CVE-2018-18386 Explained : Impact and Mitigation

In versions of the Linux kernel prior to 4.14.11, a vulnerability was found in the drivers/tty/n_tty.c file. This vulnerability can be exploited by local attackers who have access to pseudo terminals, allowing them to cause a halt or block further usage of any pseudo terminal devices. This vulnerability occurs due to confusion between the EXTPROC and ICANON features in the TIOCINQ function.

Understanding CVE-2018-18386

This CVE entry describes a vulnerability in the Linux kernel that could be leveraged by local attackers to disrupt the functionality of pseudo terminal devices.

What is CVE-2018-18386?

The CVE-2018-18386 vulnerability is a local security issue in the Linux kernel that affects versions prior to 4.14.11. It arises from a confusion between certain features in the TIOCINQ function, allowing attackers with access to pseudo terminals to interfere with their operation.

The Impact of CVE-2018-18386

The exploitation of this vulnerability could lead to a denial of service (DoS) situation where pseudo terminal devices become unresponsive or unusable, affecting system functionality and potentially causing disruptions.

Technical Details of CVE-2018-18386

This section provides more in-depth technical insights into the CVE-2018-18386 vulnerability.

Vulnerability Description

The vulnerability in drivers/tty/n_tty.c in the Linux kernel before 4.14.11 enables local attackers with pseudo terminal access to disrupt the operation of pseudo terminal devices due to confusion between EXTPROC and ICANON features in TIOCINQ.

Affected Systems and Versions

Affected Systems: Linux kernel versions prior to 4.14.11
Affected Components: drivers/tty/n_tty.c

Exploitation Mechanism

The vulnerability can be exploited by local attackers who have access to pseudo terminals, leveraging the confusion between EXTPROC and ICANON features in the TIOCINQ function to disrupt pseudo terminal device operations.

Mitigation and Prevention

Protecting systems from CVE-2018-18386 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update to Linux kernel version 4.14.11 or newer to mitigate the vulnerability.
Monitor and restrict access to pseudo terminals to prevent unauthorized exploitation.

Long-Term Security Practices

Implement the principle of least privilege to limit access to critical system components.
Regularly monitor and apply security patches to ensure system resilience against known vulnerabilities.
Conduct security training for users to raise awareness about potential risks and best practices.
Employ intrusion detection systems to detect and respond to suspicious activities.

Patching and Updates

Ensure timely patching of the Linux kernel to the latest version (4.14.11 or above) to address the CVE-2018-18386 vulnerability.