CVE-2022-21945 in cscreen
Summary
by MITRE • 03/16/2022
A Insecure Temporary File vulnerability in cscreen of openSUSE Factory allows local attackers to cause DoS for cscreen and a system DoS for non-default systems. This issue affects: openSUSE Factory cscreen version 1.2-1.3 and prior versions.
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Analysis
by VulDB Data Team • 03/19/2022
The vulnerability CVE-2022-21945 represents an insecure temporary file handling issue within the cscreen application running on openSUSE Factory systems. This flaw resides in the cscreen utility which is designed to provide screen management capabilities for terminal sessions, making it a critical component in system administration environments. The vulnerability specifically affects versions 1.2-1.3 and earlier of the cscreen package distributed through openSUSE Factory, creating a potential attack vector for local adversaries seeking to disrupt system operations. The issue manifests as a temporary file security weakness that can be exploited to execute malicious code or manipulate system resources through improper file handling mechanisms.
The technical implementation of this vulnerability stems from inadequate temporary file creation and management practices within the cscreen application. When cscreen creates temporary files during its operation, it fails to properly validate or secure the temporary file paths, potentially allowing local attackers to predict or manipulate temporary file locations. This insecure temporary file handling creates opportunities for privilege escalation and system compromise. According to CWE classification, this vulnerability maps to CWE-377: Insecure Temporary File, which specifically addresses the creation of temporary files with insecure permissions or predictable names that can be exploited by attackers. The flaw enables attackers to potentially overwrite or manipulate temporary files, leading to unauthorized code execution or denial of service conditions.
The operational impact of CVE-2022-21945 extends beyond simple service disruption to potentially cause complete system DoS conditions on affected non-default configurations. Local attackers can leverage this vulnerability to compromise the cscreen process and subsequently affect broader system stability. In default system configurations, the primary impact is denial of service for the cscreen application itself, but on non-default systems with specific configurations, the vulnerability can escalate to system-wide disruption. This vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, as attackers can exploit the insecure temporary file creation to execute malicious commands. The attack surface is particularly concerning in environments where cscreen is used for critical system monitoring or administration tasks, as the DoS condition can prevent legitimate system management operations.
Mitigation strategies for this vulnerability require immediate patching of affected cscreen versions to address the insecure temporary file handling implementation. System administrators should upgrade to cscreen version 1.2-1.4 or later where the temporary file creation mechanisms have been properly secured. Additionally, implementing proper file permissions and secure temporary file creation practices can help reduce the attack surface. Organizations should also consider monitoring for unauthorized temporary file creation patterns and implementing process isolation for critical system utilities. The vulnerability highlights the importance of proper temporary file handling as outlined in the OWASP Top Ten and other security frameworks, emphasizing the need for secure coding practices that prevent predictable temporary file creation and ensure proper file permissions are maintained throughout the application lifecycle.