GUI editor to tame mod_security rules

⌈⌋ branch:  modseccfg



Select a vhost/conf

Select which config file will be shown and edited through the vhost/conf dropdown:


This will change the status icons shown next to the rules, if anything is configured in that vhost/conf file.


And Disable or Enable will influence that very rule state. Browse for high error counts to check on rules which might be false positives. Verify what the rules do with the Info dialog.


Take particular note to the recent log entries there. Recent events will give a clue if a rule really blocked concrete intrusion attempts, or expected requests.

Select log file to show

Switching vhosts should automatically select the according log file. Else use the dropdown box:


For rule scoring it's best to use the error.log. Audit.logs take much longer to process. (In particular non-JSON audit logs, or reading concurrent/directory-stored ones.) Browse through the entries to see more detail in the logview box:


Use the search feature above the log dropdown to filter events by common messages.

See also LogReports / Preprocessors


A handful of common log errors are explained via LogAdvise


  • There's a few packages/scripts in FileInstall
  • Any entry will bring up a "terminal" prompt before excuting the commands.
  • Notably the installation will work on remote servers. If you want to apply the same package locally, you might need to restart modseccfg without remoting.



There's a few notable options for modseccfg itself, that change default behaviours and even how config files are updated.

  • Most notably the backup options (albeit there are failsafes, it's still beta software).
  • Or where to mount remote filesystems.
  • And how to filter logs.


This dialog updates core mod_security directives. Most of those you want to change in the global mod_security.conf (selected as vhost/conf), or a customized /www/etc/security.conf if you have such.

But you can of course change these directives on a per-vhost basis. Most notably SecRuleEngine to DetectionOnly whilst testing the rules.

Note that each option will yield a lengthier tooltip explanation.

FileCoreRuleSet options

The CoreRuleSet comes with its own set of runtime variables (tx.varname). Generally you want to edit the crs-setup.conf file globally, if possible.

Some vhosts might need customized handling however. And this is where it gets complicated. You will need preconf enabled. And keep in mind that you'll be preempting setvar: expressions from crs-setup.conf. Which is why the dialog offers an "id" and a "fn" option atop.
When overriding variables, the according entry from crs-setup needs to be stopped from running (because it's executed after the *.preconf rule). Hence the CRS options dialog will usually use id:5999 and a ctl:removeRule= list for each variable.

However, when invoking the dialog on a freshly created preconf file, all the usual fields will be empty. That's ok for boolean and numberic flags, which are quick to fill in. But the tx.allowed_request_content_types for example requires appending on the original list.

  • So, you either want to use an text editor in parallel for the long fields,
  • Or temporarily enable Settings → CRS options → use defaults to have them filled with standard values.
  • Or select the global crs-setup.conf as vhost/conf first, then start the CRS options dialog, and set "id" to 5999 and "fn" to the vhost.*.preconf file you actually want to update.

So the dialog is more of a gimmick here. Editing crs-setup.conf directly is often more practical, unless there are stark contrasts between vhosts.


See also recipe on other/conditional SecRule* constructs to control rules.


F4 will bring up the .conf file editor. Because some things are best handled with a keyboard after all.

And F3 will show the editor (in read-only mode) for the current log file instead.

Modify dialog

see modify


  • vhost.png [download] added by mario on 2020-12-09 09:39:31. [details]
  • state.png [download] added by mario on 2020-12-09 09:39:24. [details]
  • settings.png [download] added by mario on 2020-12-09 09:39:15. [details]
  • logview.png [download] added by mario on 2020-12-09 09:39:04. [details]
  • logfilter.png [download] added by mario on 2020-12-09 09:38:56. [details]
  • log.png [download] added by mario on 2020-12-09 09:38:48. [details]
  • info.png [download] added by mario on 2020-12-09 09:38:39. [details]