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Tuesday 17 August 2010

Other useful linux commands - act 3

iwconfig - check wireless setup

dmesg - query a USB device, plug it in a type this command

lspci - chipset interrogation

lsusb - as above

Configure Open SSH securely

Modify config in /etc/ssh or ssh_config to disable support for legacy protocols. Look for the 'Protocol 2,1' line and remove the ver 1 protocol.
Also set 'PermitRootLogin no' and 'MaxAuthTries 3'


After the changes have been made run:
service ssh restart

View attack activity by looking at /var/log/auth. If you see a particular IP that keeps attacking, put an entry in /etc/hosts.deny

You can automate this process by installing the DenyHosts package. Edit it's config in /etc/denyhosts.conf and change DENY_THRESHOLD_INVALID from 5 to 2

Enhanced GUI nmap

Try Zenmap, usually in your distros repository

Quick port scan of a machine

nmap

Not installed by default on Ubuntu or Mint, use:

sudo apt-get install nmap

Change hostname in linux

Using suitable privelages, navigate to /etc and edit the following files, replacing the default name with your desired machine name. Prefereably the FQDN.

/etc/hosts
/etc/hostname