The Comprehensive Mobile Ethical Hacking Course. Mobile devices introduce new threats to organizations through untrusted applications. Therefore, it has become a mandate to evaluate and identify flaws regularly and conduct penetration tests to avoid any mishaps and losses.

Mobile security, or more specifically mobile device security, is the protection of smartphones, tablets, and laptops from threats associated with wireless computing.^[1] It has become increasingly important in mobile computing. Of particular concern is the security of personal and business information now stored on smartphones.

More and more users and businesses use smartphones to communicate, but also to plan and organize their users’ work and also private life. Within companies, these technologies are causing profound changes in the organization of information systems and therefore they have become the source of new risks. Indeed, smartphones collect and compile an increasing amount of sensitive information to which access must be controlled to protect the privacy of the user and the intellectual property of the company.

All smartphones, as computers, are preferred targets of attacks. This is because these devices have family photos, pictures of pets, passwords, and more. For attackers, these items are a digital passport to access everything they would need to know about a person. This is why attacks on mobile devices are on the rise. ^[2]These attacks exploit weaknesses inherent in smartphones that can come from the communication mode—like Short Message Service (SMS, aka text messaging), Multimedia Messaging Service (MMS), WiFi, Bluetooth and GSM, the de facto global standard for mobile communications. There are also exploits that target software vulnerabilities in the browser or operating system while some malicious software relies on the weak knowledge of an average user.

Security countermeasures are being developed and applied to smartphones, from security in different layers of software to the dissemination of information to end users. There are good practices to be observed at all levels, from design to use, through the development of operating systems, software layers, and downloadable apps.

Attack based on SMS and MMS

Some attacks derive from flaws in the management of SMS and MMS.

Some mobile phone models have problems in managing binary SMS messages. It is possible, by sending an ill-formed block, to cause the phone to restart, leading to the denial of service attacks. If a user with a Siemens S55 received a text message containing a Chinese character, it would lead to a denial of service.^[17] In another case, while the standard requires that the maximum size of a Nokia Mail address is 32 characters, some Nokia phones did not verify this standard, so if a user enters an email address over 32 characters, that leads to complete dysfunction of the e-mail handler and puts it out of commission. This attack is called “curse of silence”. A study on the safety of the SMS infrastructure revealed that SMS messages sent from the Internet can be used to perform a distributed denial of service (DDoS) attack against the mobile telecommunications infrastructure of a big city. The attack exploits the delays in the delivery of messages to overload the network.

Another potential attack could begin with a phone that sends an MMS to other phones, with an attachment. This attachment is infected with a virus. Upon receipt of the MMS, the user can choose to open the attachment. If it is opened, the phone is infected, and the virus sends an MMS with an infected attachment to all the contacts in the address book. There is a real-world example of this attack: the virus Commwarrior^[16] uses the address book and sends MMS messages including an infected file to recipients. A user installs the software, as received via MMS message. Then, the virus began to send messages to recipients taken from the address book.

Attacks based on communication networks

The attacker may try to break the encryption of the mobile network. The GSM network encryption algorithms belong to the family of algorithms called A5. Due to the policy of security through obscurity it has not been possible to openly test the robustness of these algorithms. There were originally two variants of the algorithm: A5/1 and A5/2 (stream ciphers), where the former was designed to be relatively strong, and the latter was designed to be weak on purpose to allow easy cryptanalysis and eavesdropping. ETSI forced some countries (typically outside Europe) to use A5/2. Since the encryption algorithm was made public, it was proved it was possible to break the encryption: A5/2 could be broken on the fly, and A5/1 in about 6 hours .^[18] In July 2007, the 3GPP approved a change request to prohibit the implementation of A5/2 in any new mobile phones, which means that it has been decommissioned and is no longer implemented in mobile phones. Stronger public algorithms have been added to the GSM standard, the A5/3 and A5/4 (Block ciphers), otherwise known as KASUMI or UEA1^[19] published by the ETSI. If the network does not support A5/1, or any other A5 algorithm implemented by the phone, then the base station can specify A5/0 which is the null algorithm, whereby the radio traffic is sent unencrypted. Even in case mobile phones are able to use 3G or 4G which have much stronger encryption than 2G GSM, the base station can downgrade the radio communication to 2G GSM and specify A5/0 (no encryption) .^[20] This is the basis for eavesdropping attacks on mobile radio networks using a fake base station commonly called an IMSI catcher.

In addition, tracing of mobile terminals is difficult since each time the mobile terminal is accessing or being accessed by the network, a new temporary identity (TMSI) is allocated to the mobile terminal. The TMSI is used as the identity of the mobile terminal the next time it accesses the network. The TMSI is sent to the mobile terminal in encrypted messages.

Once the encryption algorithm of GSM is broken, the attacker can intercept all unencrypted communications made by the victim’s smartphone.

Attacks based on Wi-Fi

An attacker can try to eavesdrop on Wi-Fi communications to derive information (e.g. username, password). This type of attack is not unique to smartphones, but they are very vulnerable to these attacks because very often the Wi-Fi is the only means of communication they have to access the internet. The security of wireless networks (WLAN) is thus an important subject. Initially, wireless networks were secured by WEP keys. The weakness of WEP is a short encryption key which is the same for all connected clients. In addition, several reductions in the search space of the keys have been found by researchers. Now, most wireless networks are protected by the WPA security protocol. WPA is based on the “Temporal Key Integrity Protocol (TKIP)” which was designed to allow migration from WEP to WPA on the equipment already deployed. The major improvements in security are the dynamic encryption keys. For small networks, the WPA is a “pre-shared key” which is based on a shared key. Encryption can be vulnerable if the length of the shared key is short. With limited opportunities for input (i.e. only the numeric keypad), mobile phone users might define short encryption keys that contain only numbers. This increases the likelihood that an attacker succeeds with a brute-force attack. The successor to WPA, called WPA2, is supposed to be safe enough to withstand a brute force attack. Free Wi-Fi is usually provided by organizations such as airports, coffee shops, and restaurants for a number of reasons. In addition to spending more time on the premises, Wi-Fi access helps them to stay productive.^[1] It’s likely they’ll end up spending more money if they spend more time on the premises. Enhancing customer tracking is another reason. A lot of restaurants and coffee shops compile data about their customers so they can target advertisements directly to their devices. This means that customers know what services the facility provides. Generally, individuals filter business premises based on Internet connections as another reason to gain a competitive edge. The ability to access free and fast Wi-Fi gives a business an edge over those who do not. Network security is the responsibility of the organizations. There are numerous risks associated with their unsecured Wi-Fi networks, however. The man-in-the-middle attack entails the interception and modification of data between parties. Additionally, malware can be distributed via the free Wi-Fi network and hackers can exploit software vulnerabilities to smuggle malware onto connected devices. It is also possible to eavesdrop and sniff Wifi signals using special software and devices, capturing login credentials and hijacking accounts.^[10]

As with GSM, if the attacker succeeds in breaking the identification key, it will be possible to attack not only the phone but also the entire network it is connected to.

Many smartphones for wireless LANs remember they are already connected, and this mechanism prevents the user from having to re-identify with each connection. However, an attacker could create a WIFI access point twin with the same parameters and characteristics as the real network. Using the fact that some smartphones remember the networks, they could confuse the two networks and connect to the network of the attacker who can intercept data if it does not transmit its data in encrypted form.^[21][22]

Lasco is a worm that initially infects a remote device using the SIS file format.^[23] SIS file format (Software Installation Script) is a script file that can be executed by the system without user interaction. The smartphone thus believes the file to come from a trusted source and downloads it, infecting the machine.^[23]

Principle of Bluetooth-based attacks

Security issues related to Bluetooth on mobile devices have been studied and have shown numerous problems on different phones. One easy to exploit vulnerability: unregistered services do not require authentication, and vulnerable applications have a virtual serial port used to control the phone. An attacker only needed to connect to the port to take full control of the device.^[24] Another example: a phone must be within reach and Bluetooth in discovery mode. The attacker sends a file via Bluetooth. If the recipient accepts, a virus is transmitted. For example: Cabir is a worm that spreads via Bluetooth connection.^[16] The worm searches for nearby phones with Bluetooth in discoverable mode and sends itself to the target device. The user must accept the incoming file and install the program. After installing, the worm infects the machine.

Attacks based on vulnerabilities in software applications

Other attacks are based on flaws in the OS or applications on the phone.

Web browser

The mobile web browser is an emerging attack vector for mobile devices. Just as common Web browsers, mobile web browsers are extended from pure web navigation with widgets and plug-ins, or are completely native mobile browsers.

Jailbreaking the iPhone with firmware 1.1.1 was based entirely on vulnerabilities on the web browser.^[25] As a result, the exploitation of the vulnerability described here underlines the importance of the Web browser as an attack vector for mobile devices. In this case, there was a vulnerability based on a stack-based buffer overflow in a library used by the web browser (Libtiff).

A vulnerability in the web browser for Android was discovered in October 2008.^[26] As the iPhone vulnerability above, it was due to an obsolete and vulnerable library. A significant difference with the iPhone vulnerability was Android’s sandboxing architecture which limited the effects of this vulnerability to the Web browser process.

Smartphones are also victims of classic piracy related to the web: phishing, malicious websites, software that run in the background, etc. The big difference is that smartphones do not yet have strong antivirus software available.^[2]

The internet offers numerous interactive features that ensure a higher engagement rate, capture more and relevant data, and increase brand loyalty. Blogs, forums, social networks, and wikis are some of the most common interactive websites. Due to the tremendous growth of the internet, there has been a rapid rise in the number of security breaches experienced by individuals and businesses over the past few years. Users can balance the need to utilize the interactive features while also maintaining caution regarding security issues in several ways.^[27] Reviewing computer security regularly and correcting, upgrading, and replacing the necessary features are a few of the ways to do this. Installation of antivirus and anti-spyware programs is the most effective way of protecting the computer, and they offer protection against malware, spyware, and viruses. As well, they use firewalls, which are typically installed between the internet and the computer network in order to find a balance. By acting as a web server, the firewall prevents external users from accessing the internal computer system. Also, secure passwords and not sharing them help maintain the balance.^[28]

Operating system

Sometimes it is possible to overcome the security safeguards by modifying the operating system itself. As real-world examples, this section covers the manipulation of firmware and malicious signature certificates. These attacks are difficult.

In 2004, vulnerabilities in virtual machines running on certain devices were revealed. It was possible to bypass the bytecode verifier and access the native underlying operating system.^[3] The results of this research were not published in detail. The firmware security of Nokia’s Symbian Platform Security Architecture (PSA) is based on a central configuration file called SWIPolicy. In 2008 it was possible to manipulate the Nokia firmware before it is installed, and in fact in some downloadable versions of it, this file was human-readable, so it was possible to modify and change the image of the firmware.^[29] This vulnerability has been solved by an update from Nokia.

In theory, smartphones have an advantage over hard drives since the OS files are in ROM, and cannot be changed by malware. However, in some systems it was possible to circumvent this: in the Symbian OS it was possible to overwrite a file with a file of the same name.^[29] On the Windows OS, it was possible to change a pointer from a general configuration file to an editable file.

When an application is installed, the signing of this application is verified by a series of certificates. One can create a valid signature without using a valid certificate and add it to the list.^[30] In the Symbian OS all certificates are in the directory: c:\resource\swicertstore\dat. With firmware changes explained above it is very easy to insert a seemingly valid but malicious certificate.

Attacks based on hardware vulnerabilities

Electromagnetic Waveforms

In 2015, researchers at the French government agency Agence nationale de la sécurité des systèmes d’information (ANSSI) demonstrated the capability to trigger the voice interface of certain smartphones remotely by using “specific electromagnetic waveforms”.^[5] The exploit took advantage of antenna-properties of headphone wires while plugged into the audio-output jacks of the vulnerable smartphones and effectively spoofed audio input to inject commands via the audio interface.^[5]

Juice Jacking[

Juice Jacking is a physical or hardware vulnerability specific to mobile platforms. Utilizing the dual purpose of the USB charge port, many devices have been susceptible to having data exfiltrated from, or malware installed onto a mobile device by utilizing malicious charging kiosks set up in public places or hidden in normal charge adapters.

Jail-breaking and rooting

Jail-breaking is also a physical access vulnerability, in which mobile device users initiate to hack into the devices to unlock it, and exploit weaknesses in the operating system. Mobile device users take control of their own device by jail-breaking it, and customize the interface by installing applications, change system settings that are not allowed on the devices. Thus, allowing to tweak the mobile devices operating systems processes, run programs in the background, thus devices are being expose to variety of malicious attack that can lead to compromise important private data.^[4]

Password cracking

In 2010, researcher from the University of Pennsylvania investigated the possibility of cracking a device’s password through a smudge attack (literally imaging the finger smudges on the screen to discern the user’s password).^[27] The researchers were able to discern the device password up to 68% of the time under certain conditions.^[27] Outsiders may perform over-the-shoulder on victims, such as watching specific keystrokes or pattern gestures, to unlock device password or passcode.

Malicious software (malware)

As smartphones are a permanent point of access to the internet (mostly on), they can be compromised as easily as computers with malware. A malware is a computer program that aims to harm the system in which it resides. Mobile malware variants have increased by 54% in the year 2017.^[31] Trojans, worms and viruses are all considered malware. A Trojan is a program that is on the smartphone and allows external users to connect discreetly. A worm is a program that reproduces on multiple computers across a network. A virus is malicious software designed to spread to other computers by inserting itself into legitimate programs and running programs in parallel. However, it must be said that the malware are far less numerous and important to smartphones as they are to computers.