Vulnerability Discussion

Unrestricted usage of ptrace allows compromised binaries to run ptrace on other processes of the user. Like this, the attacker can steal sensitive information from the target processes (e.g., SSH sessions, web browser, etc.) without any additional assistance from the user (i.e., without resorting to phishing).

Check

Verify that OL 9 restricts usage of ptrace to descendant processes with the following commands:

$ sysctl kernel.yama.ptrace_scope
kernel.yama.ptrace_scope = 1

If the returned line does not have a value of "1", or a line is not returned, this is a finding.

Fix

Configure OL 9 to restrict usage of ptrace to descendant processes by adding the following line to "/etc/sysctl.d/99-sysctl.conf":

kernel.yama.ptrace_scope = 1

The system configuration files need to be reloaded for the changes to take effect. To reload the contents of the files, run the following command:

$ sudo sysctl --system