International Journal of Interactive Mobile Technologies (iJIM) – eISSN: 1865-7923 – Vol. 15, No. 03, 2021 Paper—Penetration Test for the 3G Internet Service Provider and Free Basics Service by Facebook Penetration Test for the 3G Internet Service Provider and Free Basics Service by Facebook https://doi.org/10.3991/ijim.v15i03.18905 Salim M. Zaki Dijlah University College, Baghdad, Iraq salimzki@gmail.com Abstract—The number of devices connected to the Internet via mobile de- vices is increasing every day. The cost of mobile data over 3G and 4G networks is high in some countries, which pushes many users to browse the internet through text-only service. Facebook proposed a free basics service that allows users to browse Facebook for free but without showing images. This research formats the images on web pages using a method that transfers images over text-only networks. This will allow users with low income or slow connections to surf text service over the internet with images supported. The main objective is to test the free basics service by Facebook and Internet Service Provider over 3G networks, additionally proposing an image format for text-only networks. The proposed algorithm converts .png and .jpg images and posts them on the Facebook page. The results from the Facebook page show images that can be seen over 3G networks with the free mode enabled. Keywords—Facebook, penetration test, mobile data, social network security 1 Introduction Social networks are becoming an essential part of people’s everyday life [1]. Social networks’ platforms increase with the number of users and offer different services to those users. However, this comes at a cost to privacy and security, and, therefore, se- curing mobile applications and social networks is vitally important in the development process [2]. Facebook founded the Internet.org organization [3] with Free Basics service in col- laboration with cell phone service suppliers in several developing nations [4] [5]. The concept of the Digital Divide [6] and Internet.org sets a goal for customers of 3G or 4G networks to be able to access many web benefits on their cell phone programs without subscribing to paid internet service. The service has expanded to more than 60 countries across Asia, Africa, and South and Central America, with 25 new coun- tries included last year. Facebook claims that its objective with Free Basics is to con- nect more individuals to the internet, with an end goal to control the computerized gap between people and web services [7] [8] [3]. Images are an attractive element of any web page, which leads to the desire to find a way to allow people to browse images on a text-only service as users demand images with good or high resolution [9]. 4 http://www.i-jim.org https://doi.org/10.3991/ijim.v15i03.18905 Paper—Penetration Test for the 3G Internet Service Provider and Free Basics Service by Facebook The motivation behind this study is to check the ability of text-only services to ac- cept special images and continue showing those images to users. Privacy on social media is a vital topic nowadays due to large amounts of private data exchanged over social media platforms such as Facebook [10] [11]. This study aims to test the quality of Free Basics service as few research studies have tested the quality and the ability to bypass the limitations of text-only service. Although there are research studies focus- ing on Free Basics Service by Facebook such as [12] [13] [14] [15], to the best of our knowledge, there has been no research on a penetration test for free basics services. Additionally, this research is in the scope of “bug bounty,” which is a program that rewards experts for finding software bugs in websites, apps and services [16][17]. Therefore, this study provides a technique for posting images to Facebook and down- loading them as .png files over free modes on 3G networks. The major contributions of the paper are summarized as follows: 1. Developing an algorithm that provides images for text-only networks. 2. Images can be seen on Facebook pages even when enabled via a free mode. 3. Testing the free basics service provided by Facebook and Internet Service provider (ISP) over 3G. 2 Background 2.1 What is the service architecture of free basics? As shown in Fig. 1, the Free Basics administration includes three autonomous ser- vice suppliers: (I) the cellular company that agrees to convey information for any Free Basics administration at no expense to the end client. (II) Proxy servers by Facebook to manage free basics services. (III) the service provided by participants in the service such as Wikipedia and Facebook social media site. Fig. 1. Architecture of Free Basics Service by Facebook iJIM ‒ Vol. 15, No. 03, 2021 5 Paper—Penetration Test for the 3G Internet Service Provider and Free Basics Service by Facebook 2.2 Image file format Files provide the vital mechanism for storing, archiving and exchanging image da- ta. And the choice of the correct file format is an important decision. Today, there exists a wide range of standardized file formats, and developers can always find at least one image format suitable for their applications [18] [19]. The selection of file format is not an easy choice, but there are criteria in place to choose the correct format for the application: • Type of Image File: Includes binary image, color image, greyscale and special im- ages. • Size on Disk and Compression Technique: One important factor is maximum size of the image. The storage requirement of an image file plays an important role in selecting the appropriate image file format for an application. The compression technique and lossy or lossless is important. • Compatibility and Domain: Image file format compatibility is vital when used in global application of place such as internet or archive. The file format should achieve this factor by choosing the best format that is compatible in different do- mains such as web browsers and file viewing and editing software. Table 1 offers a comparison of the most commonly used image file formats on the internet, mobile devices and personal computers. Tagged Image File Format is suita- ble for archiving but not supported on the web; on the other hand, Graphics Inter- change Format is supported on the web, but with low resolution. The suitable solution is Portable Network Graphics with good resolution and a size that is suitable for web design. The Joint Photographic Experts Group became very popular among users and designers due to its good features such as resolution and size [20] [19]. Table 1. Summary of Image File Format Features Image Format Extension Good Features Shortcomings Application Tagged Image File Format tif, tiff • Storing raster graphics imag- es. • Widely used for different applications. No wide support in web browsers. Scanning, word processing, optical character recogni- tion. Graphics Inter- change Format gif • Wide support on web. • Static and dynamic. • Portability on many operating systems. Low resolution and poor colors. Widely used on web and operating sys- tems. Portable Network Graphics png • Widely used on Internet. • Multi-color support. • Alpha channel for transparen- cy. No dynamic image in one file as is the case in GIF for- mat. Web design. Joint Photo- graphic Experts Group jpg, jpeg • Most widely used image format. • Good resolution and colors. Not well suited for line drawings and other textual or iconic graphics. Digital photog- raphy, Internet and social media. 6 http://www.i-jim.org https://en.wikipedia.org/wiki/Image_scanner https://en.wikipedia.org/wiki/Word_processor https://en.wikipedia.org/wiki/Word_processor https://en.wikipedia.org/wiki/Optical_character_recognition https://en.wikipedia.org/wiki/Optical_character_recognition https://en.wikipedia.org/wiki/Optical_character_recognition Paper—Penetration Test for the 3G Internet Service Provider and Free Basics Service by Facebook 2.3 Data URIs and inline images For images and SVG files, the number of HTTP requests can be decreased instead of downloading a separate file of the image file; the image data can be represented in a format that can be included inside HTML5 or CSS code [21][22]. Encoding image data in a string format is done with Base64 encoding. Base64 is a collection of comparable binary-to-text encoding structures that represent binary data in an American Standard Code for Information Interchange (ASCII) string format by translating it into a radix-64 format. Base64 encoding schemes are used to encode binary data to be stored and transferred over media that are designed to deal with ASCII. This is to guarantee that the data is intact without amendment during the transmission process. A number of applications use Base64 such as email using MIME, and storing composite data in XML [22][23]. The type of data to be encoded is specified first in format of Data URI, such as im- age/png; the base64 means base-64 encoding. If the base64 is lost, standard URL en- coding is used instead. An example of Base64 encoding in an image tag of HTML: