CVE-2005-1064 in Filesystem Snapshot Utility
Summary
by MITRE
The copy_symlink function in rsnapshot 1.2.0 and 1.1.x before 1.1.7 changes the ownership of files that a symlink points to rather than the symlink itself, which allows local users to obtain access to arbitrary files.
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Analysis
by VulDB Data Team • 06/07/2019
The vulnerability identified as CVE-2005-1064 represents a critical privilege escalation flaw within the rsnapshot backup utility version 1.2.0 and 1.1.x prior to 1.1.7. This issue stems from a fundamental mismanagement of file permissions and ownership during symbolic link handling operations. The rsnapshot utility, designed for creating incremental backups of filesystems, contains a flaw in its copy_symlink function that directly impacts how it processes symbolic links during backup operations. When rsnapshot encounters a symbolic link during the backup process, the flawed implementation incorrectly transfers ownership of the target file that the symlink points to, rather than properly managing the symlink itself. This misbehavior creates a significant security gap that local attackers can exploit to gain unauthorized access to files they would normally not have permission to access.
The technical root cause of this vulnerability lies in the improper handling of file ownership transfer mechanisms within the rsnapshot codebase. Specifically, when the copy_symlink function processes symbolic links, it fails to distinguish between the symlink object itself and the file it references. This confusion results in the system applying ownership changes to the target file instead of the symbolic link, effectively allowing attackers to manipulate file permissions in unintended ways. The flaw operates at the filesystem level where the backup utility's permission handling logic does not properly account for the special nature of symbolic links and their relationship to target files. According to CWE-276, this vulnerability maps to improper file permissions, while also relating to CWE-256 which addresses improper privilege management in file operations. The operational impact of this flaw extends beyond simple file access, as it enables attackers to bypass normal access controls and potentially escalate privileges to access sensitive system files, configuration data, or user information.
The security implications of CVE-2005-1064 are particularly severe in environments where rsnapshot is used for system backups and where local user accounts have access to the backup utility. Attackers can leverage this vulnerability to manipulate backup operations and gain access to files that should remain protected, potentially leading to data breaches, privilege escalation, or system compromise. The vulnerability specifically affects systems where rsnapshot is configured to run with elevated privileges or where backup operations involve files owned by different users or system accounts. This flaw creates a pathway for attackers to access arbitrary files through the backup process, which could include sensitive configuration files, user credentials, or system binaries. The impact is further amplified when considering that rsnapshot is commonly used in enterprise environments for regular backup operations, making this vulnerability particularly dangerous for organizations that rely on automated backup systems.
Mitigation strategies for CVE-2005-1064 require immediate patching of affected rsnapshot versions to the corrected 1.1.7 release or later, which properly addresses the symlink ownership handling. System administrators should also implement additional security controls such as restricting local user access to rsnapshot operations, ensuring that backup processes run with minimal necessary privileges, and monitoring backup operations for unusual file access patterns. Organizations should consider implementing proper access controls and privilege separation to prevent local users from manipulating backup processes. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the T1068 privilege escalation tactic where attackers exploit software vulnerabilities to gain elevated system privileges. Security teams should also conduct regular vulnerability assessments of backup utilities and ensure that all system components are kept up to date with security patches. Additionally, implementing proper logging and monitoring of backup operations can help detect suspicious activities that might indicate exploitation attempts of this vulnerability.