Mastering Linux Security and Hardening - Second Edition

Preventing users from seeing each others' processes

By default, users can use a utility such as ps or top to see everyone else's processes, as well as their own. To demonstrate this, let's look at the following partial output from a ps aux command:

[donnie@localhost ~]$ ps auxUSER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMANDroot         1  0.0  0.7 179124 13752 ?        Ss   12:05   0:03 /usr/lib/systemd/systemd --switched-root --system --deserialize 17root         2  0.0  0.0      0     0 ?        S    12:05   0:00 [kthreadd]root         3  0.0  0.0      0     0 ?        I<   12:05   0:00 [rcu_gp]. . .. . .colord 2218 0.0 0.5 323948 10344 ? Ssl 12:06 0:00 /usr/libexec/colordgdm 2237 0.0 0.2 206588 5612 tty1 Sl 12:06 0:00 /usr/libexec/ibus-engine-simpleroot 2286 0.0 0.6 482928 11932 ? Sl 12:06 0:00 gdm-session-worker ...