CVE-2018-7191 Explained : Impact and Mitigation

The Linux kernel's tun subsystem, prior to version 4.13.14, contains a vulnerability that allows local users to trigger a denial of service by issuing a specific ioctl call.

Understanding CVE-2018-7191

This CVE relates to a vulnerability in the Linux kernel's tun subsystem that can lead to a denial of service attack.

What is CVE-2018-7191?

The Linux kernel's tun subsystem, before version 4.13.14, does not properly handle certain ioctl calls, leading to a denial of service vulnerability.

The Impact of CVE-2018-7191

This vulnerability allows local users to cause a denial of service, resulting in a NULL pointer dereference and system panic by issuing a specific ioctl(TUNSETIFF) call.

Technical Details of CVE-2018-7191

The technical aspects of the CVE-2018-7191 vulnerability.

Vulnerability Description

The Linux kernel's tun subsystem, before version 4.13.14, does not invoke the dev_get_valid_name function prior to register_netdevice, allowing local users to trigger a denial of service.

Affected Systems and Versions

Affected System: Linux kernel
Vulnerable Version: < 4.13.14

Exploitation Mechanism

Local users can exploit this vulnerability by issuing an ioctl(TUNSETIFF) call with a device name containing a forward slash (/) character.

Mitigation and Prevention

Ways to mitigate and prevent exploitation of CVE-2018-7191.

Immediate Steps to Take

Apply patches provided by the Linux kernel maintainers.
Monitor for any unusual system behavior that could indicate exploitation.

Long-Term Security Practices

Regularly update the Linux kernel to the latest version to ensure all security patches are applied.
Implement least privilege access controls to limit the impact of potential vulnerabilities.

Patching and Updates

Update the Linux kernel to version 4.13.14 or newer to mitigate the CVE-2018-7191 vulnerability.