CVE-2003-1475 in NetBus
Summary
by MITRE
Netbus 1.5 through 1.7 allows more than one client to be connected at the same time, but only prompts the first connection for authentication, which allows remote attackers to gain access.
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Analysis
by VulDB Data Team • 03/08/2021
The vulnerability described in CVE-2003-1475 represents a critical authentication bypass flaw in Netbus remote administration software versions 1.5 through 1.7. This vulnerability falls under the category of improper authentication mechanisms and aligns with CWE-287 which addresses authentication bypass through multiple means. The flaw stems from the software's design where only the initial connection attempt requires authentication credentials, while subsequent connections are automatically granted access without proper verification. This architectural weakness creates a significant security gap that adversaries can exploit to gain unauthorized access to systems running vulnerable versions of Netbus.
The technical implementation of this vulnerability demonstrates a fundamental flaw in connection handling logic within the Netbus remote administration tool. When multiple clients attempt to connect to the same Netbus server instance, the authentication mechanism only validates the credentials of the first connection attempt and subsequently accepts additional connections without re-authentication. This behavior violates the principle of least privilege and creates an attack surface where unauthorized users can establish connections simply by being the second or subsequent user to attempt access. The vulnerability specifically affects the authentication flow and connection management components of the software, making it particularly dangerous in environments where the tool is deployed for legitimate remote administration purposes.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it enables persistent and undetected compromise of systems. Attackers can exploit this flaw to gain remote control of vulnerable systems without the need for valid credentials, potentially leading to complete system compromise, data exfiltration, and lateral movement within networks. The vulnerability is particularly concerning because it operates silently without alerting administrators to unauthorized access attempts, making detection extremely difficult. This characteristic aligns with ATT&CK technique T1071.004 for application layer protocol usage and T1021.002 for remote services, as the compromised system becomes an entry point for further malicious activities. Organizations using vulnerable Netbus versions face significant risk of persistent threats that can remain undetected for extended periods.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security posture improvements. The most effective immediate solution involves upgrading to a patched version of Netbus or migrating to more modern and secure remote administration tools that properly implement authentication for each connection attempt. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable systems, while monitoring for unauthorized connections to the Netbus service. Security controls should include network-based intrusion detection systems that can identify suspicious connection patterns and behavioral analysis tools that can detect anomalous access attempts. Additionally, regular security assessments and vulnerability scanning should be conducted to identify and remediate similar authentication bypass vulnerabilities in other software components. The remediation process must also include proper configuration management to ensure that only authorized users can establish connections to remote administration services, and that connection logging is properly implemented to detect unauthorized access attempts.