CVE-2001-0973 in BSCW
Summary
by MITRE
BSCW groupware system 3.3 through 4.0.2 beta allows remote attackers to read or modify arbitrary files by uploading and extracting a tar file with a symlink into the data-bag space.
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Analysis
by VulDB Data Team • 06/09/2024
The BSCW groupware system vulnerability identified as CVE-2001-0973 represents a critical security flaw in versions 3.3 through 4.0.2 beta that enables remote attackers to gain unauthorized access to system files through a sophisticated attack vector involving symbolic link manipulation. This vulnerability exploits the system's inadequate input validation during file extraction processes, specifically when handling tar archives containing symbolic links. The flaw resides in the data-bag space management functionality where the system fails to properly sanitize or validate file paths during decompression operations, creating an opportunity for attackers to manipulate the extraction process and gain access to sensitive system resources.
The technical implementation of this vulnerability stems from the system's failure to properly handle symbolic links within tar archives during the extraction phase. When a malicious user uploads a specially crafted tar file containing symbolic links that point to system files outside the intended data-bag directory, the extraction process follows these links and places the targeted files in accessible locations within the data-bag space. This behavior directly violates security principles related to path traversal and access control, as the system does not properly validate or restrict the target destinations of extracted symbolic links. The vulnerability operates at the file system level and demonstrates a classic path traversal weakness that aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory.
From an operational perspective, this vulnerability presents significant risks to organizations utilizing BSCW groupware systems, as it allows attackers to both read arbitrary files from the system and modify critical data. The remote nature of the attack means that adversaries do not require local system access or physical presence to exploit this weakness, making it particularly dangerous in networked environments. Successful exploitation could lead to data breaches, system compromise, and unauthorized modification of groupware configuration files that control user access and system behavior. The impact extends beyond simple information disclosure to include potential privilege escalation and persistent access mechanisms that could allow attackers to maintain control over affected systems.
The attack methodology involves crafting a malicious tar archive containing symbolic links that point to sensitive system files such as configuration files, user credentials, or application data. When the BSCW system processes this archive for extraction, it follows the symbolic links and places the target files in the accessible data-bag space, making them available for unauthorized access. This technique leverages the principle of least privilege violation and demonstrates how improper input validation can create pathways for attackers to bypass normal access controls. The vulnerability also relates to ATT&CK technique T1059 which involves executing malicious code through compromised system processes, and T1078 which addresses valid accounts usage for persistence.
Organizations should implement immediate mitigations including disabling file upload functionality where possible, implementing strict input validation for all file operations, and ensuring proper path sanitization during archive extraction processes. System administrators should also consider implementing network segmentation to limit access to affected systems and deploy intrusion detection systems to monitor for suspicious file upload activities. The recommended approach includes updating to patched versions of BSCW groupware, implementing proper access controls for data-bag directories, and establishing monitoring procedures to detect unauthorized file system modifications. Additionally, regular security audits should verify that symbolic link handling processes properly validate and restrict file paths to prevent similar vulnerabilities from being exploited in other components of the system architecture.