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Add a user that can gain root privileges in Ubuntu

Basic Linux No Responses »

Apr 212010

Add a user that can gain root privileges in Ubuntu

Answer:

You have created a user, and now you want to make this user (e.g. peter as an example) can gain root privileges.

Firstly, check your /etc/sudoers file

# sudo cat /etc/sudoers

You might found the following lines

# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL
john ALL=(ALL) ALL

Method 1

If you have the line %admin ALL=(ALL) ALL, then you can add the user (e.g peter) to the admin group using the command:

# sudo usermod -g admin peter

Method 2

Or you can edit the file /etc/sudoers to add your account manually

# sudo visudo

Append peter ALL=(ALL) ALL at the end..

%admin ALL=(ALL) ALL
john ALL=(ALL) ALL
peter ALL=(ALL) ALL

How to check failed login attempt in Ubuntu

Commands, Debian, Linux Security, Ubuntu No Responses »

Jan 312010

How to check failed login attempt in Ubuntu

Answer:

Every login attempts are logged in the file /var/log/auth.log in Ubuntu.

To check failed login attempt(s),

E.g.

# grep 'Failed password' /var/log/auth.log

Jan 31 14:00:27 localhost sshd[16141]: Failed password...
Jan 31 14:00:46 localhost sshd[16141]: Failed password...
Jan 31 14:00:49 localhost sshd[16141]: Failed password...

Disable AppArmor in Ubuntu

Linux Security, Ubuntu No Responses »

Jan 182010

Disable AppArmor in Ubuntu

Answer:

A lot of people don't like AppArmor and think it is too annoying, just like the SELinux, people sometimes want to disable it.

To do so:

# sudo invoke-rc.d apparmor stop
# sudo update-rc.d -f apparmor remove

Open a TCP port in Ubuntu’s ufw firewall

Linux Security, Ubuntu No Responses »

Jan 132010

Open a TCP port in Ubuntu's ufw firewall

Answer:

To open a TCP port, e.g. 8080 in the Ubuntu's UFW firewall (Uncomplicated firewall)

# sudo ufw allow 8080/tcp
# sudo ufw reload

How to generate random password?

Commands, Debian, Linux Security, Ubuntu No Responses »

Jan 022010

How to generate random password?

Answer:

Install the "makepasswd" package, for example, in Ubuntu, type

sudo apt-get install makepasswd

Then execute command

# makepasswd 

ShdDHNt7z

Or you can use another tool called pwgen

sudo apt-get install pwgen

and execute

# pwgen 8 10

It will generate 10 passwords with length equal to 8

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