Vulnerability Discussion

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors.

A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.

When the kernel invokes systemd-coredumpt to handle a core dump, it runs in privileged mode, and will connect to the socket created by the systemd-coredump.socket unit. This, in turn, will spawn an unprivileged systemd-coredump@.service instance to process the core dump.

Check

Verify RHEL 8 is not configured to acquire, save, or process core dumps with the following command:

$ sudo systemctl status systemd-coredump.socket

systemd-coredump.socket
Loaded: masked (Reason: Unit systemd-coredump.socket is masked.)
Active: inactive (dead)

If the "systemd-coredump.socket" is loaded and not masked and the need for core dumps is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix

Configure the system to disable the systemd-coredump.socket with the following commands:

$ sudo systemctl disable --now systemd-coredump.socket

$ sudo systemctl mask systemd-coredump.socket

Created symlink /etc/systemd/system/systemd-coredump.socket -> /dev/null

Reload the daemon for this change to take effect.

$ sudo systemctl daemon-reload