CVE-2021-21597 in Wyse ThinOS
Summary
by MITRE • 08/11/2021
Dell Wyse ThinOS, version 9.0, contains a Sensitive Information Disclosure Vulnerability. An authenticated malicious user with physical access to the system could exploit this vulnerability to read sensitive information written to the log files.
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Analysis
by VulDB Data Team • 08/15/2021
The vulnerability identified as CVE-2021-21597 affects Dell Wyse ThinOS version 9.0 and represents a sensitive information disclosure flaw that poses significant security risks when combined with physical access privileges. This vulnerability resides within the thin client operating system's logging mechanisms, where sensitive data may be inadvertently exposed through log file contents. The issue specifically targets authenticated users who have gained physical access to the system, creating a dangerous attack vector that leverages both authentication credentials and direct hardware interaction capabilities.
The technical implementation of this vulnerability stems from inadequate sanitization of log file entries within the Wyse ThinOS environment. When authenticated users interact with the system, certain operations generate log entries that contain sensitive information such as passwords, session tokens, or other confidential data. The flaw occurs because the logging subsystem does not properly filter or redact sensitive information before writing it to persistent storage, allowing subsequent access to these log files to reveal confidential data. This represents a classic case of insufficient logging security controls and improper data handling practices.
The operational impact of CVE-2021-21597 extends beyond simple information disclosure, as it creates opportunities for privilege escalation and broader system compromise. An attacker with physical access and valid credentials can exploit this vulnerability to gain insights into system operations, user authentication mechanisms, and potentially extract credentials or session information that could be used for further attacks. The combination of physical access with authenticated privileges creates a particularly dangerous scenario where attackers can leverage the thin client's logging infrastructure to uncover sensitive data that should remain protected. This vulnerability aligns with CWE-200, which addresses the disclosure of sensitive information, and demonstrates how improper access control and logging practices can create persistent security weaknesses.
From an adversary perspective, this vulnerability maps directly to several ATT&CK techniques including T1070.004 (Indicator Removal on Host: File Deletion) and T1567.002 (Exfiltration Over Web Service: Exfiltration to Cloud Storage). The threat actor could exploit this to gather intelligence about system configurations, user activities, and authentication mechanisms, potentially leading to more sophisticated attacks. The vulnerability also represents a failure in the principle of least privilege, as the system does not adequately protect sensitive data even within its own logging infrastructure. Organizations using Dell Wyse ThinOS 9.0 should implement immediate mitigations including log file access controls, regular log file audits, and enhanced logging sanitization procedures to prevent unauthorized access to sensitive information stored within system logs.
The vulnerability highlights the importance of proper logging security practices and demonstrates how seemingly benign system components can become attack vectors when security controls are inadequate. Organizations should consider implementing comprehensive logging policies that ensure sensitive information is never written to log files or that such information is properly redacted before storage. This vulnerability also underscores the need for regular security assessments of thin client environments, where physical access combined with authentication privileges can create unique attack surfaces that traditional network-based security measures may not adequately protect against.