I am planning to use the below the Authen PAM script( Example from the CPAN site) from mod_perl

Will the username,password we supply can be monitored on the server using ps -ef command?

Via ps - but not necessarily with the -ef options, more likely with ps axe (BSD style) - they will only be visible if they are exported into the environment (i.e. somehow accessible inside the perl script through the %ENV hash). But there are other methods to intercept them on a server, e.g. sniffing the network or tracing the apache process.

update - be aware also, that changing authentication tokens will only succeed if the process doing that runs under UID 0, that is, as root.

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