TOSS 5 must restrict usage of ptrace to descendant processes.

Unrestricted usage of ptrace allows compromised binaries to run ptrace on other processes of the user. This way, 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).

Verify TOSS 5 restricts usage of ptrace to descendant processes using the following command:

$ sudo 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.

Configure TOSS 5 to restrict using ptrace to descendant processes by adding the following line to a file, in the "/etc/sysctl.d" directory:

kernel.yama.ptrace_scope = 1

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

$ sudo sysctl --system