Collecting data at a remote site requires that we remove it somehow – if we have a continuous connection, such as a reverse shell, then we can collect the data real time. However, if we deposit our mobile device with the intention of concealing it for an extended period of time, then we need to worry about a few issues as follows:
1. Preventing discovery of our collected data while on-site
2. Providing concealment during the duration of the event
3. Extracting the data safely
If we use mobile devices to collect and transmit data, we should be selective in our choices of devices and ensure that they are capable of encrypting any data at rest or in motion. Earlier models of most mobile devices are incapable of full disk encryption, which puts the device and us at risk if discovered and forensically examined; we, therefore, need to look for devices that will allow us to keep our
activities secret or provide a mechanism for covering our tracks if discovered.
Data at Rest
The newer mobile devices claim to provide something similar to full disk encryption. Although the ability of these devices to be able to protect data against forensic analysis is questionable, the devices are getting better at addressing the security of data at rest. We can do a few additional tasks to encrypt data at rest on our mobile devices to increase our comfort level about our hacking data.
Naturally, we cannot encrypt scripts that we need to run during our collection or attack phases; however, once we have collected the data, we can encrypt the data using strong passwords. The program gpg is one method of securing a file through symmetric encryption. It is possible to encrypt a file with the GNU Privacy Guard (GNU PG) application, which can be installed on a jailbroken iPod touch.
Mobile phones and personal data assistant (PDA) appliances used to be limited in their functionality; however, today there are wireless devices that operate using advanced operating systems and support applications that are incredibly useful for conducting clandestine activities. As an example, Apple’s iPod touch runs on the UNIX-Darwin kernel, which is open source,2 POSIX compliant, and single UNIX specification version 3 (SUSv3) compliant. Because of this, advanced hacker appli- cations can be built and installed onto the device, making the iPod touch a powerful hacking platform.
Regardless, there are some interesting trends that we can examine and use to our advantage.
The first trend is the use of open-source operating systems. As already mentioned, the iPod touch and the iPhone, both products of Apple Inc., uses the Darwin operating system. Additional proprietary applications, including graphic interface software, have been added to these portable devices; however, the core system is undeniably UNIX based.
The second trend is the increase in computing power and memory. Although the iPod touch does not have the processing capabilities of desktops or even laptops, they are quite capable of processing large amounts of data rapidly. As a benchmark test, the iPod touch (first generation) was able to process 577 MD5 hashes per second using the password cracking tool “John the Ripper.” In comparison, the MacBook Pro with a 2.8GHz Intel Core Duo processor was able to process 7674 per second. Although about one-twelfth the capability of the MacBook Pro, the iPod touch results are still impressive for what many consider as simply a fancy MP3 player.
The method of obtaining applications needed for penetration testing or covert audio and video communication will vary, depending on the mobile platform. In the case of the Droid and Palm Pre, access to the underlying operating system is avail- able by design. However, in the case of the iPod touch, access to the operating system can only be achieved by “jailbreaking” the phone, which circumvents protection mechanisms installed by Apple.
The actual method of jailbreaking varies, depending on the generation of the iPod touch and the version of the installed software (HOW TO jailbreak is explained in another post -same hack section). Once jailbroken, we can place applications on our device through different repositories – the most notable is called “Cydia.” More information on Cydia can be found at http://cydia.saurik.com/.