Steganography is the art of hidding a message in another common message. The hidden message can be clear text or encrypted and the container can be anything: image, music, single text or whatever…  The main benefit of steganography is that you can get the final message only if you know the technic used to hide it, because you’ll need to use the same algorithm. As a second layer of protection, you can also encrypt the data with any algorithm you like or with a private key.


With the evolution of cybercrime this last years, security is became an important budget in large companies. For instance, Facebook has created a dedicated platform for security reseacher and frequently reward them ($1.3 million spent in 2014).

Ebay, Airbnb, Yahoo, Snapchat, Wordpress, all of these companies are now aware about security and all of them have subscribed a bug bounty program.  Even mobile plateform as Android and IOS apps are recently focused by the giant Google.


As a pentester, you might be able to take control of systems that have a direct access but you also might be able to test the internal network and check the machine who are inside a subnetwork.

For that task you’ll have to use an already compromised machine as a bridge/gateway, this technic is called “pivot”. Depending of the context, different solutions exist to perform that task.


The easiest one. First you need to install Rinetd:

aptitude search rinetd
p   rinetd                                     - Internet TCP redirection server</pre>

Then edit the /etc/rinetd.conf file:

# bindadress    bindport  connectaddress  connectport    80   8080

Restart Rinetd and from now, all incoming traffic on on port 80 will be redirected to on port 8080. This can be usefull if a firewall is restricting outbound traffic on certain port.


The famous Offensive Security Certified Professional aka OSCP is the certification of the Penetration Testing with Kali Linux course aka PWK  provided by Offensive Security.

Offensive Security

Offensive Security is one the most active organization on the Internet about offsec. In addition to providing pentest and attack simulation services to their customers, they also bring a lot of great solution to the community.

Currently 6 online/live/in-house courses are available (pentest, wireless security, windows exploiation, web attacks…) who go with 5 different well known certifications. An incredible online virtual lab composed of intentionally vulnerable machine (ubuntu, XP, webapps, mail service, ftp vulns and so on…) has been created to enhance you security knowledge. Offensive Security is also editor of awesome projects such as Kali Linux, Metasploit and Google Hacking Database, the most used tools by pentesters.

The quality of all of these solutions is well recognized by the community and many companies and actually everyone who have to deals with offsec :)


Metadata are informations stored in a document itself but not easy to find for common mortals. Those infos usually are: file name/type/size, author, organization, created date, last modified date and so on… But sometimes there are extra infos that could be very interesting from a hacker point of view like email, phone number, username, geoloc and even local ip address.