CVE-2019-10147 in rkt
Summary
by MITRE
rkt through version 1.30.0 does not isolate processes in containers that are run with `rkt enter`. Processes run with `rkt enter` are not limited by cgroups during stage 2 (the actual environment in which the applications run). Compromised containers could exploit this flaw to access host resources.
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Analysis
by VulDB Data Team • 09/26/2023
The vulnerability identified as CVE-2019-10147 affects the rkt container runtime version 1.30.0 and earlier, presenting a critical isolation flaw that undermines the fundamental security model of containerization. This vulnerability specifically impacts the `rkt enter` command functionality where containers are executed with elevated privileges that bypass essential cgroup limitations. The flaw exists in the stage 2 execution environment where applications actually run, creating a scenario where compromised containers can exploit this weakness to gain unauthorized access to host resources. The root cause lies in the improper implementation of process isolation mechanisms during container entry operations, where cgroup restrictions are not properly enforced for processes initiated through the enter command.
The technical implementation of this vulnerability stems from the rkt runtime's failure to establish proper cgroup boundaries when executing processes within containers using the `rkt enter` functionality. According to CWE-254, this represents a weakness in the security model where insufficient isolation mechanisms allow privilege escalation and resource access violations. The cgroup subsystem, which serves as a fundamental Linux kernel feature for process resource management and isolation, is bypassed during stage 2 execution, creating a direct pathway for malicious processes to access host system resources. This flaw operates at the kernel level where process isolation is typically enforced through cgroup controllers that limit CPU, memory, and I/O resources. The vulnerability manifests when processes launched through `rkt enter` retain access to host resources that should be restricted by container isolation policies.
The operational impact of CVE-2019-10147 extends beyond simple privilege escalation to encompass complete system compromise potential. Attackers exploiting this vulnerability can leverage the lack of cgroup restrictions to access host filesystems, network interfaces, and system processes that should remain isolated from containerized applications. This vulnerability aligns with ATT&CK technique T1068 which describes local privilege escalation through process manipulation and resource access. The compromised container environment allows attackers to perform actions such as process monitoring, data exfiltration, and system reconnaissance that would normally be prevented by proper container isolation. Additionally, the vulnerability can be exploited for lateral movement within the host system, as processes can access host network resources and potentially other containers running on the same host.
Mitigation strategies for CVE-2019-10147 should focus on immediate patching of affected rkt versions to 1.31.0 or later where the cgroup isolation has been properly implemented. Organizations should implement strict access controls for the `rkt enter` command, limiting its usage to trusted administrators and eliminating unnecessary privilege escalation opportunities. System administrators should conduct comprehensive audits of containerized environments to identify any instances where `rkt enter` functionality is being used in production. The implementation of additional security monitoring for unusual process behaviors and resource access patterns can help detect exploitation attempts. Organizations should also consider implementing container runtime security solutions that provide additional layers of isolation and monitoring beyond the native cgroup mechanisms. According to NIST SP 800-190, container security should include proper isolation controls and privilege limiting measures to prevent unauthorized access to host resources. Regular security assessments and vulnerability scanning should be performed to ensure that container runtime environments maintain proper isolation boundaries and that cgroup restrictions are properly enforced for all container execution paths.