I wanted to force root user to change password on next login , so I executed command
chage -d 0 root.
The command executed successfully and return code as 0.Even /etc/shadow file is showing changes properly as follow
root:$1$ZlexRZiM$3cb5GDF9s7.U0l/Xwoh0E1:0:1:90:7:::
Still system is not forcing root user to change password.I even tried to expire password by executing command
passwd -e root
still facing same issue.
IT is a very strange behavior, this should work since it is a rather standard way to do it.
What I would check is:
Full logout, don't test it with the "sudo -i" or "sudo su" to test it and perform a clean login as root (straight as root)
Check the /etc/login.defs file for variables settings (even if I don't think it is much probable). Variables you should check for are (pasting std fedora settings from my workstation):
PASS_MAX_DAYS 99999
PASS_MIN_DAYS 0
PASS_MIN_LEN 5
PASS_WARN_AGE 7
Related
I have the following bash script to restart the network manager in Debian. The script works as is it should, but not as I would like it to. When the script asks for the sudo password I am able to pass it along using echo, but it displays the password in terminal while the script executes, making it less asthetically pleasing than I would like. Is there anyway to have the script enter the password, but not display the password text while the script calls for the sudo password?
I have tried as many suggestions on Stack Overflow as i could find, well as Stack Exchange before submitting this question.
Script is as follows:
#!/bin/bash
clear
echo "Restarting service Network Manager"
echo""
sleep 1
echo -e "\033[0;31m......................................\033[0m"
echo -e "\033[0;31m......................................\033[0m"
sleep 1
echo""
sudo service network-manager restart
sleep 2
echo <Password>
sleep 2
echo "Service Network Manager Restarted"
sleep 1
echo ""
echo "Relinquishing control of terminal to user..."
sleep 7
clear
Remove the echo <Password> line? I am pretty sure it does nothing other than display the password, as sudo apparently (through an appropriate entry in /etc/sudoers) works without you having to give a password. (What you write to terminal with echo does not get passed to any other process.)
Generally speaking, you can use sudo -S to make sudo expect the password on stdin. But also generally speaking, if you have to hardcode a password in a script, you're doing it wrong in some way.
Is there anyway to have the script enter the password
Putting password in script is not a good idea. First, from security point of view, password may be recovered from script from anyone with access to script. Second, from maintenance view, once you change your password, scripts suddenly stop working and you have to update them all.
Fortunately, as you are already using sudo there is better solution. You can configure sudo to allow running certain command without password, by using NOPASSWD rule in /etc/sudoers.
myuser ALL=(ALL) NOPASSWD: service network-manager restart
See:
How do I run specific sudo commands without a password?
How to run a specific program as root without a password prompt?
Warning: Always edit /etc/sudoers with visudo, never directly. It prevents you from breaking /etc/sudoers. Once you break your /etc/sudoers, you won't be able to use sudo, including using sudo to fix /etc/sudoers.
try this /bin/echo -e "password\n" | sudo apt-get update
or see this Use sudo with password as parameter
So I have a strange issue which I'm pretty sure is SSH based.
If I ssh direct it works fine:
ssh user#domain <host>
If I then sudo to root this also works fine:
sudo su -
However If i subsequently su to a user from root it hangs for around 30-60 seconds then times out.
su - <user>
Eventually it does switch user. Likewise once I've su'd, if i exit my shell and go back up to root it will also hang.
Any ideas? There's nothing in /var/log/secure other than pam authentication messages.
Also I'm not sure whether "su" uses SSH under the hood? but I've noticed that rsync also has the same hanging issues and I do believe rsync DOES use SSH.
This is down to the AD authentication in PAM sss which was missing a little configuration in
/var/lib/sss/pubconf
Thanks for the suggestions anyway.
I have a VPS with Nagios installed, and I want to use Nagios to monitor the VPS resources in the /proc/user_beancounters file. The file has the following permissions:
-r-------- 1 root root 0 Oct 26 15:53 /proc/user_beancounters
So I downloaded the script from the Nagios Exchange:
https://exchange.nagios.org/directory/Plugins/Operating-Systems/*-Virtual-Environments/OpenVZ/check-beancounters/details
In the instructions it suggests to:
don’t forget to set the s-bit (chmod +s check_UBC.pl)
So, I copied the script over, and set the s-bit, then run it from the terminal as root. It works as expected. I then delete the temp file it created, su into the nagios user, and run the script. It works as expected. I delete the temp file it created, and start up Nagios. It can't read the /proc/user_beancounters file! The exact error I get, helpfully, is "could not read /proc/user_beancounters". This is, I believe, thrown by the line in the Perl script:
if (! open IN, "<", $UBC )
{
print "could not read $UBC\n";
exit $ERRORS{'CRITICAL'};
}
My OS is CentOS release 6.2 (Final).
My first thought is that it is some kind of SELinux voodoo, but there is no indication that SELinux is running on this server. Just in case, I tried the following:
echo 0 > /selinux/enforce
But this made no difference.
For reference, this is my nagios service running:
nagios 12939 0.0 0.0 203652 3404 ? Ssl 15:39 0:00 /usr/sbin/nagios -d /etc/nagios/nagios.cfg
And this is where I've put the Perl script:
-rwsr-sr-x 1 nagios nagios 2934 Oct 26 15:37 check_UBC.pl
Any suggestions as to what else I can try?
PS apologies if this should go in a different SE site - never sure with questions that involve scripts, permissions etc...
UPDATE 1
I created a shell script to see if I could 'emulate' the nagios service. It is extremely simple:
#!/bin/bash
/usr/lib64/nagios/plugins/check_UBC.pl
And now I have the following permissions:
-rwsr-sr-x 1 root root 2934 Oct 26 15:37 check_UBC.pl
-rwxrwxrwx 1 root root 51 Oct 26 19:29 check_UBC.sh
As root:
[root#/usr/lib64/nagios/plugins]$ ./check_UBC.pl
everything is fine..
[root#/usr/lib64/nagios/plugins]$ ./check_UBC.sh
everything is fine..
As nagios:
-bash-4.1$ ./check_UBC.pl
everything is fine..
-bash-4.1$ ./check_UBC.sh
everything is fine..
So still no clue...
UPDATE 2
My nagios command definition:
define command{
command_name check_beancounters
command_line $USER1$/check_UBC.pl
}
And the service definition:
define service{
use local-service
host_name localhost
service_description VPS Beancounters
check_command check_beancounters
}
UPDATE 3
I managed to get it to work, but am not over the moon about giving the nagios user full sudo access with no password. In /etc/sudoers I put this on the last line:
nagios ALL=(ALL:ALL) NOPASSWD: ALL
And then changed my command definition to:
define command{
command_name check_beancounters
command_line sudo $USER1$/check_UBC.pl
}
Apparently recent versions of linux will not respect the +s permission when running an interpreted script, only a binary. So I guess I will have to compile a binary wrapper for the script?
UPDATE 4
As per Joe Young's suggestion, I changed my visudo entry to:
nagios ALL=NOPASSWD: /usr/lib64/nagios/plugins/check_UBC.pl
Which hopefully is relatively harmless!
Try changing the owner of check_UBC.pl to root so that when nagios executes check_UBC.pl the script runs as setuid of it's owner root and not the nagios user.
chown root:root check_UBC.pl
EDIT:
Can you post your command definition that's calling check_UBC.pl?
The last thing I can think of to try is to install the perl-suid module: https://chrisjean.com/fix-setuid-cannot-exec-sperl/
Although, if check_UBC.pl runs from the command line with no problem, I'm not sure what difference it would make.
What would the risk be to change the permissions on /proc/user_beancounters to 444 (read for all?) It only contains a number, correct? Not sure if that particular file "sticks around" after a reboot, or worse, constantly gets replaced as the services are running, so this could be a problem still.
Also, consider trying to test for actual "existence" of the file, before you attempt to read from it. Since we're in /proc directory, things do change, from time to time....
Lastly, you are asking to open the file, but syntactically is it asking to open in a read only mode? You may want to try a system call to simply "cat" the file contents, in your shell script, and see if you get a response.
I would like to know if there is anyway to send a mail as soon as someone tries su -, su or su root. I know the mail command and I am trying to write a script but I am very confused as to
where to write it - whether in .bashrc of root or in /etc/process
how to invoke the mail on the use of su
I've tried the usual Google search etc. but got links on usage of su, disabling it, securing ssh etc - none of which answered this question.
Thanks in advance
I guess that your underlying requirement is that you have a bunch of people you have given root privilege to but you don't completely trust them so you want to keep an eye on them. Your solution to this is to get yourself sent mail whenever they become root.
The problem with this solution is that the root user has unlimited privilege and so there's nothing to stop them from counteracting this mechanism. They could for instance, edit the /etc/login.defs file in one session, do the good thing that you want them to do and then later su to root and do the bad thing that you fear and at the end of that session they edit the /etc/login.defs file back to it's original state and you're none the wiser. Alternatively they could just make a copy of /usr/bin/bash and make the copy a suid file that will give them privilege whenever they run it.
You might be able to close any of the vulnerabilities I've just suggested but there will be many, many more. So you either trust them or else don't use su at all and give them sudo permission to run just those commands that they need to do the thing you want them to do.
There's a log file called /var/log/secure which receives an entry any time su is executed. It gets entries under other conditions as well. It's described in the Linux Administrator's Security Guide.
If user "fred" executes su -, an entry will appear which looks something like this:
Jul 27 08:57:41 MyPC su: pam_unix(su-l:session): session opened for user root by fred(uid=500)
A similar entry would appear with su or su root.
So you could set up a script which monitors /var/log/secure as follows:
#!/bin/sh
while inotifywait -e modify /var/log/secure; do
if tail -n1 /var/log/secure | grep " su: "; then
tail -n1 /var/log/secure | grep " su: " | mail -s "su occurred" you#email.com
fi
done
Note that you need to have the inotify-tool package installed to use inotifywait.
If this script is running in the background, it should send an email to you#email.com any time an su entry occurs.
Now where to run the script. One approach would be to put this into an executable script file (say, watchsu) and call it from your rc.local file:
nohup /path/to/watchsu 2>&1 &
I'm sure there are other ideas for where to start it. I'm not familiar with CentOS.
According to the man page for su, in /etc/login.defs you can set either SULOG_FILE file or SYSLOG_SU_ENABLE yes to log all su activity. Then you just need something like inotifywait to watch the log file for su events.
I usually have to login in 20 to 50 times daily as a super user, typing the long password again and again..
i have just created a simple bash script
#!/bin/bash
sudo -s
echo password
./test
output root#localhost:
password
when i execute it, it works like charm... but it shows my password on the screen.....
do some one have any other best solution...... for this small problem.......
i hope this is not all the solution in security standard...... can we have any other solution with out exposing my password.....
You can pipe the echo'd password into a command. Try something like this:
echo myPassword | sudo -S
You can see come more info on this here.
Question is, do you REALLY want your password in a shell script file? (just emphasizing that its a terrible idea)
Is there a reason that you can't sudo su - to just become the root user instead of prepending all of your commands with sudo blah?
just change ownership of the script to root & set SUID-Bit in user the permissions
chmod u=rws g+x o+x script123
the script will run as root for every user
You can configure sudo to require a password only every so many minutes. The default is 5 minutes. Read the sudoers man page and scroll down to this:
timestamp_timeout
Number of minutes that can elapse before sudo will ask
for a passwd again. The timeout may include a
fractional component if minute granularity is
insufficient, for example 2.5. The default is 5. Set
this to 0 to always prompt for a password. If set to a
value less than 0 the user's timestamp will never
expire. This can be used to allow users to create or
delete their own timestamps via sudo -v and sudo -k
respectively.
simple solution is to use key base authentication
Use ssh-copy-id instead following from this tutorial which is secure