Curator,+CISSE v01 I01 A03
Curator,+CISSE v01 I01 A03
 Abstract – Computer forensics is a continually evolving field, filled with challenges when existing
 hardware and software technologies progress and new devices and technologies are added to the mix.
 It is important for forensics investigators responsible for acquiring, preserving and analyzing digital
 evidence, to be aware of the challenges facing the forensics field and to apply latest technologies in
 forensics investigation.
 This paper discusses the challenges to the traditional forensics procedures and technologies due to
 evolving hardware and software. The authors present the latest forensics technologies and procedures
 as well as research ideas to address the challenges, especially in mobile device forensics, Solid State
 Drive (SSD) evidence recovery and analysis, and Windows memory forensics. Corresponding labs are
 designed and presented to assist computer forensic students and practitioners in getting acquainted
 with and practicing the new knowledge and tools.
 Index terms – Windows Memory Forensics, Mobile Device Forensics, Solid State Drive, Forensics Lab
 Design, Forensics challenges
I. INTRODUCTION
 With the proliferation of computer and networking technologies, computer crimes such as child
 pornography, cyber terrorism, espionage, network intrusion, fraud, and theft of intellectual property have
 been steadily increasing in recent years. Digital forensics, since its inception in 1998, has been evolving
 fast and gradually maturing in forensics standards, processes and technologies. Digital forensics
 technologies such as EnCase [1], Forensics Toolkit (FTK) [2] and ProDiscover Forensics [3] were
 developed, thus allowing analysts to acquire, preserve, and analyze digital evidence locally and remotely.
 These technologies are widely used in both civil and criminal investigation by forensics examiners and
 analysts within law enforcement, military, government, and private corporations, seeking to uncover
 evidence of illegal activity. However, evolving hardware and software technologies such as mobile
 devices, solid-state drives, cloud computing, memory-only malware, etc. present new challenges to the
 traditional forensics procedure and technologies of finding digital evidence of a crime [4].
 Memory forensics: Traditionally, computer forensics has focused on evidences that reside in hard drives
 after a suspected crime has been committed. Over the past few years, due to the migration of malware into
 memory, and the increasing use of encryption by adversaries, forensics investigators realized that it is no
 longer sufficient to pull the plug and take the suspect machine back to the lab for gathering nonvolatile
 digital evidence [5, 6, 7]. Instead, they also have to include analyzing the computer RAM for examining
 passwords, running processes, memory and network connections, since this process may be the only way
 to start an investigation.
 Mobile devices: Mobile device forensics has expanded significantly over the last decade due to the
 increasing storage capacity and processing power of these devices, a wide range of advanced applications,
 various wireless connectivity options, and their portability. Besides storing, processing, and
 communicating both personal and corporate information, mobile devices have also been widely used in
 online transactions such as stock trading, flight reservations and check-in, and mobile banking, to name a
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                                 Proceedings of the 17th Colloquium for Information Systems Security Education
                                                                            Mobile, Alabama June 10 - 12, 2013
few [8]. The great potential for incriminating data to be stored on mobile devices has created a need for
mobile device forensics to allow forensics investigators to capture evidence in a criminal investigation.
Mobile device forensics is the process of recovering digital evidence from a mobile device under
forensically sound conditions and utilizing acceptable methods. It is important for forensics investigators
to develop an understanding of the working components of a mobile device and the appropriate tasks to
perform when they deal with them for a forensic assessment [8].
Solid-State Drives: When presenting admissible evidence to the court, forensics investigators have to
ensure its integrity and authenticity. Integrity is ensuring that the act of seizing and acquiring digital
media does not modify the evidence (either the original or the copy). Authenticity refers to the ability to
confirm the integrity of information. Storage media technology was based on magnetic devices over
the past two decades, allowing digital forensics to play a vital role in legal prosecution by
providing invaluable and authentic allocated and unallocated data as admissible evidence. This
landscape is changing when flash-based solid-state drives are rapidly becoming a popular replacement
option for traditional magnetic hard drives. Due to the SSD technologies such as wear-leveling and
automatic garbage collection, recovering deleted and unallocated data as well as providing authentic data
becomes challenging, even impossible in some cases [9, 10, 11]. This is the first call to challenge
traditional forensic practices and procedure [10].
XXXX University is one of the leading institutions that offer courses specifically developed for the digital
forensics curriculum and information security degree program. Since our first forensics course was
developed in 2003 [12, 13], the digital forensics field has been evolving continuously. The forensics
experts in academia, industry and government continue to develop innovative tools to overcome the
challenges in this field. The faculty at RIT have been diligently updating the forensics labs to prepare our
students with latest forensics technologies, in order to face the new challenges in the digital forensics
filed. In this paper, the authors share their latest lab development in memory forensics, mobile device
forensics, and SSD data recovery and analysis, with educators and researchers.
The remainder of this paper is organized as follows. Section II describes three emerging forensics areas
along with the background knowledge and challenges for each area. The detailed design and activities for
the three correspondent labs are presented in Section III. Section IV briefly covers the authors’
experiences in using these labs, followed by Conclusion and References in sections V and VI
respectively.
Digital forensics is a relatively young, but a rapidly evolving field. The years from 1999 to 2007 were
considered to be the “Golden Age” for digital forensics, since techniques and processes allowing
forensics investigators to recover deleted data from unallocated spaces, email, instant messages and web
browsers, and retrieval of deliberately hidden data from storage were developed. However, since 2008,
hardware and software changes such as drive encryption, memory-only malware, solid-state drives,
mobile devices, and cloud computing, present new challenges to the traditional forensics procedures and
analysis. In this section, the authors focus on explaining the three emerging forensics areas: Windows
memory analysis, solid-state drive analysis and mobile device analysis.
   A. Windows Memory Acquisition and Analysis
Since 2008, the use of drive encryption, data in the cloud, and memory-based malware has increased.
Many of digital forensics evidences are only stored in memory, and therefore are not possible to be
captured using disk forensics analysis alone. On the other hand, Random Access Memory (RAM) stores
volatile information such as running process/threads, network connections, open files and open registry
keys for processes, user names and passwords, unpacked/decrypted versions of a program, including
memory resident malware [6]. RAM forensics can capture the current state of a machine. As a result,
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                                 Proceedings of the 17th Colloquium for Information Systems Security Education
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there has been substantial interest in RAM-based forensics in an effort to help address many of the
challenges facing the digital forensics community, including defeating drive encryption and identifying
malware that is not written to persistent storage. In 2008, the first Open Memory Forensics Workshop
(OMFM), focusing on open source volatile memory analysis [14], was organized to bring together digital
investigation researchers and practitioners to discuss the latest advancements in volatile memory analysis.
As the authors stated in [15], “Live Digital Forensics is a critical capability for digital forensics
practitioners today and will only become more critical as time marches on.”
   B. Mobile Device Forensics
The use of mobile phones in crime has been increasing recent years, but the forensic study of mobile
devices is a relatively new field. The proliferation of mobile devices in the consumer market demands a
new framework and forensic tools to acquire and analyze information such as e-mail, word processing
files, spreadsheets and personal information, including user’s Global Positioning System (GPS) tracking
information, call history, SMS, MMS and social networking messages, photos, web surfing information
etc. [8]
The process of recovering and analyzing digital evidence from a mobile device must follow forensically
sound conditions and must utilize acceptable methods. In other words, the evidence has to be handled in a
tamper-proof manner and by a justifiable technology or methodology, avoiding unnecessary and
undocumented evidence changes, so that the evidence will be admissible according to law in a trial. Even
though many mobile forensics tools are being developed for logical and physical mobile device evidence
acquisition and analysis, law enforcement and forensics investigators have struggled to effectively
manage digital evidence obtained from mobile devices [8].
Some of the challenges faced by a forensics investigator in obtaining information from mobile devices
include the following:
1. Data representing evidence on mobile devices can be volatile, because these devices are constantly
exchanging information via Wi-Fi, 3G/4G cellular or Bluetooth connections. Therefore new data may be
overwritten over original evidence. The most important step for a first responder is to determine the best
way to preserve the mobile device and its data, when arriving at the scene of crime. The common process
is as follows:
    a) Power the mobile device off to preserve data and battery power. In this case, there is a chance of
       losing critical evidence resided in the flash memory, such as open processes, applications, and
       deleted information.
    b) Place the device in Airplane Mode, if the device supports this function, to suspend the device’s
        signal transmitting functions, therefore preserving data.
    c) Isolate devices from cellular, Wi-Fi, Bluetooth and other radio signals using appropriate measures
        such as Black Hole Faraday bags [16] or Ramsey RF Shield Test Enclosure [17] to prevent a
        potential remote wipe or alternative techniques directed to alter or destroy evidence in the device.
2. File systems that are present in mobile devices operate from volatile memory that requires power to
maintain stored information.
3. A large variety of operating systems are embedded in mobile devices, thus making a standardized
forensic process development challenging.
4. The short product cycles from the manufacturers to provide new mobile devices and their respective
operating systems are making it difficult for law enforcement agencies to remain current with new
technologies.
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                                                                              Mobile, Alabama June 10 - 12, 2013
Labs provide students with the opportunity to understand and demonstrate the above-mentioned forensics
challenges. They also allow students to discover new ideas for their future research. Various labs are
designed in an effort to address the forensics challenges presented in section II and to allow students to
practice related activities in a safe and controlled environment. The listed technologies are selectively
included in each lab. The rationale behind choosing “good” tools is to either choose court accepted
commercial tools or community open source tools that are endorsed by SANS, NIST, etc. Also, each lab
leaves some open-ended questions that allow students to conduct further research, which may evolve into
their graduate thesis/project topic.
Consequently, we introduce three labs - each directly addressing the challenges presented in section II.
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                                 Proceedings of the 17th Colloquium for Information Systems Security Education
                                                                            Mobile, Alabama June 10 - 12, 2013
2. Lab Activities:
Step 1. Memory acquisition using Cold Boot Attack
Since the compromised machine is encrypted, students will have to first recover the password to decrypt
the drive. In this lab, students will explore the “cold boot attack” method.
The cold boot attack, introduced by the Princeton research team [21], is a technique for acquiring the
contents of a computer and finding cryptographic keys in memory images after rebooting a machine [22].
In the paper [21], the researchers confirmed that simply turning off a computer does not necessarily
ensure that all its memory contents are lost. Secondly, they have shown that the rate of decay for
computer memory is dependent on two key variables, time and temperature, which means that one can
pull power off the machine first, and then immediately reboot it and grab the contents of the RAM.
The cold boot attack includes several tools [22].
    • Scraper.bin – A bootable image to dump the memory to a usb
    • Usbdump – Dump the RAM from the USB to your forensics system
    • Aeskeyfind and rsakeyfind – searches for AES keys ad RSA keys
Students will boot the compromised machine from a USB that contains Scraper.bin. The memory will be
automatically dumped to the USB. Then, students will dump the memory content to a forensics machine
using Usbdump and run Aeskeyfind or rsakeyfind to attempt to recover the encryption key, in our case, the
TrueCrypt key.
The cold boot attack obviously is a powerful tool in the computer forensic investigator's bag of tools.
However, this method relies on many variables in order to make it actually work. Also, the digital
forensics community is still debating whether cold boot attack produces a sound forensics memory
acquisition. Therefore, this method is only used in extreme circumstances where it may be the only viable
option available and may make all the difference between succeeding in finding evidence and leaving
empty handed [23].
Students have to justify the circumstances in which they will use the cold boot attack method.
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                                  Proceedings of the 17th Colloquium for Information Systems Security Education
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In this exercise, students will use Volatilty Framework, Mandiant’s Memoryze and Mandiat Audit Viewer
to discover the hidden “nc” network connection. Note that discovering the migrated malware is a
challenging activity. Once the malicious processes are identified, students will dump them out (using
Volatility’s procdump, or other tools), finally, use a disassembler such as debugger IDA Pro [29] or
ollydbg [30] to analyze the executable.
At this point, students are comfortable with the Windows memory acquisition and analysis tools. Now the
question is whether there are technologies that can defeat Windows memory forensics. In December of
2012, researchers created an anti-forensics tool called Dementia [31] that exploits memory acquisition
tools and prevent these tools from finding hidden objects and processes. Students will validate whether
they still can find hidden processes using Volatility Framework after running Dementia.
Lab Activities:
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Step 1. Seizure
Mobiles devices are often seized live. As the aim of seizure is to preserve mobile evidence when
transporting the device to a safe location for acquisition, the first responders may use a seizure method
listed below.
    a. Turn off the iPhone
    b. Place the iPhone in Airplane Mode to suspend the device’s signal transmitting functions therefore
       preserving data.
    c. Isolate the iPhone from cellular, Wi-Fi, Bluetooth and other radio signals using appropriate
       techniques such as Black Hole Faraday or Ramsey RF Shield Test Enclosure, to prevent data
       exchange/changes.
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                                 Proceedings of the 17th Colloquium for Information Systems Security Education
                                                                            Mobile, Alabama June 10 - 12, 2013
Students are required to document the seizure actions. After trying different types of seizure and
acquisition methods, students will document the analysis results including pertinent evidence. Based on
the analysis result, student will justify whether some actions will potentially modify the original evidence
or fail to capture pertinent evidence. They should conclude: If the device is found switched on, DO NOT
switch it off and if the device is found switched off, DO NOT switch it on.
Lab Activities:
Step 1. Observing evidence changes caused by Wear-Leveling and Garbage Collection
Both Wear-Leveling and Garbage Collection algorithms may result in data being moved around or
removed from physical flash memory locations without any external input by users. Since these
operations are managed by the onboard SSD controller, deletions may occur independently of any
commands issued by a host device controller of the motherboard or the operating system.
Student will explore and verify that SSDs can present different evidence compared to HDDs, when
actions such as creation and deletion of data have occurred for both in precisely the same manner. Various
forensics tools such as EnCase and FTK can be used to analysis the deleted sectors to determine whether
the sectors are cleaned/overwritten/intact.
A variety of test scenarios will be designed by students to track the results of minor changes in the
contents of a drive. These tests could include the modification of an individual file, the deletion of an
individual file using various operating systems, the partial overwriting of a file, and the formatting of the
drive with both quick and full formatting.
Step 2. Determining whether a write-blocker will prevent evidence changes on an SSD
Hardware or software write-blockers are commonly used in forensics acquisition as standard mechanisms
to prevent modification of drive contents by blocking write commands. Unfortunately, the presence of a
write-blocker to a SSD does not prevent irrecoverable data loss from occurring. Students will explore and
demonstrate that even a physical hardware write- blocker fails to prevent automated evidence changes on
an SSD.
Step 3. Determining the events that trigger evidence change and loss
After observing the changes caused by wear-leveling and Garbage Collection, students will further
research and determine which events are more likely to trigger evidence loss. For example, students will
study the SSD-specific command TRIM to understand its behavior. The TRIM command is designed to
enable the operating system to notify the SSD of the pages of data that are marked to be erased by the
user or operating system itself. During a delete operation, the OS will not only mark the sectors as free for
new data, but it will also send a TRIM command to the SSD with the associated Logical Block
Addressing (LBAs) to be marked as no longer valid. After that point, the SSD knows that those marked
LBAs can be cleaned during Garbage Collection.
Step 4. Developing methodology to rebuild evidence for forensics investigation (Bonus Point)
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                                 Proceedings of the 17th Colloquium for Information Systems Security Education
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To address these challenges, students will research for technologies that may rebuild evidence utilizing
logged information from a journaling OS and existing software tools after data change has occurred. As
this is an open-ended question, many students choose to work on it as an independent study or a thesis
topic (for graduate students).
Both the Windows Memory acquisition and analysis (without Dementia and Metasploit) and the mobile
forensics labs were offered twice for forensics students. The labs truly inspired students’ curiosity and
interests in forensics research and developed their critical thinking capability. The SDD lab was newly
designed and was first offered as a graduate-level group research project. Students are especially
interested in discovering the hidden SDD controller activities to impact the traditional forensics process
and procedure. Many students expended the project and labs activities and worked on these challenging
areas as independent studies and even M.S. thesis.
V. CONCLUSION
Digital forensics is an ever-evolving field filled with challenges and opportunities. As the technologies,
software and hardware are advancing, students have to be aware of the challenges and acquaint the latest
technologies to stay on top of forensics field. This paper presents the design and authors’ experience in
developing three research-oriented forensics labs – Windows memory acquisition and analysis, Mobile
forensics analysis and Solid State Drive analysis. These labs introduce the challenges facing the forensics
investigators as well as the cutting edge technologies to address the challenges in the digital forensics
field. We believe that these forensics labs will help other forensics educators to update their forensics lab
activities and encourage them to introduce similar research oriented labs and activities in their forensics
courses.
VI. REFERENCES
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[12] Troell, L., Pan, Y., and Stackpole, B., “Forensic Course Development,” Proc. of Conference on
Information Technology Curriculum 4. North Carolina, 2003.
[13] Troell, L., Pan, Y., and Stackpole, B., “Forensic Course Development – One Year Later,” Proc. of
the SIGITE 2004 conference, Salt Lake CIty, Utah, 2004.
[14] Open Memory Forensics Workshop (OMFW), https://www.volatilesystems.com/default/omfw,
2008.
[15] M. J. Decker, W. G. Kruse, B. Long, and G. Kelley, Dispelling Common Myths of Live Digital
Forensics, www.dfcb.org/docs/LiveDigitalForensics-MythVersusReality.pdf
[16] Black Hole Faraday bags, http://edecdf.com/products?iProdId=1
[17] Ramsey RF Shield Test Enclosure, http://www.ramayes.com/rf_shielded_forensics_enclosure.htm
[18] David Kennedy, Jim O’Gorman, Devon Kearns, and Mati Aharoni. Metasploit - The Penetration
Tester’s Guide. No Starch Press, San Francisco, 2011
[19] FUTo Rootkit: http://www.rootkit.com/board_project_fused.php?did=proj31
[20] Truecrypt: http://www.truecrypt.org/
[21] Halderman, J. Alex, Schoen, Seth D., Heninger, Nadia, et al. Lest We Remember: Cold Boot Attacks
on        Encryption      Keys,       Proc.     of      2008      USENIX       Security      Symposium,
http://citp.princeton.edu/pub/coldboot.pdf, Princeton University 2008.
[22] Cold Boot Attacks code, https://citp.princeton.edu/research/memory/code, 2008
[23] R. Carbone, C. Bean, and M. Salois, An in-depth analysis of the cold boot attack: Can it be used for
sound forensic memory acquisition? Defense R&D Canada, TM 2010-296, 2011
[24] N. Davis, Live Memory Acquisition for Windows Operating System, Eastern Michigan University,
www.cert.org/archive/pdf/08tn017.pdf, 2008.
[25] MoonSols Windows Memory Toolkit, http://moonsols.com/product
[26]                                        ManTech’s                                       MemoryDD,
http://www.thefreelibrary.com/ManTech+Memory+DD+Version+1.3+for+Forensic+Analysis+of+Comp
uter...-a0182984027
[27] The Volatility Framework https://www.volatilesystems.com/default/volatility
[28] Memoryze, http://www.mandiant.com/products/free_software/memoryze/
[29] Mandiant Audit Viewer, http://www.mandiant.com/products/free_software/mandiant_audit_viewer/
[29] IDA Pro https://www.hex-rays.com/products/ida/index.shtml
[30] ollydbg, http://www.ollydbg.de/
[31] dementia, http://events.ccc.de/congress/2012/Fahrplan/events/5301.en.html
[32] Paraben SIM Card Seizure, http://www.forensicswiki.org/wiki/Paraben_SIM_Card_Seizure
[33] SIMiFOR, http://www.forensicswiki.org/wiki/SIMiFOR,
[34] SIM Explorer, http://www.forensicswiki.org/wiki/SIM_Explorer
[35] BOBILedit!, http://www.mobiledit.com/
[36] SimCon, http://www.forensicswiki.org/wiki/SIMCon
[37] Physical acquisition tools iXAM, http://ixam-forensics.com,
[38] Zdziarski technique, http://www.iosresearch.org/
[39] Cellebrite’s UFED, http://www.cellebrite.com/forensic-products/ufed-support-center/tutorials.html
[40] Lantern, http://katanaforensics.com/
[41] Oxygen, http://www.oxygen-forensic.com/en/download/
[42] AccessData Mobile Phone Examiner Plus (MPE+), http://accessdata.com/products/computer-
forensics/mobile-phone-examiner
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