Knowledge base
SuExec: what it is and how it affects your scripts
What is SuExec?
For apache’s official explanation: http://httpd.apache.org/docs/suexec.html.
For a friendlier version, SuExec is a security option: all processes on a machine run as a user. Normally with cgi/perl scripts, the user used is nobody, with SuExec however, the user becomes you. SuExec allows the script to run as you and access files as you could if you were to access the files directly from FTP. When SuExec is not enabled, you would have to give world writable/readable permissions on files which isn’t safe as that would mean anyone’s script on the same server would be able to read/write to that file. SuExec enabled means that scripts can only access and manipulate the specific user’s files, not someone else’s.
How does this affect your CGI/Perl scripts?
Many of your script’s instructions will tell you to change permissions on directories the script needs to write to, to 777 (drwxrwxrwx) and files to 777 (_rwxrwxrwx) or 666 (_rw_rw_rw_). SuExec will not let scripts run or access files that have those permissions or are in directories with those permissions, as they are insecure.
Instead, any time a script tells you to change permissions to that, make the permissions for the file or directory to 755 (_rwxr_xr_x), and not what the instructions say to. Most instructions for cgi and perl scripts are made for those people on servers not running SuExec, but since you are, you have to do things like permissions a little differently.
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- File permissions explained
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- Formmail: important notes
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- SuExec: what it is and how it affects your scripts