ConfigServer Security & Firewall (CSF) LiteSpeed Configuration

If you're using ConfigServer Security & Firewall (CSF), you have to make a few changes to the CSF configuration. This guide will explain the various changes that need to be done!

In LiteSpeed Web Server version 5.3.6, we moved /tmp/lshttpd/.rtreport to /dev/shm to decrease disk IO. As a result, we introduced a symlink from the original location so any existing configuration doesn't break.

However, this can cause alerts from CSF/LFD such as this:

Time:   Wed Feb 13 06:05:29 2019 +0100
File:   /tmp/lshttpd/.rtreport
Reason: Suspicious symlink (->/dev/shm/lsws/lshttpd/status/.rtreport)
Owner:  nobody:nobody (99:99)
Action: No action taken

Add /tmp/lshttpd/\.rtreport.* to /etc/csf/csf.fignore to suppress this alert, and then restart CSF using csf -ra.

Depending on your settings, or the amount of traffic your customers receive, you can easily end up with lsphp processes that run for a long time. This happens because we spawn a parent lsphp process for each vhost or customer. This process is used for a few things including shared memory for opcache and keeping the process alive for faster traffic handling (we skip the startup delay).

However, this can trigger some LFD alerts such as the one below:

Time:         Tue Feb 12 16:33:02 2019 +0100
Account:      XXXXXXXX
Resource:     Process Time
Exceeded:     64846 > 43200 (seconds)
Executable:   /opt/cpanel/ea-php56/root/usr/bin/lsphp
Command Line: lsphp                                  
PID:          14899 (Parent PID:14899)
Killed:       No

We can prevent this by adding pexe:/opt/cpanel/ea-php.*/root/usr/bin/lsphp.* to /etc/csf/csf.pignore, and then restarting CSF using csf -ra.

The lshttpd binary is unknown to LFD, so you may also receive alerts like this:

Time:    Tue Feb 12 19:03:40 2019 +0100
PID:     13751 (Parent PID:13739)
Account: nobody
Uptime:  21627 seconds

Executable:
/usr/local/lsws/bin/lshttpd.5.3.1

Command Line (often faked in exploits):
litespeed (lshttpd - #01)

Network connections by the process (if any):
tcp: xx.xx.xx.xx:80 -> xx.xx.xx.xx:4007

We can prevent this by adding pexe:/usr/local/lsws/bin/lshttpd.* to /etc/csf/csf.pignore, and then restarting CSF using csf -ra.

If you're using QUIC, then make sure to open up port UDP 443 on your firewall. This can be done in CSF under UDP_IN and UDP_OUT. You can read more about enabling QUIC here.