pam_http allows to authenticate via http request

PAM configuration example:
auth      required    pam_http.so   conf=/etc/pam_http.conf
account   required    pam_permit.so

pam_http.conf example:
auth_url = "http://api.myapp.com/user/login";
auth_method = "GET";
auth_username_field = "username";
auth_password_field = "password";
auth_timeout = 60;
auth_success_code = 200;

Enabling PAM debug:
Add the following line to /etc/syslog.conf
*.debug     /var/log/debug.log
service syslog restart