The Evolution of Mobile Phone Evidence

The Evolution of Mobile Phone Evidence

From Best Guess to Precise Prediction, a Science Emerges

By Daren M Greener CEng BSc CITP MBCS.
Principal Consultant, SYTECH – Digital Forensics.

 

Synopsis

The integration of the mobile phone has seamlessly interwoven itself into many aspects of everyday life with inbuilt and associated technologies that made it the must have device it is today.

 

This article provides a general review to the evolution of mobile phone evidence and in particular Cell-Site Analysis, highlighting how technological and sociological change has brought about a maturity to its application whilst litigation attitudes to this branch of digital forensics have not always kept pace.

 

Cell-Site Analysis (movement and location) is one of the fundamental components in a trident of mobile telecommunication evidence that also includes Attribution (who operated a particular phone) and Communications Analysis (who interacts with who and at what level).

Cell-Site Analysis Trident
Cell-Site Analysis Trident

 

Background – What is Cell-Site Analysis?

Cell-Site Analysis is a discipline of digital forensics that essentially examines the historic location and movement of mobile phones based upon record of the wireless link used to transfer call-events between ‘the network’ and mobile phone device (handset).

 

Each mobile phone network provider (Vodafone, O2, EE, etc.) maintains a network of transceivers (transmitter & receiver) throughout the country in distribution of service coverage/provision.

 

Many of these transceivers (cell-masts) are now common place and widely recognised for what they are standing like sentinels adjourning motorway networks or as great skeletal leviathans on high vantage points. Many more surreptitiously blend into the background of our surroundings, hidden on rooftops or disguised as street furniture such as lampposts, flagpoles and occasional modern artwork.

Cell-Site Analysis Masts
Cell-Site Analysis Masts

Typical Cell-Mast structures and antenna equipment

 

Importantly though, each network transceiver (cell-site) is uniquely identifiable. Therefore, the service provision from each transceiver is traceable and quantifiable with regards to the area of service cover.

 

As the mobile phone networks have grown and expanded over time, then the number and diversity of transceivers (cell-sites) has increased dramatically with the resulting coverage areas becoming ever more localised (smaller) to cope with greater capacity demands.

 

 

The Popularity of Mobile Phone Evidence.

As the adoption of the mobile phone infiltrated into society, towards the end of the 1990’s, it brought about a frequent source of information within criminal investigations that could, amongst other things, indicate the general movement and location of a suspect(s). Additionally, this evidential record of movement and activity could in turn be compared against a suspect’s account or alibi when such was offered.

 

  • In essence, the mobile phone represented, and continues to be, a personal tracking device.

 

Never before had law enforcement/forensic science had access to such a recorded stream of reference points that could indicate, without witness, a person’s general movements along with a  record of who they had been in contact with over a prescribed period of time.

 

Previously, such evidence would be reliant on fingerprinting or a possible DNA trace at a specific location – subject to the close scrutiny required to find such evidence. There was a greater reliance upon witnesses or informants to provide information with regards to a suspect’s whereabouts.

 

The introduction of electronic banking services during the mid-1980’s had been a catalyst to early electronic activity tracking. The introduction of the Automated Teller Machine (ATM / cash point) in 1985 was followed by the arrival of the debit card in 1987 and both provided a limited source of information when tracking a person’s location or movements in accordance with their purchasing/financial activity.

 

For law enforcement the adoption of the mobile phone has been akin to having a string of eye-witnesses or informants all pointing in sequence to the area of a suspect. ‘He’s over here, he’s over there, he went that way and no he wasn’t over there.’

 

In the early stages Cell-Site Analysis was often applied to define where a person (and their phone) could not have been to support or refute an alibi or allegation.

 

A suspect may have stated that they had spent an evening at home whilst their corresponding Cell-Site activity may have contradicted such assertion and demonstrate widespread movements and activity.

 

Predominantly mobile phone evidence often provides the glue to bring other evidence into sequence.  It acts like fly-paper attracting and sticking other items of evidential value – eye witness accounts, DNA recovery, CCTV footage, ANPR sightings and payment transactions etc – into a pattern of chronological consistency.

 

  • The greater the level of transaction within the mobile phone records the stronger the bond of the glue.

 

A Note on Attribution

A crucial aspect to the value of obtainable evidence is the attribution of the mobile phone to a particular person. Attribution applies both in terms of phone ownership and actual usage at the time when cell-site data or communication activity was recorded. (“it’s not my phone” or “I lend it to others” or “many people have access to it”)

 

  • The attribution of a mobile phone is a process in its own right and the subject of much debate beyond the remit of this article. However, similar to the advances of Cell-Site Analysis the ever involving technical and social change continues to produce far more intrinsic user profiling to cement attribution assertions.


 

Developments and effects – The rise and rise of phone ownership and use.

The mobile phone revolution started to gather pace in the late 1990’s as the cost of ownership started to become within the grasp of the mass populous.

 

  • In January 1999 Ofcom estimated that approximately 27% (1 in every 4) of UK adults owned, or had access to, a mobile phone.
  • Just 12 months later that figure had almost doubled and stood at 46% and by November 2001 the figure had risen to 75% (3 in every 4). (OfTel, 2002).

 

Cell-Site Analysis Map
Cell-Site Analysis Map
  • In recent figures, from 2014, the level of UK mobile phone ownership stood at 93% of the adult population (Ofcom).

 

1993    Digital mobile phone networks started to emerge from frontrunners Mercury and Vodafone quickly followed by Orange in 1994. Initial consumer take-up was slow and mostly aimed at the business executive in acknowledgement of the high cost of ownership and usage.

 

Early networks suffered from poor coverage in non-metropolitan areas and internment service quality.  This generated a demand and competition for network companies to dramatically expand their network coverage.

 

 

During the early adoption phones the biggest inhibitor to phone ownership was cost both in terms of handset ownership and monthly running expense from subscription fees and relatively high usage costs.

 

In 1996 Motorola introduced its ‘Startac’ handset the world’s first Clam Shell design with the promise of up-to 8-day battery life.  In the UK the handset retailed at £1,400.

Motorola StarTac Handset
Motorola StarTac Handset

 

1997    In attempt to address the issue of usage costs mobile phone companies introduced ‘pre-pay options to unshackle consumers from the requirement of a monthly contract. The move was to prove a huge success.

 

The subsequent explosion of mobile phone ownership was driven by many social factors but predominantly by the reduction of cost and through advances in handset design and desirability.  Since the turn of the millennium the growth in mobile phone ownership has been exponential.

 

1999    In January 1999 ‘Oftel’ reported that approximately 27% (1 in every 4) of UK adults owned, or had access to, a mobile phone. In the same year (1999) Supermarkets started to sell pre-pay mobile phone bundles with a price point under £100.

 

Unsubscribed pre-pay – ‘burn’ phones

One affliction to the criminal investigation process was, and still remains, the unsubscribed pre-pay option, which adds to the burden of the attribution process.

 

The popularity of pre-pay options and the ease of access to unregistered SIM cards led to the use of short life ‘burn’ phones.  Such phones are frequently acquired by individual’s intent on criminal activity and deployed for very limited periods of time before being discarded and replaced on a regimental basis.

 

2001    In November 2001 UK adult mobile phone ownership had risen to 75% (OfTel 2002) and it had become the norm for a person to own or have access to a mobile phone device.  As a consequence the mobile phone became a more frequent source of potential evidence in criminal investigations.

 

At this time the mobile phone networks deployed 2nd generation (2G) cell-sites. These 2G cell-sites have a theoretical coverage range of 35-kilometres. This value was frequently bandied by barristers as the de-facto argument to throw at cell-site evidence when it got to the courtroom.

 

In reality few, if any, of the deployed 2G cell-sites afforded ranges reaching the quoted theoretical level.  However, at the time, it was not uncommon to find rural based cell-sites with a coverage range in the order of 15 to 20 kilometres and urban based city/town centre cell-sites would often extend in excess of 5 kilometres.  Therefore, the level of affordable accuracy was far from precise and Cell-Site Analysis was frequently referred to as an un-precise science. A further inhibitor to early Cell-Site Analysis was the infrequency of phone usage, which still remained limited due to call and text messaging tariffing.

 

As the consumer boom in mobile phone ownership took hold it drove forward widespread investment and development both for mobile networks and mobile phone devices. At the turn of the millennium mobile phone networks had grown to cover all major cities and towns with 2nd Generation (2G) cell-sites. As the demand for services continued to increase so did the number of mobile phone users at any given location and especially within busy urban environments.

 

The coverage area of a mobile phone cell-site can sustain a finite number of active users/subscribers.  Generally the greater the volume of mobile devices at, or in any, particular location/area then the smaller the size of cell-site required to sustain those devices and combat the signal to noise ratio (SNR) problems.

 

 

 

In 2001 the vogue for mobile phone handsets was for smaller compact designs and few at the time had colour displays. Ericson’s T68 handset was the manufacturer’s first with a colour display.

 

Evolution of Samsung Handsets
Evolution of Samsung Handsets

 

2002    It wasn’t until 2002 that mainstream mobile phone devices started to include a camera option to further enhance their desirability.  This additional option would in part contribute to a greater demand for the transference of digitised data (pictures/video) across the mobile phone network.

 

Coincidently, the development and popularity of the camera option was to play a major part in improving the evidential value of recovering a mobile phone device as the stored imagery (of a subject or their family/associates) would often prove vital in the attribution of a mobile phone device to a particular person.

 

Handset data could also provide vital information with regards to a person’s association with others and in certain cases actual evidence of crimes themselves as criminals took trophy pictures of their actions or ill-gotten gains.

 


 

2003 – Hutchison introduce 3G services   

In 2003, in response to the demand for a greater range of services and higher data transfer speeds, Hutchison introduced the third generation 3G network.  Other network operators would eventually catch-up with the introduction of their own 3G network in tandem with their existing 2G networks.

 

The major impact of the 3G network from a Cell-Site Analysis perspective was that it pulled the rug from under the theoretical 35 kilometre range argument as 3G operated at a higher frequency and had much reduced range potential.

 

Additionally, it created situations where a mobile phone would utilise combinations of 2G and 3G cell-sites, which in-turn improved analysis when examining the service and overlap of the differing technologies at relevant locations of interest.

 

2003 – Blackberry impact upon messaging

In 2003 ‘Blackberry’ came to the market with its RIM 850 device that it marketed as a Personal Digital Assistant or PDA. Significantly, Blackberry were to introduce the Blackberry Messaging (BBM) service that offered instant messaging without the costs then often associated to text messaging.

In the fullness of time, other third-party offerings for instance messaging services came to the fore that could be operated on cross-platform devices.

RIM PDA
RIM PDA

 

To an extent BBM still remains a commonly used communication mechanism uncovered in investigations into Organised Crime Groups.

 

In 2004 Nokia, the then world leading handset manufacturer, released the 7610 handset which was the first to feature a 1 mega-pixel camera.

 

In 2004 Motorola gained huge success with the introduction of the Motorola ‘Razr’ handset with its brushed aluminium casing and 2.2inch TFT screen it became a must have fashion accessory that led to eventual sales of over 130 million devices.  Despite the 0.3megapixel camera and 5MB (yes mega-bytes) of non-expandable memory it would be the top selling phone 2004 – 2006.

Motorola Razr
Motorola Razr Handset

 

In 2006 many network operators were offering of “all you can eat” data plans such had been the growth in demand from consumers now embracing mobile data services.

 

By 2007 Ofcom were reporting 73.5 million active UK mobile subscriptions. (UK Population for 2007 was 61.3 million). Many consumers now ran two or more phones or would use secondary subscriptions for data services.

 

The double-phone use is often found to apply in criminal investigations where a suspect may operate, or be accused of operating, what is often termed ‘Clean Phone’ ‘Dirty Phone’ separating out personal life (clean-phone) and otherwise dubious activity (dirty-phone).

 

In essence though, when such strategies are applied by those engaging in criminal activity the double use of phones merely adds to the level of obtainable evidence. That evidence can subsequently be compared and combined to show a much greater consistency to other events. Additionally, twice the amount of cell-site data may prevail to afford greater scrutiny, particularly in the identification of specifically defined travel patterns.

 

Ofcom reported that by the end of 2007, 17 percent of all mobile users (12.5 million) were using 3G, which had been an 11 percent increase on the previous year.  The uptake in 3G subscriptions would continue to rise.

 

Within the realm of Cell-Site Analysis it was now becoming common place to find a subject’s phone switching between 2G and 3G technologies within the Call Data Records under scrutiny.  This added greatly to the level of analysis that could be applied, as examination could be made into where the two technologies would overlap and where one takes over from another.

 

2007 – Apple gets a bite of the market

In 2007 Apple Inc. branched out into the mobile phone market with the release of the Apple iPhone. Apple already had a loyal customer base from successful sales of IT and multi-media devices and its multi-media management platform ‘i-Tunes’, which was established in 2001.

The introduction of the iPhone was a major development to the ‘Smartphone’ market that intensified brand competition, which continues to drive technological and ascetical development of mobile phones.

 

The capabilities and functions of mobile phones continued to diversify to provide extra added benefit to the consumer in the battle for brand popularity.

Apple iPhone
Apple iPhone

 

A growing number of mobile phones would incorporate GPS technology, which in turn could provide Satellite Navigation functionality. Wi-Fi transceivers were also being incorporated into mobile phone devices to extend the connectivity options for access to the internet and other digital devices.

 

October 2007 saw the commencement of a program to switch over the existing analogue terrestrial TV broadcasting on to a digital broadcast that was to be completed by October 2012.

 

The resulting changeover made particular frequency bands available that were sold under licensed to communication network providers for further expansion and development of the mobile phone network.

 

2008    In 2008 the 4th generation (4G) network was under development in timely anticipation of the ravenous demand for high speed data transfers from media hungry consumers. It would be four years in development before the roll-out of 4G cell-sites that commenced in 2012.

 

The expansion of the mobile phone networks continued to see the installation of more 2G and 3G Cell-Sites (particularly 3G) nationally and generally a continual reduction in the size of cell-site coverage areas across urban and rural environments.

 

  • Governmental policy amended certain planning restrictions in order to facilitate a wide-spread expansion of mobile phone and data networks within the UK.

 

2010    In 2010 the Mobile Network Operator ‘EE’ was formed (then as Everything Everywhere and latter abbreviated to EE) from a merger of network operators T-Mobile and Orange.  Effectively it meshed together the network resources (cell-sites) of each provider.

 

In respect of the Cell-Site Analysis the creation of EE improved the affordable accuracy level when applying analysis in respect of T-Mobile or Orange phones. The merging of networks now allowed analysis to show where and why service ‘crossed-over’ between T-Mobile and Orange resources. Furthermore, the increase of cell-masts now jointly available led to a general reduction in the size of coverage areas of individual cell-sites.

 

The developments of Smartphone capabilities have driven an ever expanding ‘apps’ market covering all manner of entertainment, service, information, and function.

 

2011    In October 2011 Apple announced that their App Store listed over 500,000 application titles for download, that number then exceeded the 1 million mark by October 2013.  The latest figures announced by Apple (Jan 2015) claim that the App Store contained over 1.4 million titles to choose from and that total App Store downloads had exceeded 75 billion.

 

The ‘apps’ themselves often provide a vital source of information in the attribution and/or profiling of a subjects lifestyle and associations.

 

2013 – 2014   Mass Messaging

Deloitte estimated the volume of instant messages composed in Britain doubled from 160 billion in 2013 to 300 billion by the end of 2014. This equates to approximately 820 million instant messages transacted daily (about 12 messages per day sent by every UK resident).


 

Social Media Revolution.

The Smartphone phenomena supports, and is supported by, the social media revolution as it provides the ‘take anywhere – always connected’ portal to access and function. Over the last decade the development of the ‘mobile device’ (Phones, PDA, Tablets, Laptops) has been a perfect marriage to the social media revolution.

 

The rapid adoption of ‘social media’ and the notion of ‘always being connected’ have seen the creation of vast global business empires transacting multi-billion dollar acquisition deals. What makes this more remarkable is that the majority of those business empires predominantly provide a free of charge service to the majority of their subscriber base.  Here we look at a few of the movers and shakers of the social media world.

 

August 2003 Skype              Voice and Video Calling

  • Skype – launched in 2003 and purchased in August 2005 by Ebay for 2.6 billon dollars. It was sold to Microsoft in 2011 for 8.5 billon dollars (Doug Aamoth, Time.com, May 2011)

 

February 2004            Facebook       Social Media Services

  • 3 billon active users by June 2014

 

February 2005            YouTube        Video Sharing Website

  • Conceived in the wake of the 2004 Boxing Day tsunami. In 2015 YouTube’s website claimed more than 1 billion users and estimated 300 hours of video were uploaded every minute and 50% of YouTube views being made from a mobile device.

 

March 2006                Twitter            Social Media Services

  • First ‘Tweet’ posted by the company on 21st March 2006. In 2015 Twitter reported 288 million monthly active users sending over 500 million tweets daily with 80% of users accessing via a mobile device.

 

November 2009         Whatsapp      Instant Messaging App

  • WhatsApp can be used to send messaging, images, video and audio media messages.
  • In October 2014 WhatsApp was considered the most popular messaging app with more than 600 million active users. By January 2015 this had risen to 700 million users.

 

October 2010             Instagram       Mobile Online Multi-Media Sharing

  • Following launch in October 2010 Instagram rapidly gained popularity. The Instagram website of 2015 reported daily uploads of more than 60 million photos by its online community of over 300 million subscribers.

 

September 2011        Snapchat        Mobile online multi-media messaging

  • According to Snapchat in May 2014, the app’s users were sending 700 million photos and videos per day.

 

The development and adoption of both mobile devices and social media highlights the rapid technological and sociological changes that now make a mobile phone the most intrinsic and intrusive evidential hub into everyday life and personal detail.

 

Additionally, the continual rising scale of customer interaction is phenomenal and generates colossal volumes of network traffic.  This continues to drive heavy investment into the underlying network infrastructures that keep mobile phone devices connected.

 

This has again led to a greater level and diversification of technology deployed to maintain and support the connected community.

 

Through development of mobile phones networks there are now 2G, 3G and 4G cell-sites with, differing frequency ranges within these technologies.  The diversification of underlying digital networks from founding 2G technologies is now complemented by increasing numbers of Micro and Pico cell-sites. Development and diversification continue to expand and enhance the level of analysis that can be applied in respect of mobile phone usage and its evidential value.

 

 The main challenge today

One of the on-going challenges facing (mobile phone evidence) Cell-Site Analysis is to educate both Law Enforcement and Litigators that the afforded evidential value has risen exponentially along with the growth and development of the mobile phone networks (technological) and the growth in phone usage (sociological).

 

As the evidential value of Cell-Site Analysis has increased the actual cost of its application has drastically reduced from the overly exhortation prices once charged by entities that monopolised and exploited the Law Enforcement (Prosecution) market.

 

The cost reduction is due to a number of factors including; standardisation of Call Data Records, control on underlying data costs, the development and availability of surveying equipment options, and a wider pool of expertise. These factors, blended with commercial competition have driven down the cost of application.

 

However, as a consequence of the rapid growth the complexity of the mobile phone network, with regard to Cell-Site Analysis, is ever more involved and requires in-depth analysis if it is to be utilised effectively.

 

During the current climate of austerity and budget reductions the prosecution markets are outsourcing less and relying more upon their limited internal resources to provide basic overviews of cell-mast usage. This can have a negative effect both for an actual investigation and ultimately on the criminal justice process, for either prosecution of defence.   It further demines the true value of Cell-Site Analysis and extends the negative viewpoint of an imprecise science.

 

The evidential value of evidence cannot reach full potential if it is not accurately understood.  If the primary decision maker (defendant or juror) is not empowered with the information in an understandable form then the usefulness of the evidence may not be achieved or worse be perceived to establish unsupported facts.

 

When well-presented evidence is produced showing that a properly attributed phone is intrinsically linked to all, or even the majority, of an incident’s milestones and where the overall pattern of consistency can be shown to be robust then such evidence may convince a subject to admit their involvement and guilt. Where this happens, and it often does, the resultant early admission of guilt saves the taxpayer the expenditure of a costly trial process.  Such capital saving cannot be achieved on the back of summary analysis and poorly presented evidence.

 

 

Download – The Evolution of Mobile Phone Evidence.pdf

Encrypted BlackBerry Lock Screen

Private Sector – Digital Forensics Industry First – Encrypted BlackBerry Examinations

Due to ongoing expert Research and Development, SYTECH are proud to announce the “UK Private Sector – Digital Forensics Industry First” regarding the Digital Forensic examination of Encrypted BlackBerry Devices (including PGP encryption).

 

With the rise of Digital Security aware Organised Crime Groups and IT literate persons, this type of complex examination can lead to the convictions otherwise missed due to previously inaccessible data held within these information gold mines.

 

If you have a device with a padlock in the top left of the screen (open or closed) or suspect PGP based encryption then:

Contact us directly to discuss this invaluable service on  01782 286300 or email enquiries@sytech-consultants.com and ask for Simon Lang.

 

We are so confident that we will gladly offer a “no win, no fee” service.

We look forward to hearing from you.

Encrypted BlackBerry Lock Screen
Encrypted BlackBerry Lock Screen

SYTECH Case Study – Digital Forensic Investigations in Cases Against Child Predators and Co-Conspirators

How Cellebrite’s UFED Link Analysis Strengthens Cases Against Child Predators and Co-Conspirators – Mobile Phone Forensic Examinations

 

Who:

Simon Lang, Senior Digital Forensic Consultant / Digital Forensics Manager, SYTECH – Digital FOrensics, Stoke-on-Trent, England

 

What:

Use of Cellebrite UFED Link Analysis to attribute suspect handsets and assess and identify victims

 

Why:

Investigating rings of criminals who produce child exploitation materials

 

Results:

UFED Link Analysis saves time and effort associated with connecting suspects and victims on child exploitation, illegal money lending and drug conspiracy cases

 

Child exploitation can be one of the hardest crimes to prosecute. Victims are often too scared or ashamed to admit any connection to a suspect, and paedophiles go to great lengths to protect one another. To make their cases, police need ways to tie suspects and victims to one another via the frequency, type, and mode of their communications. Often this evidence is found on their mobile phones and GPS devices.

 

Simon Lang, Digital Forensics Manager at SYTECH – Systems Technology Consultants Ltd., England, has put UFED Link Analysis to work on several such cases in recent months. In the United Kingdom, law enforcement agencies frequently outsource digital forensics to ­rms like SYTECH. That’s because when a case goes to trial, the courts require an independent review of the work police did. High pro­le or complex cases with multiple devices often end up in court, so teams like Lang’s need tools that enable them to explain digital evidence simply and concisely at trial.

 

Lang himself has been a mobile device forensics examiner since about 2008, and he and his team have used Cellebrite systems since 2011. However, when faced with multiple mobile devices on a single case, they faced the time-consuming process of running data through spreadsheet software.

 

“Creating custom ­filters in Microsoft® Excel® and looking for common contacts, usernames and IDs, and incriminating content [such as text messages] can take a few hours when comparing the results from iPhones etc.,” says Lang.

 

That’s because of the sheer amount of data that iPhones and other smartphones can store. UFED Link Analysis provides an almost instantaneous graphical representation of the common contacts with the click of a button. “It is easier using these diagrams than looking at rows of text,” says Lang.

 

Why is this important? Lang and his team work on large cases involving multiple defendants across the United Kingdom, including child exploitation and drug conspiracy cases. “This tool comes in extremely handy in child exploitation and grooming cases, which are becoming more common in the UK,” Lang explains. “There are large ‘rings’ of individuals who have been targeting vulnerable people across the country.”

 

One of the most common ways his team uses UFED Link Analysis is for attribution of handsets, when the suspect denies ownership. Investigators can corroborate text messages or instant messaging, call logs, contacts and found on the suspect’s handset with like data found on victims’ or other suspects’ handsets.

 

Lang’s investigators also use UFED Link Analysis to compare “clean” and “dirty” phones. In these scenarios, suspects use one device for everyday noncriminal activities, and a second or more devices for their criminal activities. Common contacts and locations between the two can show which devices are used by the same suspect(s) and thus, can tie otherwise “innocent” suspects to the crimes they commissioned or committed.

 

The software is also handy for assessing multiple victims on these cases. The “Links-Mutual” view shows whether victims all had one or more suspects in common on their devices; patterns in keywords or timelines—days of the week or times of day—can help corroborate the evidence.

 

Once the evidence is collected and analysed, Lang uses the snapshot option to show common contacts within cases, placing these within his report. Put together, the links and patterns strengthen the Crown’s case and lead to what Lang believes will be a higher likelihood of conviction.

 

About Cellebrite Founded in 1999, Cellebrite is known for its technological breakthroughs in mobile forensics. Its Universal Forensic Extraction Device (UFED) is used internationally by law enforcement, military, intelligence, corporate security, and eDiscovery agencies to extract data from legacy and feature phones, smartphones, portable GPS, tablets and phones manufactured with Chinese chipsets.

 

SYTECH – UFED Link Analysis – Child Exploitation Case Study

Forensic analysis of a Sony PlayStation 4: A first look – Presentation Slides – Matt Davies – SYTECH

To accompany the fantastic research carried out by Matt Davies (SYTECH) et al. from:

http://sytech-consultants.com/forensic-analysis-of-a-sony-playstation-4-a-first-look-matthew-davies-digital-forensic-analyst-sytech/

The presentation slides from the DFRWS (Digital Forensics Research Conference) Europe 2015 Annual Conference are now available below:

Forensic analysis of a Sony PlayStation 4 – Matt Davies – SYTECH

Forensic Focus Interview – Matt Davies – Digital Forensics Analyst – SYTECH

Matt, you’re a digital forensics analyst at SYTECH. Tell us a bit about your role and what it involves.

My role at SYTECH predominantly involves the extraction and analysis of embedded devices, such as mobile phones, tablets, satellite navigation systems, games consoles, unknown devices etc. The examinations I am involved in vary considerably and range from indecent images of children (IIOC) to providing assistance in murder investigations. Working for a private organisation, such as SYTECH, allows me to experience both prosecution and defence based cases.

What first made you interested in digital forensics as a field?

It was the varied nature of the work accompanied by the opportunity to make a difference that attracted me to the field of Digital Forensics.

I really didn’t want a mundane or repetitive job; I wanted a career that would provide both challenges and stimulation, so far I have not been disappointed! I have a real passion for forensics and love what I do.

At DFRWS you presented some research on forensic analysis of a Sony PS4. Could you briefly outline this for our readers?

The Sony PlayStation 4 is the most powerful 8th generation games console on the market. As of March 2015, there are over 20,000,000 devices in worldwide circulation. The console’s security features, such as encryption, face recognition technology and passcode protection, make this device the perfect weapon for criminals. Therefore it was essential that an analysis method be devised for this device. The proposed best practice methodology is the result of over 50 experiments conducted upon the PlayStation 4 over a 12 month period.

In the first instance the console’s hard drive is removed, imaged and restored upon a duplicate HDD using a Linux based system. A shadow drive is then inserted between the console and the duplicate drive, which receives all write requests and as such prevents the alteration of data stored upon the HDD. The operational effectiveness of the shadow drive was evaluated in the following manner: The duplicate HDD was imaged and verified. An online analysis of the console’s Internet web browser was conducted and the HDD removed and verified. A comparison of both the MD5 & SHA-1 hash values concluded that no alterations were made to the HDD during the analysis.

A technique that can be exploited by the user enables images viewed online to be stored upon the device. These images are stored as screen captures and can easily be copied to a USB pen drive for evidential purposes. Image and video content acquired via the console and saved to an alternative device (under a different file name) contain metadata that includes the device make & model, firmware version used, original file name and the date and time created. This information can be correlated to the suspected device responsible for creating the artefacts.

One of the greatest challenges with the PlayStation 4 is the continuous updating of system firmware. It has been observed that firmware updates take place at around 8 week intervals and provide additional features as well as “system stability” updates (suspected updating of encryption keys). For each firmware update where the experiments were repeated, the results differ considerably between firmware versions.

You mentioned that one investigative challenge is that Sony is now storing the majority of PlayStation data on the PlayStation Network rather than on each device. Talk us through the unique challenges associated with this, and how they might be addressed.

Having previously evaluated the operational effectiveness of the shadow drive when viewing non PlayStation Network (PSN) dependent content, a second experiment focusing upon PSN was conducted. The experiment involved connecting the console to PSN and sending a single message to a friend, whilst utilising the shadow drive. The console was then rebooted and the message content analysed. The first iteration demonstrated that the message was not visible upon rebooting the console. For validity reasons, the experiment was repeated. On this occasion both the initial and second messages were visible. The experiment was repeated a final time and it was apparent that all messages sent whilst connected via a shadow drive were visible. Therefore, the shadow drive does not prevent data stored in PSN being altered. This presents a significant challenge as data stored in the PSN is duplicated, in part, upon the console’s HDD, meaning that an investigator accessing PSN content without a shadow drive could potentially overwrite existing data or unintentionally delete vital evidence.

The best solution is to use a secondary console to view PSN content. Creating a basic user account without any data will result in that account being populated with the user’s content upon logging into PSN, including unique PSN gamer ID, profile information, messages, party, friends, What’s New, Notifications etc. In addition, an investigator can also access partial PSN data by logging into the suspect’s account via a PC browser. The Sony Entertainment Network (SEN) can be used to prove ownership and contains the user’s real name, address, credit card details etc.

Additional challenges are presented by the console’s remote access features: such options should be disabled, the console restarted and the changes verified prior to conducting an online analysis of the device. In addition, investigators should disable the PSN automatic login feature in order to prevent the alteration of PSN content.

How do you think the world of digital forensics will change over the next few years?

Security Features
The industry trends seem to indicate a significant increase in the use of security features such as encryption, biometrics and passcode protection. Over the coming years such features are likely to become more widely utilised, and as a result present greater challenges to forensic investigators.

Technological Evolution
It has been said for many years that the line between personal computers and embedded systems is becoming increasingly blurred. The technological advancements, accompanied by larger storage capacities, will continue to present significant problems for digital investigators. According to Sony, the PlayStation 4 possesses 43 times the processing power of the PlayStation 2 and 10 times that of the PlayStation 3. One can’t help but wonder what the PlayStation 5 will have in store for us!

Social Media
The sharing capabilities of the PlayStation 4 enable social media websites such as Facebook, Twitter and Youtube to be synced with the device. Tablets and mobile phones also encourage users to share content via social media applications, the whole area seems to be expanding at an alarming rate.

We only need look at the development in mobile phone forensics over the past 5 years to see how far the field of digital forensics has already come. The challenges faced by investigators in the coming years will greatly surpass those seen in previous years, providing a solution to these is far from impossible. Perhaps the greatest change to the field of digital forensics will be the operational requirement for dedicated Research & Development teams within every organisation. We might also see a significant shift from traditional forensic techniques and the reliance upon industry standard tools. There has been a great deal of debate in this area and as to whether or not the whole forensics process is becoming automated. I think it’s an interesting discussion and one that is likely to continue in the future.

I am currently continuing further research into game console forensics and intend on presenting the results at DFRWS 2016, Switzerland.

Matt Davies is a Digital Forensics Analyst at Sytech, who work on digital investigations across all areas including criminal justice, civil litigation and corporate.

Forensic Focus interviewed Matt at DFRWS, the annual Digital Forensics Research Workshop, which took place in Dublin from the 23rd-26th of March. The next workshops will be held in Philadelphia in August 2015, and Switzerland in March 2016. You can find out more and register here.

Original Forensic Focus Article

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