CVE-2000-0781 in ARCserve Backup
Summary
by MITRE
uagentsetup in ARCServeIT Client Agent 6.62 does not properly check for the existence or ownership of a temporary file which is moved to the agent.cfg configuration file, which allows local users to execute arbitrary commands by modifying the temporary file before it is moved.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability identified as CVE-2000-0781 resides within the uagentsetup component of ARCServeIT Client Agent version 6.62, representing a critical security flaw that exploits improper file handling mechanisms. This issue manifests when the system creates a temporary file during the configuration process and subsequently moves it to become the agent.cfg configuration file without adequate verification of the temporary file's existence or ownership. The flaw stems from a fundamental lack of input validation and proper privilege management during file operations, creating an exploitable condition that can be leveraged by local attackers to execute arbitrary code on the system.
The technical implementation of this vulnerability involves a race condition scenario where the temporary file is created with insufficient access controls and the system does not validate whether the file was properly created or if it has been tampered with before being moved into the final configuration location. This type of flaw falls under CWE-362, which specifically addresses race conditions that can lead to privilege escalation and unauthorized code execution. The vulnerability is particularly concerning because it requires only local system access to exploit, meaning that any user with access to the system can potentially leverage this weakness to gain elevated privileges and execute malicious commands with the privileges of the ARCServeIT agent process.
From an operational perspective, this vulnerability presents a significant risk to enterprise environments that rely on ARCServeIT for backup and recovery operations, as it allows local attackers to potentially compromise the integrity of the backup infrastructure. The attack vector is straightforward: an attacker modifies the temporary file before it is moved to the agent.cfg location, thereby injecting malicious code that will execute when the agent process reads the configuration file. This can result in unauthorized data access, system compromise, or disruption of backup operations that are critical to business continuity. The vulnerability aligns with ATT&CK technique T1068, which covers 'Local Port Forwarding' and 'Exploitation for Privilege Escalation' through local system weaknesses, and demonstrates how seemingly benign file handling operations can create substantial security risks.
Mitigation strategies for this vulnerability should focus on immediate patching of the ARCServeIT Client Agent to version 6.63 or later, which addresses the improper file handling issue. System administrators should also implement proper file access controls and privilege separation to minimize the impact of such vulnerabilities. Additionally, monitoring for unauthorized file modifications in temporary directories and implementing file integrity checking mechanisms can help detect exploitation attempts. The remediation process should include verifying that temporary files are created with appropriate permissions and that proper ownership validation occurs before any file movement operations are executed, thereby preventing the exploitation of similar race condition vulnerabilities in other software components.