CVE-2021-21908 in Metal Detectors iC Module CMA
Summary
by MITRE • 12/22/2021
Specially-crafted command line arguments can lead to arbitrary file deletion. The handle_delete function does not attempt to sanitize or otherwise validate the contents of the [file] parameter (passed to the function as argv[1]), allowing an authenticated attacker to supply directory traversal primitives and delete semi-arbitrary files.
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Analysis
by VulDB Data Team • 12/26/2021
The vulnerability identified as CVE-2021-21908 represents a critical directory traversal flaw within a command line utility that processes file deletion operations. This vulnerability exists in the handle_delete function where input validation is completely absent for the file parameter. The function receives the file path through argv[1] without any sanitization or validation measures, creating a pathway for malicious input manipulation. An authenticated attacker can exploit this weakness by crafting specially formatted command line arguments that include directory traversal sequences such as ../ or ..\ to navigate outside the intended directory boundaries.
The technical implementation of this vulnerability stems from improper input validation practices that violate fundamental security principles outlined in CWE-22, which addresses directory traversal vulnerabilities. When the handle_delete function processes the unvalidated file parameter, it directly uses the supplied path without any checks against malicious patterns or directory traversal sequences. This allows an attacker who has authentication access to the system to manipulate the file deletion process and potentially target files outside the intended scope. The vulnerability is particularly dangerous because it operates within the context of an authenticated user, meaning that an attacker who has already gained access to the system can leverage this flaw to escalate their privileges or cause additional damage.
The operational impact of CVE-2021-21908 extends beyond simple file deletion capabilities, as it can enable attackers to compromise system integrity and potentially access sensitive data. An authenticated attacker can use this vulnerability to delete critical system files, configuration files, or even user data, leading to service disruption, data loss, or system instability. The vulnerability is classified as a command injection or path traversal issue that can be leveraged as part of broader attack chains within the MITRE ATT&CK framework, particularly under the techniques related to privilege escalation and persistence. The affected system becomes vulnerable to unauthorized file manipulation, which could result in complete system compromise if critical system files are targeted.
Mitigation strategies for this vulnerability require immediate implementation of input validation and sanitization measures within the handle_delete function. The most effective approach involves implementing strict parameter validation that rejects any input containing directory traversal sequences or special characters that could manipulate file paths. Organizations should implement proper path normalization and validation techniques that ensure file operations occur only within designated directories. Additionally, the principle of least privilege should be enforced to limit the impact of potential exploitation, ensuring that the utility operates with minimal required permissions. Security patches should be applied immediately, and system administrators should conduct thorough audits of similar functions within the application to identify and remediate other potential path traversal vulnerabilities. The vulnerability also highlights the importance of input validation as a core security control and demonstrates how simple oversight in parameter handling can lead to significant security implications.