CVE-2011-1828 in usb-creator
Summary
by MITRE
usb-creator-helper in usb-creator before 0.2.28.3 does not enforce intended PolicyKit restrictions, which allows local users to perform arbitrary unmount operations via the UnmountFile method in a dbus-send command.
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Analysis
by VulDB Data Team • 11/07/2021
The vulnerability identified as CVE-2011-1828 resides within the usb-creator-helper component of the usb-creator package, specifically affecting versions prior to 0.2.28.3. This flaw represents a critical authorization bypass that undermines the security controls designed to protect system resources from unauthorized manipulation. The usb-creator-helper utility is responsible for managing USB device creation processes and includes functionality for unmounting filesystems during these operations. The vulnerability manifests through improper enforcement of PolicyKit restrictions, which are essential access control mechanisms that govern how applications can perform privileged operations on Unix-like systems.
The technical flaw exploits a weakness in the dbus interface implementation where the UnmountFile method lacks proper authorization checks. When a local user executes a dbus-send command targeting this method, they can bypass the intended PolicyKit policies that should restrict unmount operations to authorized processes only. This represents a classic case of insufficient authorization checking, classified under CWE-863, where the system fails to verify that the requesting entity has proper privileges before executing sensitive operations. The vulnerability allows an attacker to perform arbitrary unmount operations on any mounted filesystem, potentially leading to data corruption, unauthorized access to sensitive information, or system instability.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables local users to manipulate the system's storage subsystem in ways that could compromise data integrity and system security. An attacker could unmount critical system partitions, disrupt ongoing processes, or create conditions that facilitate further attacks. The vulnerability is particularly concerning because it operates at the system level and requires no elevated privileges to exploit, making it accessible to any local user with basic system access. This aligns with ATT&CK technique T1068, which describes the exploitation of legitimate credentials and privileges to gain unauthorized access to system resources.
Mitigation strategies for this vulnerability must address both the immediate security gap and the underlying architectural issues that permitted the authorization bypass. The primary fix involves updating the usb-creator package to version 0.2.28.3 or later, where proper PolicyKit enforcement has been implemented. System administrators should also conduct thorough security audits to identify other components that may be vulnerable to similar authorization bypass issues. Additional protective measures include implementing proper access controls for dbus interfaces, ensuring that PolicyKit rules are correctly configured, and monitoring for unauthorized unmount operations. The vulnerability highlights the importance of proper privilege separation and the need for comprehensive security testing of system components that interact with privileged interfaces, particularly those involving storage management operations that could affect system stability and data integrity.