CVE-2010-4176 in udev
Summary
by MITRE
plymouth-pretrigger.sh in dracut and udev, when running on Fedora 13 and 14, sets weak permissions for the /dev/systty device file, which allows remote authenticated users to read terminal data from tty0 for local users.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/06/2021
The vulnerability identified as CVE-2010-4176 represents a critical privilege escalation and information disclosure issue affecting system initialization processes in Fedora 13 and 14 distributions. This flaw exists within the plymouth-pretrigger.sh script that is part of the dracut and udev frameworks, which are essential components responsible for managing system boot processes and device handling during early system startup. The vulnerability stems from improper permission settings on the /dev/systty device file, creating a security boundary violation that allows authenticated remote attackers to gain access to terminal data from tty0, which is typically reserved for local user sessions and system console operations.
The technical implementation of this vulnerability involves the manipulation of device file permissions during the boot process execution. When the plymouth-pretrigger.sh script runs, it creates or modifies the /dev/systty device file with insufficiently restrictive permissions, typically allowing read access to users who are authenticated to the system. This creates a scenario where remote authenticated users can exploit the weak permissions to read terminal data that would normally be restricted to local users. The underlying issue demonstrates poor security hygiene in device file management during system initialization, where the principle of least privilege is violated by granting unnecessary access rights to system console devices.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to potentially gather sensitive information from terminal sessions that may contain passwords, system credentials, or other confidential data transmitted through the console interface. The vulnerability is particularly concerning because it operates during the early boot phase when system security controls are typically at their most critical and when the system is transitioning from initial boot to full operational state. This timing allows attackers to access data that may be used for further exploitation or to gain deeper insights into the system's operational environment. The weakness affects systems running Fedora 13 and 14 specifically, making it relevant to organizations that may still be operating legacy systems or have not fully migrated to more secure versions.
From a cybersecurity perspective, this vulnerability aligns with CWE-276, which describes improper file permissions, and represents a clear violation of access control principles. The attack vector follows patterns consistent with privilege escalation techniques described in the MITRE ATT&CK framework under the Privilege Escalation and Credential Access tactics. The vulnerability demonstrates how insecure initialization processes can create persistent security weaknesses that persist throughout system operation, making it a particularly dangerous class of flaw. Organizations should implement immediate mitigations including updating to patched versions of dracut and udev packages, reviewing and correcting device file permissions in system initialization scripts, and monitoring for unauthorized access to console devices. The vulnerability also underscores the importance of secure boot process implementation and proper permission management in system initialization frameworks, as highlighted in various security standards including NIST SP 800-53 and ISO 27001 controls related to system integrity and access control.