Solved

postfix log file question

Posted on 2007-04-02
3
265 Views
Last Modified: 2013-12-15
I am running FC4 running postfix when i check the log files i get this:
Apr  2 01:11:02 mail2 su(pam_unix)[19952]: session opened for user dennis by (uid=0)
Apr  2 01:11:02 mail2 su(pam_unix)[19952]: session closed for user dennis
Apr  2 01:11:02 mail2 su(pam_unix)[19955]: session opened for user dennis by (uid=0)
Apr  2 01:11:02 mail2 su(pam_unix)[19955]: session closed for user dennis
Apr  2 01:11:02 mail2 su(pam_unix)[19958]: session opened for user dennis by (uid=0)
Apr  2 01:11:02 mail2 su(pam_unix)[19958]: session closed for user dennis
Apr  2 01:11:02 mail2 su(pam_unix)[19961]: session opened for user dennis by (uid=0)
Apr  2 01:11:02 mail2 su(pam_unix)[19961]: session closed for user dennis
Apr  2 01:11:02 mail2 su(pam_unix)[19964]: session opened for user dennis by (uid=0)
Apr  2 01:11:02 mail2 su(pam_unix)[19964]: session closed for user dennis
Apr  2 01:39:02 mail2 su(pam_unix)[20083]: session opened for user paul by (uid=0)
Apr  2 01:39:02 mail2 su(pam_unix)[20083]: session closed for user paul
Apr  2 01:39:02 mail2 su(pam_unix)[20086]: session opened for user paul by (uid=0)
Apr  2 01:39:02 mail2 su(pam_unix)[20086]: session closed for user paul
Apr  2 01:39:02 mail2 su(pam_unix)[20089]: session opened for user paul by (uid=0)
Apr  2 01:39:02 mail2 su(pam_unix)[20089]: session closed for user paul
Apr  2 01:39:02 mail2 su(pam_unix)[20092]: session opened for user paul by (uid=0)
Apr  2 01:39:02 mail2 su(pam_unix)[20092]: session closed for user paul
Apr  2 01:39:02 mail2 su(pam_unix)[20095]: session opened for user paul by (uid=0)
Apr  2 01:39:02 mail2 su(pam_unix)[20095]: session closed for user paul
Apr  2 03:44:01 mail2 su(pam_unix)[20622]: session opened for user billy by (uid=0)
Apr  2 03:44:01 mail2 su(pam_unix)[20622]: session closed for user billy
Apr  2 03:44:01 mail2 su(pam_unix)[20625]: session opened for user billyt by (uid=0)
Apr  2 03:44:02 mail2 su(pam_unix)[20625]: session closed for user billy
Apr  2 03:44:02 mail2 su(pam_unix)[20628]: session opened for user billy by (uid=0)
Apr  2 03:44:02 mail2 su(pam_unix)[20628]: session closed for user billy
Apr  2 03:44:02 mail2 su(pam_unix)[20631]: session opened for user billy by (uid=0)
Apr  2 03:44:02 mail2 su(pam_unix)[20631]: session closed for user billy
Apr  2 03:44:02 mail2 su(pam_unix)[20634]: session opened for user billy by (uid=0)
Apr  2 03:44:02 mail2 su(pam_unix)[20634]: session closed for user billy
Apr  2 03:44:02 mail2 su(pam_unix)[20637]: session opened for user billy by (uid=0)
Apr  2 03:44:02 mail2 su(pam_unix)[20637]: session closed for user billy

is this just postfix cycling thru the users?  

also i was wondering about creating a new root account named dennis  and then disabling the root account how do i do that?
0
Comment
Question by:knightdogs
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 27

Accepted Solution

by:
Nopius earned 500 total points
ID: 18841354
> is this just postfix cycling thru the users?  
No. These logs come from 'su' command executed by root to become different users: 'billy', 'paul' and 'dennis'. Why it was executed - I don't know.

> also i was wondering about creating a new root account named dennis  and then disabling the root account how do i do that?
Do you mean you need to change user name 'root' to 'denis'?
I don't recommend but it's the simplest way to do so: edit files '/etc/passwd' and /etc/shadow and change user name 'root' to 'denis'. But most system scripts that rely on username 'root' for superuser will fail.
Another approach is to use selinux, but it's too complex and it works only for FC5 and above.
Third possible way - is also to change /etc/passwd but for user 'denis' change uid and gid fields to 0, he become your second root user. Also not recommended.
0
 

Author Comment

by:knightdogs
ID: 18842895
I am sorry for not being more clear.  i ran rkhunter and it said that root can be logged in to and that was a secrutiy concern.  i thought if i created another account like root, named dennis, and then disabled root that would fix it.  i saw a site 2 weeks ago that got hacked and it showed root uid 0   bla  bla  bla  and i figured that the hacker finally guessed roots password and took over so if i removed roots account i would slow them down, am i wrong?
0
 
LVL 27

Expert Comment

by:Nopius
ID: 18886073
knightdogs, thanks for points.

> figured that the hacker finally guessed roots password and took over so if i removed roots account i would slow them down, am i wrong?
You are wrong. System becomes unmanageble without root account.

Disallowing root to perform _remote_ login be done in /etc/ssh/sshd_config, with option 'PermitRootLogin No'. However really good security measure to prevent password guessing is a strong enouth root password (with, suppose, 10 randomly generated characters, not a dictionary word, with catipal/small letters and with digits).

Disallowing root FTP login is also possible, depends on your system, how to do it.
Disallowing any protocol (ftp, telnet, pop3 without apop/tls) with cleartext password is also a good preventive measure.
0

Featured Post

[Webinar] Learn How Hackers Steal Your Credentials

Do You Know How Hackers Steal Your Credentials? Join us and Skyport Systems to learn how hackers steal your credentials and why Active Directory must be secure to stop them. Thursday, July 13, 2017 10:00 A.M. PDT

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In the first part of this tutorial we will cover the prerequisites for installing SQL Server vNext on Linux.
Liquid Web and Plesk discuss how to simplify server management with a single tool  in their webinar.
Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, Just open a new email message.  In the To field, type your recipient's fax number @efaxsend.com. You can even send a secure international fax — just include t…
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question