CVE-2000-0537 in BRU Backup
Summary
by MITRE
BRU backup software allows local users to append data to arbitrary files by specifying an alternate configuration file with the BRUEXECLOG environmental variable.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability identified as CVE-2000-0537 resides within BRU backup software, a data protection tool commonly used in enterprise environments for system backups and recovery operations. This flaw represents a classic path traversal and file manipulation vulnerability that exploits the software's handling of environmental variables during backup execution processes. The vulnerability specifically affects local users who possess the ability to execute programs on the target system, making it particularly concerning in environments where user privileges are not strictly controlled or where users have access to backup utilities.
The technical exploitation mechanism centers on the BRUEXECLOG environmental variable, which is designed to specify the location of execution logs within the backup process. When a user sets this variable to point to an arbitrary file path, the backup software fails to properly validate or sanitize the specified path, allowing attackers to redirect log data to any file on the system. This misconfiguration enables attackers to append data to existing files, potentially overwriting critical system files, log files, or configuration data that the backup software manages. The vulnerability demonstrates poor input validation and inadequate path sanitization practices, which are fundamental security controls that should prevent such arbitrary file access patterns.
The operational impact of this vulnerability extends beyond simple data corruption or modification, as it can be leveraged to compromise system integrity and availability. Local attackers can use this flaw to inject malicious content into system logs, potentially masking their activities or creating persistent backdoors within the backup infrastructure. The ability to append data to arbitrary files means that attackers could manipulate system files, configuration settings, or even critical backup archives that contain sensitive data. This vulnerability particularly affects environments where backup operations run with elevated privileges, as the appended data could then be executed or processed by the system, creating potential privilege escalation pathways.
Security practitioners should consider this vulnerability in the context of broader software security principles and attack patterns documented in the attack mitigation framework. The flaw aligns with CWE-22 Path Traversal and CWE-73 Path Traversal, which emphasize the critical importance of validating and sanitizing file paths before processing. From an attack perspective, this vulnerability fits within the attack technique category of privilege escalation and persistence mechanisms, as outlined in the MITRE ATT&CK framework. Organizations should implement strict access controls for backup utilities, regularly audit system configurations, and ensure that environmental variables are properly validated before being processed by system utilities. Additionally, the vulnerability highlights the importance of least privilege principles and proper input validation in all system components, particularly those that handle file I/O operations and system configuration management.