CVE-2021-3020 in Hawk
Summary
by MITRE • 08/26/2022
An issue was discovered in ClusterLabs Hawk (aka HA Web Konsole) through 2.3.0-15. It ships the binary hawk_invoke (built from tools/hawk_invoke.c), intended to be used as a setuid program. This allows the hacluster user to invoke certain commands as root (with an attempt to limit this to safe combinations). This user is able to execute an interactive "shell" that isn't limited to the commands specified in hawk_invoke, allowing escalation to root.
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Analysis
by VulDB Data Team • 10/02/2022
The vulnerability identified in CVE-2021-3020 affects ClusterLabs Hawk version 2.3.0-15 and earlier, representing a critical privilege escalation flaw within the HA Web Konsole management interface. This issue stems from the improper implementation of a setuid binary named hawk_invoke, which is designed to execute specific administrative commands with elevated privileges. The system's architecture permits the hacluster user, who typically operates with limited privileges, to leverage this setuid binary to gain root access, fundamentally undermining the principle of least privilege that is essential for secure system administration.
The technical flaw manifests through the design of the hawk_invoke binary, which was intended to restrict command execution to a predefined safe set of operations. However, the implementation contains a critical oversight that allows the hacluster user to bypass these intended restrictions and access an interactive shell environment. This shell environment is not properly confined to the limited command set specified in the hawk_invoke program, creating an unintended code execution pathway that directly leads to root privilege escalation. The vulnerability specifically exploits the trust model between the setuid binary and the underlying system shell, allowing arbitrary command execution beyond the intended scope.
The operational impact of this vulnerability is severe as it transforms a user with standard administrative privileges into a root-level attacker within the cluster management environment. This escalation enables an attacker to perform any action that requires root privileges, including modifying system files, accessing sensitive data, installing malicious software, or compromising the entire cluster infrastructure. The vulnerability affects systems where ClusterLabs Hawk is deployed as the primary management interface for High Availability clusters, potentially exposing critical infrastructure components to unauthorized access and control. The attack vector is particularly concerning because it requires minimal privileges to exploit, making it accessible to users who normally should not have root-level access to the system.
Mitigation strategies for this vulnerability should focus on immediate remediation through patching the ClusterLabs Hawk software to version 2.3.0-16 or later, which contains the necessary fixes to address the setuid binary implementation. Organizations should also implement additional security controls such as restricting access to the hawk_invoke binary, disabling the setuid bit on the binary if not strictly required, and implementing proper privilege separation mechanisms. The remediation process should include comprehensive system auditing to identify any potential exploitation attempts that may have occurred prior to patching. Security teams should also consider implementing monitoring solutions to detect unauthorized access attempts to setuid binaries and establish strict access controls for the hacluster user account to minimize the attack surface. This vulnerability aligns with CWE-276, which addresses improper privilege management, and represents a significant concern from an attacker perspective as outlined in the ATT&CK framework under privilege escalation techniques.