Mobile Device Security

Vol. 9 Special Edition

Robert Thibadeau, Ph.D., is Senior Vice President and Chief Scientist at Wave Systems, an adjunct professor in the School of Computer Science at Carnegie Mellon (teaching computer security since 1996), and a contributing author on encryption to the ABA book titled Data Breach and Encryption Handbook (2011). He can be reached at Lucy L. Thomson is principal of Livingston PLLC, a Washington, DC, law firm (which focuses on law and technology, particularly cybersecurity and global data privacy), Chair of the ABA Section of Science & Technology Law, and editor of the Data Breach and Encryption Handbook (2011). She can be reached at

As the use of mobile devices explodes around the globe,1 concerns about the security of data and communications on mobile devices are increasing. Data breaches are occurring with alarming frequency throughout the mobile device environment, in all industry sectors, among all types of companies large and small, and among governments around the globe.2 In 2012 through mid-2013, the loss or theft of 132 mobile devices resulted in exposure of more than 2,680,000 personal records.

In addition to personal records, security failures related to mobile devices have also exposed confidential communications, intellectual property, and other sensitive business information. The harm to individuals and organizations can be extensive, including fraud, identity theft, and a multiplicity of breakdowns in data protection such as data theft, privacy violations, and spying. As mobile devices are increasingly employed for payments and electronic health records, theft of money, goods, services, and the most sensitive personal health records will become more frequent.

Of particular concern for lawyers are the large volumes of sensitive and confidential data they increasingly store on their mobile devices— information subject to the attorney-client privilege; client trade secrets; records that are sealed or under a protective order; classified data; grand jury records; and many other types of sensitive data, including personal, financial, health care, and law enforcement records. As the use of mobile devices continues to grow, the likelihood of breaches involving such data becomes more certain.

Lawyers have a responsibility to make sure that the mobile devices they use for confidential communications are secure.3 At the same time, lawyers should counsel their clients regarding the need to adopt security best practices throughout their organizations. As information becomes the primary means of production, and institutions forge ahead to adopt sweeping changes based on mobile technologies, the risks underlying this mobile transformation are legion and not well understood. All of these developments have profound implications for the law.

Some mobile breaches are the result of vulnerabilities in the design and configuration of mobile devices. In other cases, hackers have inserted malware (malicious code) into applications (apps) so when users download them onto mobile devices, the malware allows hackers to gain access to sensitive information. Some malware can subvert search results and redirect users to a web page where they are encouraged to download additional malware, while other malware can cause users’ personal information to be publicly disclosed without their knowledge. Hackers can intercept unencrypted data as it is transmitted to and from mobile devices. The vulnerabilities are particularly serious if the mobile devices are used to communicate with legal clients by email or through social media, or to view, process, or store confidential data and information.

Mobile Device Security

Computer security technology is fundamentally about “information isolation” and the controls over access to that information. A common example of an information isolation mechanism is the user name and password typically used for logging in, but any modern operating system such as Windows, iOS, or Android has literally hundreds of thousands of fine-grained access controls in every copy. These controls are set by policies, and security fails when policy-governed isolation fails.

To effectively seal the cracks between technology and law, it would be better if there were some minimal isolation guarantees that could be uniformly assumed by the laws. These are ultimately the subject of policies set by manufacturers, application providers (app providers), telephone companies (telcos), IT managers (IT), and personal good practices. To fully appreciate how so much can go wrong in mobile device security, it is important to understand the fundamental classes of security defects (attack surfaces) and what security measures already exist to mitigate them. These attack surfaces encompass the device itself, the operating system (OS) on the device, and external service providers such as app providers, telcos, and IT.

Figure 1 (below) shows how security architects categorize defects in the mobile device ecosystem. This approach can help in determining who did what in a potential negligence case.



For each attack surface, the diagram provides examples of attack vectors with some of the common attacks on, or other failures of, generally accepted good security policy. The device may be stolen, the data on it may be stolen, and various sensors such as cameras and microphones may be surreptitiously turned on. The OS itself may be faulty (as illustrated in the FTC-HTC case discussed below), preboot Trojans (malware that affects preboot operations) may “jail break”4 the OS protections, or the OS may permit weak passwords. Provider failures include failure of IT management (policies to manage mobile devices remotely, as discussed below), as well as malicious app injection and data theft (as in the FTC’s Frostwire case). These are only a few of the hundreds of failures that can occur across these attack surfaces.

App Vulnerabilities

The huge ecosystem of apps—well over 1.5 million and growing—creates additional security issues that differ from those involving the security architecture of mobile devices and OS themselves.5 Many of the apps are made available through official stores or markets, such as the Apple iTunes store, some Android markets, and the Microsoft Store, where strict controls are exercised to help ensure that the apps do not violate accepted security practices. Apps are also available through unofficial sources, particularly in the Android world.

Malicious apps are often attack vectors that pierce the device, OS, and provider attack surfaces depicted in Figure 1. They create causal event paths that memorialize an actual attack or security failure and show where culpability lies.

For example, the FBI recently issued a warning about malware that attacks Android OS for mobile devices and lures users to compromise their mobile devices.6 For example:

  • Loozfon malware contains advertisements for work opportunities with a link to a website designed to push the malware to a user’s mobile device; once on the mobile device, the malicious software uses an OS weakness to steal contact details from the user’s address book.
  • FinFisher malware can take over the components of a mobile device and remotely control and monitor it. The malware is transmitted to a smartphone when the user visits a specific web link or opens a text message masquerading as a system update.

A company that provides security protection analyzed more than 400,000 apps (60 percent) in Android’s official Google Play marketplace (as of September 2012) and classified 25 percent of the apps as “suspicious” or “questionable,” based on the permissions requested, categorization of the app, user rating, number of downloads, and reputation of the publisher.7 The report concluded that Android’s open framework has made it the primary target of hackers, who lure unsuspecting users to download their apps and end up exposing the users’ organizations to significant security risks.

Legal Issues

As mobile devices become essential for individual communication and global ecommerce, sensitive data and information must be protected. Two cases involving the security of mobile devices and apps have already been brought by the US Federal Trade Commission (FTC).

In one case settled by the FTC (as announced on February 22, 2013), the FTC had charged that millions of Android smartphones were manufactured by HTC America (a leading mobile device manufacturer) with insufficient security controls, which compromised sensitive device functionality, potentially permitting malicious applications to send text messages, record audio, and even install additional malware onto a consumer’s device, all without the user’s knowledge or consent. The FTC alleged that malware placed on consumers’ devices without their permission could be used to record and transmit information entered into or stored on the device, including, for example, financial account numbers and related access codes or medical information. Malicious applications could also gain unauthorized access to a variety of other sensitive information, such as a user’s geolocation information and the contents of a user’s text messages. The complaint also alleged that HTC America failed to provide its engineering staff with adequate security training, review or test the software on its mobile devices for potential security vulnerabilities, follow well-known and commonly accepted secure coding practices, and establish a process for receiving and addressing vulnerability reports from third parties.8

In 2011, the FTC charged that an app developer, FrostWire LLC, had engaged in unfair and deceptive practices by: (1) configuring the default settings of a peer-to-peer (P2P)9 file-sharing app so that it publicly exposed, upon installation and set-up on the user’s smartphone or tablet, a wide range of personal information (including photos, videos, documents, and other files) without the user’s authorization; and (2) misleading users about the extent to which downloaded files would be distributed with the P2P file-sharing network. On October 11, 2011, it was announced that Frostwire had agreed to settle FTC charges that its software (e.g., FrostWire for Android) likely would cause consumers unwittingly to expose sensitive personal files stored on their mobile devices, and that it misled consumers about which downloaded files from their desktop and laptop computers would be shared with a file-sharing network. The settlement bars Frostwire from using default settings that share consumers’ files, requires it to provide free upgrades to correct the unintended sharing, and bars misrepresentations about what files its applications will share.10

Mobile Security Standard

The legal standard for mobile security increasingly needs careful examination. Although only a handful of judicial decisions specifically address the issue of information security, other key cases set forth relevant principles when assessing security practices and possible negligence by organizations that fail to implement appropriate security and subsequently suffer a security breach.

Recall the well-known T.J. Hooper case11 in which two tugboats were ruled unseaworthy and liable for damages to the cargo because they did not have radio receivers to receive storm warnings. The T.J. Hooper case held that a boat can be deemed unseaworthy if it is not equipped with a well-known, generally accepted practice of ensuring safety—in that case, a radio. Similarly, smartphones and tablets need to be deemed worthy of use, particularly when proper security is already widely available today and best practice standards exist that can make mobile devices quite secure against many possible attacks.

The foreseeability of a potential harm is also a key factor. Nash v Port Auth. of N.Y. & N.J.12 discusses this issue in the context of the 1993 terrorist truck bombing of the World Trade Center (WTC). In this case, experts had warned that the public garage under the WTC posed a security risk, but the landlord had failed to take steps to address that risk. In a lawsuit and trial following the bombing, the jury found that the defendant Port Authority was negligent. In affirming the case on appeal, the court discussed the standard of reasonable care and stated: “there are circumstances in which the nature and likelihood of a foreseeable security breach and its consequences will require heightened precautions [above minimal precautions].”

The duty to reasonably secure a mobile device or network against foreseeable intrusions (e.g., a hacker attack) depends on the nature of the risk as well as the burden of minimizing the risk. An enforceable duty can be found under the common law (negligence, breach of contract, breach of fiduciary duty, etc.) and in state statutes, such as consumer protection and data security laws (e.g., Massachusetts, Nevada, Maryland, and New Jersey include a duty to provide information security to protect personal information).13

In the case of a breach, questions would be asked about whether the organization potentially responsible for securing the device (e.g., the manufacturer of the device, OS developer, provider, or user) took reasonable steps to minimize the risk—e.g., whether it conducted a risk assessment, determined the likelihood of a breach, and assessed the adequacy of the security that was adopted. Based on such a risk assessment, appropriate security controls should then be selected, implemented, and continuously monitored so that risks and vulnerabilities are reduced to a reasonable and appropriate level.

What Steps Must Be Taken to Provide Appropriate Security for Mobile Devices?

Developing a plan for appropriate security begins with a risk assessment. The purpose of the risk assessment is to inform decision makers and support risk responses by identifying:

  1. relevant threats to the organization, or threats directed through other organizations against them, via the mobile device;
  2. vulnerabilities of the mobile device both internal and external to the organization;
  3. impact (i.e., harm) to the organization that may occur given the potential for threats exploiting vulnerabilities; and
  4. likelihood that harm will occur.

The end result is a determination of risk, which is typically a function of the degree of harm and the likelihood of harm occurring.

Participants who use mobile devices for key transactions, or to process or store sensitive and confidential information, should take reasonable steps to minimize the risks. To prevent data breaches, it is essential to analyze and understand the root causes of security failures and develop a specific plan to address them.

Security Architecture

The security architecture for modern mobile devices, which all have the same main properties, is strong. If the security architecture is implemented and managed properly, many potential threats will be eliminated. The remaining threats are insider attacks and the failure of users to follow good security practices.

Security Policy

The vast majority of attacks and security failures are due to failed security policies. The good news is that organizations can nearly eliminate breaches of mobile devices if they take a prioritized approach that adopts and enforces good security practices.

Information security policy is an aggregate of directives, rules, and practices that prescribes how an organization manages, protects, and distributes information.14 It is particularly important for organizations to adopt security policies that let users know the expectations for the use of their mobile devices and the rules they must follow to keep their information systems secure. Security policy should address the fundamentals of the organization’s governance structure, including:

  • information security roles and responsibilities;
  • statement of security controls baseline and rules for exceeding the baseline; and
  • rules of behavior that users are expected to follow and consequences for noncompliance.

It is important that organizations adopt a “culture of security” in which all employees and business/outsourcing partners consider themselves responsible for the security of the organization.

Basic policies must be enforced and should require strong passwords and require encryption of data, permit remote locate/wipe capability, and limit apps that can be put on the phone. User security education is equally critical—when installing apps, many users routinely click “yes” without considering the nature of the permissions they are granting. Hackers exploit this lack of awareness by building malware that exploits the permissions the user has given, creating easy access for them to steal data from mobile devices.

Furthermore, the use of mobile devices does not occur in a vacuum. Although sensitive data such as authentication credentials (user names and passwords), client email, encryption keys, contacts, and so on are often stored directly on a mobile device, such data and information may also be transmitted to the cloud after being created or processed on a mobile device. Use of a cloud provider introduces further security and privacy risks that must be addressed.15


How mobile devices are configured and used affects the security of sensitive data just as much as the security technology on the devices. With so many mobile devices on networks today, participants in the mobile device ecosystem must adopt and enforce effective security policies and procedures that protect sensitive and confidential data and other information the organization creates, collects, stores, and transmits on mobile devices. The failure to secure sensitive data can expose an organization to unacceptable risks and result in enormous liability in the event of a breach.


Protect Your Mobile Device and Data

FBI Recommendations

  • When purchasing a smartphone, know the features of the device, including the default settings. Turn off unnecessary features to minimize the attack surface of the device.
  • Depending on the type of phone, the OS may offer encryption, which can be used to protect the user’s personal data in case of loss or theft.
  • Consult reviews of the developer/company who published the app.
  • Review and understand the permissions you are giving when you download apps.
  • Passcode protect your mobile device, and enable the screen lock feature after a few minutes of inactivity. This is the first layer of physical security to protect the contents of the device.
  • Obtain malware protection for your mobile device. Look for applications that specialize in antivirus or file integrity to help protect your device from rogue applications and malware.
  • Be aware of applications that enable geolocation, which will track the user’s location anywhere and can be used for marketing and by malicious actors (e.g., stalkers and/or burglars).
  • Jail break or rooting is used to remove certain restrictions imposed by the device manufacturer or cell phone carrier and allows the user nearly unregulated control over what programs can be installed and how the device can be used. At the same time, however, jail breaking often involves exploiting significant security vulnerabilities and increases the attack surface of the device. Any time an application or service runs in “unrestricted” or “system” level within an OS, it allows any compromise to take full control of the device.
  • Do not allow your device to connect to unknown wireless networks, which could be rogue access points that capture information passed between your device and a legitimate server.
  • If you decide to sell your device or trade it in, make sure you wipe the device (reset it to factory default) to avoid leaving personal data on the device.
  • Smartphones require updates to run applications and firmware; without these, the risk of the device being hacked or compromised increases.
  • Avoid clicking on or otherwise downloading software or links from unknown sources.
  • Use the same procedures on your mobile phone as you would on your computer when using the Internet.



1. Mobile devices are the fastest-growing computing technology. As of 2012, 87% of American adults owned a cell phone, 45% owned a smartphone, and 31% owned a tablet. By the end of 2013, the number of mobile-connected devices will exceed the number of people on earth, and by 2017 it is expected that there will be nearly 1.4 mobile devices per capita. Pew Research Center (Washington, D.C. 2013), available at February/Pew-Internet-Mobile.aspx.

2. Identity Theft Resource Center (ITRC),

3. The Model Ethics 20/20 Rules adopted by the American Bar Association (2012) explicitly require that lawyers provide “competent representation” by keeping abreast of changes in the law and its practice, including the “benefits and risks associated with relevant technology” (Rule 1.1). To protect the confidentiality of information, a lawyer shall make “reasonable efforts to prevent the inadvertent or unauthorized disclosure of, or unauthorized access to, information relating to the representation of a client” (Rule 1.6).

4. Jail breaking entails installing software on a phone to “break open” the phone’s OS security and allow a user to modify anything it protects, including limits on apps that can be loaded on the device. This is a well-known form of “privilege escalation” that usurps OS isolation assumptions and thus weakens the device’s security.

5. As of October 2012, the apps available for Android phones and for Apple mobile devices numbered about 700,000 each, while Microsoft had 120,000 apps. Shara Tibken, “Google Ties Apple with 700,000 Android Apps” (10/30/12), available at

6. Smartphone Users Should Be Aware of Malware Targeting Mobile Devices and Safety Measures to Help Avoid Compromise (Oct. 12, 2012), available at

7. Bit9 Report, Pausing Google Play: More Than 100,000 Android Apps May Pose Security Risks With Mobile Security Survey, available at

8. See the complaint and settlement agreement at

9. P2P enables computers to form a network and share digital files (music, video, and documents), play games, and facilitate online telephone conversations such as Skype directly with other computers on the network.

10. See the complaint and settlement agreement at

11. 60 F .2d 737 (2d Cir. 1932).

12. 51 A.D.3d 337, 856 N.Y.S.2d 583 (2008).

13. See Arthur E. Peabody, Jr. and Renee A. Abbott, The Aftermath of Data Breaches: Potential Liability and Damages, in Data Breach and Encryption Handbook (2011), chapter 3.

14. See Information Security Handbook: A Guide for Managers, NIST SP 800-100 (2007), available at

15. See Guidelines on Security and Privacy in Public Cloud Computing, NIST SP 800-144 (2011).


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