 should prioritize immediate remediation through vendor-provided patches or updates. Organizations should implement strict input validation for all file paths during archive extraction processes, ensuring that relative path sequences are properly sanitized or rejected. The implementation of proper directory traversal prevention mechanisms, including canonical path resolution and directory boundary enforcement, should be enforced within the application's file handling code. Additionally, system administrators should consider implementing network-level controls such as web application firewalls that can detect and block suspicious path traversal patterns in file upload operations. Security monitoring should be enhanced to detect unusual file creation patterns or access attempts to sensitive system directories. Organizations should also review their access control policies to ensure that only authorized users have the ability to upload and extract archives, implementing principle of least privilege controls. This vulnerability demonstrates the importance of secure coding practices and input validation in web applications, particularly those handling user-supplied data through file processing features, aligning with ATT&CK technique T1059.007 for execution through web shells and T1078 for valid accounts and privilege escalation.