CVE-2005-3111 in backupninja
Summary
by MITRE
The handler code for backupninja 0.8 and earlier creates temporary files with predictable filenames, which allows local users to modify arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 06/10/2019
The vulnerability identified as CVE-2005-3111 affects backupninja version 0.8 and earlier, presenting a significant security risk through its handling of temporary files during backup operations. This flaw represents a classic case of insecure temporary file creation that can be exploited by local attackers to manipulate system files through symbolic link attacks. The vulnerability stems from the backupninja utility's failure to implement proper security measures when generating temporary files, creating predictable naming patterns that adversaries can anticipate and exploit.
The technical implementation of this vulnerability occurs within the backupninja handler code where temporary files are created without adequate randomization or secure naming conventions. When backupninja executes backup operations, it generates temporary files using predictable filenames that follow a discernible pattern, making it possible for local users to create symbolic links with the same names before the utility attempts to create them. This race condition allows attackers to redirect the backup utility's file operations to arbitrary locations, potentially enabling them to modify critical system files, inject malicious content, or escalate privileges within the system.
The operational impact of CVE-2005-3111 extends beyond simple file manipulation, as it can be leveraged for privilege escalation and persistent system compromise. Local users with minimal privileges can exploit this vulnerability to gain elevated access to the system, potentially allowing them to modify configuration files, inject malicious code into backup processes, or redirect backup data to locations under their control. This vulnerability directly maps to CWE-377, which addresses insecure temporary file creation, and represents a fundamental flaw in the security design of the backupninja utility's file handling mechanisms.
From an attack perspective, this vulnerability aligns with techniques documented in the MITRE ATT&CK framework under the T1059 and T1078 categories, where adversaries exploit local system weaknesses to maintain persistent access and escalate privileges. The predictable temporary file naming creates a window of opportunity for attackers to establish symbolic links before the legitimate backup process creates its temporary files, effectively allowing them to hijack the backup process and redirect it to malicious targets. The vulnerability's exploitation requires minimal privileges and can be automated, making it particularly dangerous in environments where backup operations are performed with elevated permissions.
Mitigation strategies for CVE-2005-3111 should focus on implementing secure temporary file creation practices that eliminate predictability in filename generation. System administrators should upgrade to backupninja versions that address this vulnerability through proper randomization of temporary file names and implementation of atomic file creation operations. Additionally, the system should enforce proper file permissions and ownership controls on backup directories to prevent unauthorized symbolic link creation. The solution should also include implementing proper input validation and using secure temporary file APIs that prevent race conditions, aligning with the security best practices outlined in NIST SP 800-123 and other secure coding guidelines. Organizations should also consider implementing monitoring and alerting mechanisms to detect unauthorized symbolic link creation in backup directories, providing an additional layer of defense against this type of attack.