Cover your tracks

On Linux

/etc/syslog.conf

In this file you can read all the logs that syslog log.

On linux systems a lot of logs are stored in:

/var/logs

For example:

/var/log/messages

Here you have failed and successful login attempts. SSH, SUDO, and much more.

/var/log/auth.log

/var/log/apache2/access.log
/var/log/apache2/error.log

Remove your own ip like this

grep -v '<src-ip-address>' /path/to/access_log > a && mv a /path/to/access_log

What it does is simply to copy all lines except the lines that contain your IP-address. And then move them, and them move them back again.

grep -v <entry-to-remove> <logfile> > /tmp/a ; mv /tmp/a <logfile> ; rm -f /tmp/a

These logs are not stored in plaintext but instead as binaries. Which makes it a bit harder to clear.

who

last

lastlog

All your commands are also stored.

echo $HISTFILE
echo $HISTSIZE

You can set your file-size like this to zero, to avoid storing commands.

export HISTSIZE=0

If you set it when you get shell you won't have to worry about cleaning up the history.

Shredding files lets you remove files in a more secure way.

shred -zu filename