CVE-2024-33522 in Calico
Summary
by MITRE • 04/30/2024
In vulnerable versions of Calico (v3.27.2 and below), Calico Enterprise (v3.19.0-1, v3.18.1, v3.17.3 and below), and Calico Cloud (v19.2.0 and below), an attacker who has local access to the Kubernetes node, can escalate their privileges by exploiting a vulnerability in the Calico CNI install binary. The issue arises from an incorrect SUID (Set User ID) bit configuration in the binary, combined with the ability to control the input binary, allowing an attacker to execute an arbitrary binary with elevated privileges.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/30/2024
The vulnerability identified as CVE-2024-33522 represents a critical privilege escalation flaw affecting multiple Calico components including Calico, Calico Enterprise, and Calico Cloud across their respective versions. This vulnerability specifically targets the Calico Container Network Interface (CNI) install binary that runs with elevated privileges on Kubernetes nodes. The flaw stems from an improper configuration of the SUID bit, which is a Unix security mechanism that allows a program to execute with the permissions of the file owner rather than the user who invoked it. When the SUID bit is incorrectly set, it creates an opportunity for privilege escalation attacks that can be exploited by local attackers.
The technical implementation of this vulnerability involves the manipulation of the Calico CNI install binary through a combination of factors that create a dangerous attack surface. Attackers with local access to a Kubernetes node can exploit the incorrect SUID configuration by controlling the input parameters passed to the vulnerable binary. This allows them to execute arbitrary code with elevated privileges, effectively bypassing normal access controls and gaining root-level permissions on the compromised node. The vulnerability is particularly concerning because it leverages the inherent trust placed in system binaries and the implicit assumption that SUID binaries are properly secured. According to CWE-276, this represents an improper privileges assignment vulnerability where the system fails to properly manage the execution context of privileged programs, making it a direct violation of the principle of least privilege that is fundamental to secure system design.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model of Kubernetes clusters that rely on Calico for network policy enforcement and container networking. When an attacker successfully exploits this vulnerability, they gain the ability to modify system files, install malicious software, access sensitive data, and potentially move laterally within the cluster. The attack vector is particularly dangerous because it requires only local access to the node, meaning that an attacker who has already gained access to the system through other means can leverage this vulnerability to achieve persistent, elevated access. This type of vulnerability aligns with ATT&CK technique T1068, which describes the exploitation of local privilege escalation vulnerabilities, and can be classified under the broader category of privilege escalation attacks that target system binaries and their execution contexts.
Mitigation strategies for CVE-2024-33522 must address both the immediate configuration issues and implement broader security controls to prevent exploitation. Organizations should immediately update to patched versions of Calico, Calico Enterprise, and Calico Cloud where available, as these releases should contain corrected SUID bit configurations and proper privilege management. System administrators should also implement strict binary integrity controls, including monitoring for unauthorized modifications to critical system binaries and implementing file integrity monitoring solutions. The remediation process should include verification that the SUID bit is properly configured on the Calico CNI install binary and that no unauthorized modifications have been made to the binary or its dependencies. Additionally, organizations should consider implementing additional security controls such as kernel lockdown mechanisms, mandatory access controls, and container runtime security policies that can prevent unauthorized binary execution even if privilege escalation attempts occur. The vulnerability demonstrates the importance of proper privilege management and the need for regular security auditing of system binaries, particularly those with elevated privileges, to ensure that security mechanisms like SUID are correctly implemented and maintained.