CVE-2011-3589 in kexec-tools
Summary
by MITRE
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, uses world-readable permissions for vmcore files, which allows local users to obtain sensitive information by inspecting the file content, as demonstrated by a search for a root SSH key.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability identified as CVE-2011-3589 represents a critical privilege escalation risk within the Red Hat kexec-tools package ecosystem. This issue affects the mkdumprd script which is responsible for creating crash dump initialization images in systems utilizing the kexec kernel feature. The vulnerability stems from improper file permission handling during the creation of vmcore files, which are essential for system crash analysis and debugging operations. The flaw exists in kexec-tools versions 1.x prior to 1.102pre-154 and 2.x prior to 2.0.0-209, making it a long-standing security issue that impacted numerous enterprise Linux distributions including Red Hat Enterprise Linux.
The technical implementation of this vulnerability involves the mkdumprd script creating vmcore files with world-readable permissions, typically set to 0644 or similar permissive modes. This design flaw allows any local user on the system to access these files through standard file system operations. The vmcore files contain memory dumps from kernel crashes, which can include sensitive information such as kernel memory contents, process information, and potentially credential data. The vulnerability specifically demonstrates how an attacker could search through these files to locate and extract root SSH private keys, which would provide unauthorized access to the system. This represents a classic case of insecure file permissions leading to information disclosure, with the flaw classified under CWE-732: Incorrect Permission Assignment for Critical Resource.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a persistent backdoor for local attackers to escalate privileges and maintain access to compromised systems. Attackers can leverage this vulnerability to gain access to system-level information that would normally be restricted to privileged processes or administrators. The vulnerability is particularly concerning because it operates at the system level without requiring elevated privileges, making it difficult to detect through traditional access control mechanisms. The attack vector is straightforward - any local user can simply read the world-readable vmcore files and extract sensitive information, with the potential for credential theft, system compromise, and further lateral movement within the network.
Mitigation strategies for CVE-2011-3589 require immediate patching of affected kexec-tools packages to ensure proper file permissions are enforced during vmcore file creation. Organizations should implement regular security updates and maintain current versions of system tools to prevent such vulnerabilities from persisting. The fix typically involves modifying the mkdumprd script to create vmcore files with restrictive permissions, ensuring that only authorized processes or users can access these critical system files. Additionally, system administrators should conduct periodic audits of file permissions for crash dump directories and implement monitoring to detect unauthorized access attempts to sensitive system files. This vulnerability aligns with ATT&CK technique T1005: Data from Local System, demonstrating how local privilege escalation can occur through improper file permissions and information disclosure. The remediation process should also include reviewing and hardening system configurations to prevent similar issues in other components that may create sensitive files with inadequate access controls.