Unknown PAM message

[Sergio Tschá Wanderley]

I´m in trouble trying to figure out the meaning of the following message in /var/log/messages on my Red Hat 7.2 (kernel 2.4.7-10custom) server: Oct  8 06:37:46 server su(pam_unix)[17201]: session opened for user root by (uid=0) Oct  8 06:37:51 server su(pam_unix)[17201]: session closed for user root First I thought It was something related to a root login on the console or an user opening a root session but the message in that case wouldn´t be like this one. Notice the missing username after the "by" on the message.   I´m really don´t know where this came from. Thanks for any help Sergio Wanderley