CVE-2021-1601 in Intersight Virtual Appliance
Summary
by MITRE • 07/22/2021
Multiple vulnerabilities in Cisco Intersight Virtual Appliance could allow an unauthenticated, adjacent attacker to access sensitive internal services from an external interface. These vulnerabilities are due to insufficient restrictions for IPv4 or IPv6 packets that are received on the external management interface. An attacker could exploit these vulnerabilities by sending specific traffic to this interface on an affected device. A successful exploit could allow the attacker to access sensitive internal services and make configuration changes on the affected device.
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Analysis
by VulDB Data Team • 07/27/2021
The Cisco Intersight Virtual Appliance represents a critical security vulnerability classified as CVE-2021-1601, which exposes organizations to significant risks through inadequate network interface controls. This vulnerability specifically targets the management interface of the appliance, creating a pathway for adjacent attackers to bypass security measures and gain unauthorized access to internal services. The flaw stems from insufficient packet filtering mechanisms that fail to properly validate incoming IPv4 or IPv6 traffic on the external management interface, effectively creating a backdoor that undermines the appliance's security posture.
The technical implementation of this vulnerability resides in the network stack's handling of external management traffic, where the appliance fails to enforce proper access controls between external and internal network segments. Attackers can exploit this weakness by crafting specific network packets that traverse the external management interface, potentially gaining access to internal services that should remain isolated from external exposure. This represents a classic case of insufficient network segmentation and access control enforcement, where the boundary between trusted internal services and untrusted external traffic becomes permeable due to inadequate packet validation mechanisms.
From an operational perspective, this vulnerability creates severe implications for organizations relying on Cisco Intersight Virtual Appliance for infrastructure management and monitoring. The ability for unauthenticated attackers to access sensitive internal services without proper authentication significantly increases the attack surface and potential for data compromise. Configuration changes that can be made through this vulnerability may include modifications to network settings, user permissions, or system parameters that could lead to further exploitation or disruption of services. The adjacent attacker requirement suggests that physical or network proximity is necessary, but this limitation does not sufficiently mitigate the risk given the potential for network-based exploitation or lateral movement.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, particularly under the techniques related to network infiltration and privilege escalation. The vulnerability aligns with CWE-284, which addresses improper access control mechanisms, and CWE-352, which covers cross-site request forgery conditions that can enable unauthorized actions. Organizations implementing Cisco Intersight Virtual Appliances must recognize this as a critical risk that requires immediate attention through patch management, network segmentation, and monitoring of external management interface traffic. The remediation strategy should include implementing proper firewall rules, disabling unnecessary external access, and conducting thorough network audits to identify potential exploitation attempts.
The broader implications extend beyond immediate exploitation to include potential for persistent access and data exfiltration capabilities. Attackers who successfully exploit this vulnerability may establish footholds within the network infrastructure, potentially using the appliance as a pivot point for further attacks against other systems. This makes the vulnerability particularly dangerous in enterprise environments where the appliance may serve as a central management point for critical infrastructure components. The lack of authentication requirements for accessing internal services through this interface creates a fundamental security flaw that undermines the appliance's ability to function as a secure management platform, requiring organizations to implement compensating controls such as network monitoring, intrusion detection systems, and regular security assessments to detect and prevent exploitation attempts.