CVE-2018-19638 in Supportutils
Summary
by MITRE
In supportutils, before version 3.1-5.7.1 and if pacemaker is installed on the system, an unprivileged user could have overwritten arbitrary files in the directory that is used by supportutils to collect the log files.
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Analysis
by VulDB Data Team • 07/26/2023
The vulnerability identified as CVE-2018-19638 resides within the supportutils package, a tool commonly used for collecting system information and logs for diagnostic purposes in enterprise environments. This issue specifically affects systems running pacemaker, which is a high-availability cluster resource manager that coordinates services across multiple nodes in a cluster environment. The flaw manifests when supportutils is executed on systems where pacemaker is installed, creating a security risk that could be exploited by unprivileged users to manipulate system files. The vulnerability stems from improper handling of temporary directories and file permissions during the log collection process, allowing local users to potentially overwrite critical system files with malicious content.
The technical implementation of this vulnerability involves a race condition or insecure temporary file creation mechanism within supportutils when it processes logs from pacemaker services. When the tool executes, it creates temporary directories and files in locations that are not properly secured against unauthorized access. This flaw is particularly dangerous because it allows an unprivileged user to manipulate the file system in ways that could compromise system integrity and potentially escalate privileges. The vulnerability is classified under CWE-377, which deals with insecure temporary file handling, and specifically relates to CWE-276, which addresses incorrect permissions for privileged system resources. The insecure file handling allows for potential file overwrite operations that could be exploited to modify critical system files or inject malicious content into the logging infrastructure.
The operational impact of this vulnerability extends beyond simple file overwrite capabilities, as it creates potential attack vectors for privilege escalation and system compromise. An attacker could exploit this vulnerability to overwrite configuration files, log files, or even executable components that are processed by pacemaker or supportutils itself. This could result in denial of service conditions, data corruption, or more severe consequences if the overwritten files are part of the system's authentication or authorization mechanisms. The vulnerability is particularly concerning in clustered environments where pacemaker manages critical services, as it could allow attackers to disrupt cluster operations or gain unauthorized access to sensitive system resources. According to ATT&CK framework, this vulnerability aligns with techniques related to privilege escalation and persistence through file system manipulation.
Mitigation strategies for CVE-2018-19638 should focus on immediate patching of the supportutils package to version 3.1-5.7.1 or later, which contains the necessary fixes for the insecure temporary file handling. System administrators should also implement additional security controls such as restricting access to the supportutils tool and its temporary directories, ensuring proper file permissions are maintained, and monitoring for unauthorized file system modifications. Organizations should conduct security audits to identify systems running vulnerable versions of supportutils and pacemaker, particularly in clustered environments where the risk is heightened. The fix typically involves implementing proper temporary file creation with secure permissions, using atomic file operations, and ensuring that temporary directories are properly cleaned up after use. Additionally, network segmentation and access controls should be reviewed to limit local user access to critical system components and reduce the potential impact of such vulnerabilities in the broader security posture.