A website hosted in Plesk fails to load: ModSecurity: Response body too large

[Suhitha]

Question: A website hosted in Plesk fails to load: ModSecurity: Response body too large


Applicable to:

• Plesk for Linux

Symptoms

• A website is not loading with the following error message in a web browser:

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500
Internal Server Error

• The following messages are logged in Domains > example.com > Logs:

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[error] [client 203.0.113.2] ModSecurity: Output filter: Response body too large (over limit of 524288, total not specified). [hostname "www.example.com"] [uri "/index.php"] ...

Cause

The website has exceeded default ModSecurity SecResponseBodyLimit parameter (1 MB).


Resolution

Adjusting 'SecResponseBodyLimit' for one domain

1.Log in to Plesk.

2.Go to Domains > example.com > Hosting & DNS > Apache & nginx Settings.

3.Add the line below to Additional directives for HTTP and Additional directives for HTTPS fields to increase SecResponseBodyLimit to 256 MB (or define your own value):

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<IfModule mod_security2.c>
    SecResponseBodyLimit 268435456
</IfModule>
4.Apply the changes.


Adjusting 'SecResponseBodyLimit' for all domains
 

1.Log in to Plesk.

2.Go to Tools & settings > Web Application Firewall (ModSecurity) > Settings tab. > Custom directives section:

3.Add the line below to Custom directives section to increase SecResponseBodyLimit to 256 MB (or define your own value):

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SecResponseBodyLimit 268435456
4.Apply the changes.