CVE-2017-12477 in Backup
Summary
by MITRE
It was discovered that the bpserverd proprietary protocol in Unitrends Backup (UB) before 10.0.0, as invoked through xinetd, has an issue in which its authentication can be bypassed. A remote attacker could use this issue to execute arbitrary commands with root privilege on the target system.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/12/2024
The vulnerability identified as CVE-2017-12477 represents a critical authentication bypass flaw in the proprietary bpserverd protocol implementation within Unitrends Backup software versions prior to 10.0.0. This issue manifests through the protocol's integration with xinetd service management framework, creating a pathway for unauthorized remote exploitation that ultimately allows attackers to achieve privilege escalation to root level access on affected systems. The flaw exists in the authentication mechanism of the bpserverd daemon, which is responsible for handling backup operations and communication within the Unitrends ecosystem.
The technical implementation of this vulnerability stems from improper authentication handling within the bpserverd protocol implementation. When the protocol is invoked through xinetd, the authentication checks fail to properly validate incoming connections, allowing malicious actors to bypass the intended security controls. This authentication bypass occurs at the protocol level where the server fails to adequately verify client credentials before processing commands, enabling arbitrary command execution. The vulnerability specifically affects systems where the bpserverd service operates through xinetd, which is a common service daemon used to manage internet services on Unix-like systems. This architectural dependency amplifies the impact as xinetd's configuration and operation directly influence how authentication is handled for the vulnerable protocol.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with complete system compromise capabilities. Remote attackers who successfully exploit this vulnerability can execute arbitrary commands with root privileges, effectively granting them full control over the target system. This level of access enables attackers to modify system files, install malware, create backdoors, and exfiltrate sensitive data without detection. The privilege escalation aspect of the vulnerability means that even if other security controls are in place, the authentication bypass renders them ineffective, as the attacker gains the highest level of system access possible. This makes the vulnerability particularly dangerous in enterprise environments where backup systems often contain sensitive data and operate with elevated privileges.
Security professionals should implement immediate mitigations including upgrading to Unitrends Backup version 10.0.0 or later, which contains the necessary patches to address the authentication bypass issue. Organizations should also consider disabling the bpserverd service if it is not essential for operations, or implementing network-level restrictions to limit access to the affected protocol. The vulnerability aligns with CWE-287, which addresses improper authentication issues, and maps to ATT&CK technique T1068, involving exploit for privilege escalation. Additionally, this issue demonstrates characteristics of T1190, which involves exploiting vulnerabilities in remote services, making it a significant concern for organizations relying on backup infrastructure for data protection and recovery operations. Network segmentation and monitoring of xinetd services should be implemented to detect potential exploitation attempts and provide early warning capabilities.