CVE-2011-3588 in kexec-tools
Summary
by MITRE
The SSH configuration in the Red Hat mkdumprd script for kexec-tools, as distributed in the kexec-tools 1.x before 1.102pre-154 and 2.x before 2.0.0-209 packages in Red Hat Enterprise Linux, disables the StrictHostKeyChecking option, which allows man-in-the-middle attackers to spoof kdump servers, and obtain sensitive core information, by using an arbitrary SSH key.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability described in CVE-2011-3588 represents a critical security flaw in the Red Hat kexec-tools package that affects systems running Red Hat Enterprise Linux versions prior to specific patch releases. This issue resides within the mkdumprd script which is responsible for creating kdump kernel crash dump images, and specifically impacts the SSH configuration used during the kdump process. The flaw manifests when the script disables the StrictHostKeyChecking SSH option, creating a pathway for malicious actors to exploit the system's trust mechanisms during crash dump operations.
The technical implementation of this vulnerability stems from the improper SSH configuration within the kexec-tools package where the StrictHostKeyChecking parameter is explicitly disabled. This configuration change removes the requirement for SSH clients to verify host keys against known hosts, allowing attackers to perform man-in-the-middle attacks by presenting forged SSH keys. The vulnerability operates at the network protocol level and specifically targets the SSH communication channel used by kdump to transfer crash information to remote servers. When the kdump process initiates SSH connections to collect crash data, the disabled host key checking means that any attacker positioned between the system and the target server can intercept and manipulate the communication without detection.
The operational impact of this vulnerability is significant as it enables attackers to gain access to sensitive core information that would normally be protected during system crash scenarios. During kdump operations, systems typically generate core dump files containing valuable system information including memory contents, process information, and potentially sensitive data from running applications. By disabling StrictHostKeyChecking, the vulnerability allows attackers to intercept these core dumps and potentially extract confidential information that could be used for further attacks or system compromise. The attack vector specifically targets the kdump server communication channel, making it particularly dangerous for systems that rely on remote crash dump collection for troubleshooting and forensic analysis.
This vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in the use of SSH configurations that fail to properly validate host keys, and represents a clear violation of secure communication principles. The ATT&CK framework categorizes this as a technique for credential access and defense evasion, as attackers can both obtain sensitive information through the compromised crash dump process and potentially establish persistence through manipulation of the kdump infrastructure. The flaw demonstrates poor security configuration management where default security settings are deliberately overridden without proper risk assessment, creating an attack surface that could be exploited by adversaries with network access to the target systems.
Mitigation strategies for this vulnerability require immediate patching of the kexec-tools package to versions that properly maintain the StrictHostKeyChecking option. System administrators should verify that SSH host key verification remains enabled during kdump operations and ensure that proper key management practices are implemented for kdump servers. Additionally, network segmentation and monitoring should be employed to detect unauthorized access attempts to kdump servers. Organizations should also review their overall kdump configuration to ensure that other security measures are properly implemented, including proper access controls for crash dump storage and network isolation of critical systems that perform crash dump operations. The vulnerability highlights the importance of maintaining secure default configurations and the need for regular security assessments of system components that handle sensitive data during system failure scenarios.