CVE-2020-10807 in Caldera
Summary
by MITRE
auth_svc in Caldera before 2.6.5 allows authentication bypass (for REST API requests) via a forged "localhost" string in the HTTP Host header.
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Analysis
by VulDB Data Team • 04/18/2024
The vulnerability identified as CVE-2020-10807 affects the Caldera security platform version 2.6.4 and earlier, specifically within the auth_svc component responsible for authentication handling in REST API requests. This authentication bypass flaw stems from insufficient validation of the HTTP Host header parameter, creating a critical security weakness that could allow unauthorized access to the platform's administrative functions and sensitive operations. The vulnerability resides in the platform's trust mechanism for local connections, where the system incorrectly accepts a forged localhost string in the Host header as a legitimate local connection indicator.
The technical implementation of this vulnerability exploits a trust relationship that exists between the Caldera platform and localhost connections. When a client makes REST API requests to the Caldera server, the authentication service examines the HTTP Host header to determine whether the request originates from a local system. The flaw occurs because the system accepts any Host header value that contains the string "localhost" regardless of the actual connection source or port. This allows an attacker to craft malicious HTTP requests with a forged Host header containing "localhost" while connecting from an external IP address or port, effectively bypassing the local authentication checks that should normally restrict access to administrative functions. The vulnerability represents a classic case of improper input validation and trust assumption, aligning with CWE-284 Access Control Issues where insufficient access control mechanisms allow unauthorized access.
The operational impact of this authentication bypass vulnerability is significant, as it enables remote attackers to gain unauthorized access to the Caldera platform's administrative interface and REST API endpoints without proper credentials. An attacker could potentially execute commands, modify configurations, access sensitive data, or manipulate the platform's operational capabilities. This vulnerability particularly affects organizations using Caldera for red team operations and adversary emulation, where unauthorized access could compromise the integrity of security assessments and provide attackers with access to advanced exploitation capabilities. The risk is amplified because the bypass affects the core authentication mechanism, potentially allowing full administrative control over the platform's operations and data. The vulnerability could also enable lateral movement within networks if Caldera is integrated with other security tools or systems.
Mitigation strategies for CVE-2020-10807 should prioritize upgrading to Caldera version 2.6.5 or later, which includes proper validation of the Host header and implementation of more robust authentication checks. Organizations should also implement additional network-level controls such as firewall rules to restrict access to Caldera's REST API endpoints to trusted IP addresses only, and deploy network monitoring solutions to detect suspicious Host header values. The implementation of proper input validation and strict header verification mechanisms should be enforced across all authentication services, following security best practices that align with the principle of least privilege and defense in depth. Security teams should also conduct regular vulnerability assessments to identify similar trust assumption flaws in other components and ensure that all authentication mechanisms properly validate connection origins rather than relying solely on header values that can be easily forged. This vulnerability demonstrates the importance of implementing proper access control validation and avoiding assumptions about connection origins based on header values that can be manipulated by attackers, which aligns with ATT&CK technique T1078 Valid Accounts and T1566 Phishing with Social Engineering approaches that exploit authentication bypass vulnerabilities.