csf CloudLinux Disable ptrace error tips

Ptrace block

Starting with kernel 3.10.0-427.18.s2.lve1.4.21 ( CloudLinux 7) and 2.6.32-673.26.1.lve1.4.17 ( CloudLinux 6) we re-implemented ptrace block to protect against ptrace family of vulnerabilities. It prevents end user from using any ptrace related functionality, including such commands as strace, lsof or gdb .

By default, CloudLinux doesn’t prevent ptrace functionality.


kernel.user_ptrace = 1
kernel.user_ptrace_self = 1

The option kernel.user_ptrace disables PTRACE_ATTACH functionality, option kernel.user_ptrace_self disables PTRACE_TRACEME .

To disable all ptrace functionality change both sysctl options to 0, add this section to /etc/sysctl.conf :

## CL. Disable ptrace for users
kernel.user_ptrace = 0
kernel.user_ptrace_self = 0

Apply changes with:

$ sysctl -p