CVE-2020-26062 in Unified Computing System
Summary
by MITRE • 11/18/2024
A vulnerability in Cisco Integrated Management Controller could allow an unauthenticated, remote attacker to enumerate valid usernames within the vulnerable application. The vulnerability is due to differences in authentication responses sent back from the application as part of an authentication attempt. An attacker could exploit this vulnerability by sending authentication requests to the affected application. A successful exploit could allow the attacker to confirm the names of administrative user accounts for use in further attacks.There are no workarounds that address this vulnerability.
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Analysis
by VulDB Data Team • 08/06/2025
This vulnerability exists within Cisco's Integrated Management Controller, a critical component responsible for remote management and monitoring of network infrastructure devices. The flaw represents a classic timing attack scenario where the application provides distinguishable responses based on whether authentication attempts target valid or invalid user accounts. The vulnerability stems from inconsistent error handling mechanisms that reveal information about account validity through subtle differences in response timing or message structure. Attackers can exploit this weakness by systematically sending authentication requests and analyzing the responses to determine which usernames are legitimate within the system. This type of information disclosure directly enables credential stuffing attacks and facilitates targeted brute force attempts against administrative accounts. The vulnerability is particularly concerning because it affects the management interface of network devices, potentially providing attackers with elevated privileges and complete control over the affected infrastructure. According to CWE classification, this represents a weakness in the authentication mechanism where the system reveals information that should remain confidential, specifically CWE-200 - Information Exposure. The vulnerability aligns with ATT&CK technique T1110.001 - Brute Force: Password Guessing, as it provides attackers with valid target accounts for more sophisticated credential-based attacks. The lack of workarounds means that organizations cannot implement temporary mitigations while awaiting patches, leaving them exposed to potential exploitation. The attack requires no authentication credentials initially, making it particularly dangerous as attackers can silently gather intelligence about valid administrative accounts without raising immediate detection alarms.
The operational impact of this vulnerability extends beyond simple credential enumeration, as it fundamentally undermines the security posture of network infrastructure devices managed through Cisco IMC. Once attackers have identified valid administrative usernames, they can proceed with more advanced attack vectors including password spraying, dictionary attacks, or credential reuse against other systems within the network perimeter. The vulnerability affects the core authentication service of the management controller, which typically handles critical functions such as firmware updates, configuration changes, and system monitoring. Organizations relying on Cisco IMC for device management face significant risk as this vulnerability could enable attackers to gain unauthorized access to network infrastructure, potentially leading to complete network compromise. The timing-based nature of the response differences makes this vulnerability particularly challenging to detect through traditional network monitoring, as the enumeration process occurs during normal authentication flows. This weakness essentially creates a backdoor for attackers to map out administrative user accounts without triggering obvious security alerts, making it a preferred target for reconnaissance phases of cyber attacks. The vulnerability demonstrates poor security implementation practices where the system's response behavior inadvertently leaks sensitive information about its internal state, violating fundamental security principles of least privilege and information hiding.
Mitigation strategies for this vulnerability require immediate patch deployment from Cisco, as no effective workarounds exist for the underlying authentication implementation flaw. Organizations should prioritize patching all affected Cisco Integrated Management Controller instances, particularly those managing critical network infrastructure components. Network segmentation and access control measures should be implemented to limit exposure of management interfaces to trusted networks only, reducing the attack surface available to remote adversaries. Security monitoring should be enhanced to detect unusual patterns of authentication requests that might indicate enumeration attempts, though the timing-based nature of the vulnerability makes detection challenging. Network administrators should review and tighten access controls for management interfaces, implementing multi-factor authentication where possible and regularly auditing administrative account usage. The vulnerability highlights the importance of proper error handling in security-sensitive applications, where responses should always be consistent regardless of whether authentication attempts succeed or fail. Organizations should also consider implementing intrusion detection systems specifically tuned to detect authentication enumeration patterns and monitor for the subtle timing differences that characterize this vulnerability. Regular security assessments should include testing for similar timing-based information disclosure vulnerabilities in other network management systems and applications. Given the severity and lack of mitigations, immediate action is required to address this vulnerability across all affected Cisco IMC installations to prevent potential compromise of critical network infrastructure components.