Cracking Passwords in Forensic Investigations - Scholarly ...

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iv I would also like to thank my fellow Master of Forensic I.T. classmates. I have learnt a great deal just from discussing all study matters with them. I have also gained a lot of moral support and encouragement from their company and friendship. I would also like to thank my editor Marjorie Carlson. She helped me a great deal by editing and proofreading this thesis in order to make it reader friendly. I would like to thank all of my family members. Without their love and kind support, I would not have been able to perform research. I would like to thank my mother, Mrs Pooja Bulland, and my father, Mr Ved Bulland, for the values that I learnt from them, which made me who I am in my life today. I would like to thank my younger brother, Dhiren Bulland, for his love, kind support, and company during my research study here in Auckland. My family means the world to me, and the research that I have performed is all a result of their endless love and kind support. Finally, a big thank you to everyone responsible in any way, to those whose names were mentioned here and also to those whose names I accidentally forgot to mention and give due credit to.
v Abstract Digital Forensic Investigators need to forensically analyse digital data in order to investigate various crime cases. Quite often, the investigators come across password protection for the digital data that they need to investigate. Therefore, they need to crack passwords in order to gain access to potential evidence. There exist various problems in the field of password cracking. Due to technological advances in security, it currently takes—and is expected to continue taking—large amounts of time for digital forensic investigators to crack passwords. Due to the large amount of time required to crack passwords, the costs involved in cracking the passwords are also high. There also exists an ambiguity with regards to the outcome of the password-cracking procedure. Thus, there is a risk of the forensic investigator not being able to find the correct password even after spending large amounts of time and money. Apart from the ambiguity of the outcome and large password-cracking times, there also exists uncertainty regarding the amount of time a password may take to crack. While a variety of research in the field of password cracking exists, past studies have mostly concentrated on the underlying password-cracking technology in use. They have not examined the underlying procedures and practices involved in cracking passwords. In order to address the various challenges mentioned above, this research proposes the use of a budgeting model. The budgeting model aims to gain control over the amount of time required to crack a password. This also makes it possible to gain control over password- cracking costs. This research also defines an experimental design to define and test the processes involved using the budgeting model. This research consists of a simulation of 200 hypothetical password-cracking cases, classified in groups or blocks of 50 password cases. The various time budgets for each block of passwords are calculated before the actual password-cracking experiment is performed. The password-cracking experiment is then performed as per the defined processes for a period of seven days. The experiment is also monitored regularly. The actual password-cracking times for all of the passwords are also recorded. The data are then analysed. There are certain variations involved in the processes and results, which have been considered during analysis. The results find that the actual password-cracking times were less than the times allocated by the use of the budgeting model. Therefore, the budgeting model guidelines are demonstrated suitable to be followed as best-practice advice for digital forensic investigators. The results also show that the actual times required to crack the passwords are very near to half of the expected budgeted time.
Page 1 and 2: Cracking Passwords in Forensic Inve
Page 3: iii Acknowledgements This thesis wa
Page 7 and 8: vii Table of Contents Declaration .
Page 9 and 10: ix Chapter 4 - Research Findings 4.
Page 11 and 12: xi List of Tables Table 2.1: The Mo
Page 13 and 14: xiii List of Abbreviations AMD Adva
Page 15 and 16: 1.1 PROBLEMS FOR DIGITAL FORENSIC I
Page 17 and 18: approach improves the password crac
Page 19 and 20: technologies, there exist challenge
Page 21 and 22: 2.1 PASSWORDS AND PASSWORD RECOVERY
Page 23 and 24: 2.1.2 Unix/Linux MD5 Password Schem
Page 25 and 26: encrypting the information within s
Page 27 and 28: iii) If possible, create a custom d
Page 29 and 30: Since all possible permutations and
Page 31 and 32: L0phtCrack 6 supports the retrieval
Page 33 and 34: i) Decryption attack: As discussed
Page 35 and 36: Full cost refers to the total amoun
Page 37 and 38: As shown in Table 2.3, a password w
Page 39 and 40: 5) Weir, Aggarwal, Medeiros, and Gl
Page 41 and 42: the speed of cracking and the attac
Page 43 and 44: is inevitable) but rather the optim
Page 45 and 46: Klein (1990) addressed the most com
Page 47 and 48: character hashing. Thus, for passwo
Page 49 and 50: experiments were conducted by gener
Page 51 and 52: obtained via phishing attacks on th
Page 53 and 54: Bengtsson (2007) outlined a literat
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applications whose passwords need t
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equired for computing and testing.
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3.2.3 The Research Questions and Hy
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main experiment, which is the next
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12,500 x 8 = 100,000 passwords/seco
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3.3.5 Data Map Figure 3.2: Research
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4.0 INTRODUCTION Chapter 4 Research
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4.1.2 Time Budgeting The time budge
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Another computer with the same conf
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minutes, and 24.8 days respectively
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vishal@vishal-desktop:~$ sudo addus
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Table 4.4: Monitoring/action-perfor
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4.3 ANALYSIS OF DATA The experiment
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Table 4.6: First 10 accounts’ pas
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DD:HH:MM:SS format, similar to the
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4.4 PRESENTATION OF DATA FINDING Af
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Figure 4.8 shows the time taken for
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Figure 4.11 displays the comparison
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5.0 INTRODUCTION Chapter 5 Research
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Thus, the simulation mirrored the f
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Table 5.1: Testing hypothesis H0 Hy
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Table 5.3: Testing hypothesis H2 Hy
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Q3: What are the guidelines for bes
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Since the passwords were arranged i
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Analysis (see Section 3.2.3). All f
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information for forensic investigat
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5.3.1.2 Second Step - Find Password
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Therefore, T (in seconds) = 12,500,
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6.0 RESEARCH SUMMARY Chapter 6 Conc
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udgets, the passwords were added to
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SECONDARY RESEARCH QUESTION 3: What
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overcome the security barriers of p
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Clayton, R., & Bond, M. (2003). Exp
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Openwall Project. (2010). John the
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APPENDIX 1: Time Budget Calculation
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51 Bas -2-38 TOTAL TIME REQUIRED FO
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96 Bas -2-27 97 Bas -2-28 98 Bas -2
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140 Adv -1-26 141 Bas -3-07 142 Adv
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182 Adv -1-21 183 Adv -1-22 Diction
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main12:$1$CSD0Tppt$0gO4c883evmn9sQR
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main41.txt: main41:$1$B43.jKTn$5EPi
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main70.txt: main70:$1$7kHK0PnH$yJ5x
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main99:$1$UQiTB..u$SJUkwarkM1kzvnvt
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main128.txt: main128:$1$n7OEbAyB$d6
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main157.txt: main157:$1$VRmaYxPu$Iy
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main186:$1$HFNaeUkb$t1lZ5QcrH9iy8G/
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SHA 1: a168282ad70a94fbb8d5917f3505
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C:\Main Test\MainTest-passwdFiles\B
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Job Started: 7/13/10 8:49:24 File M
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File Modified: 7/13/10 6:58:08 SHA
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File Version: Unknown Job Started:
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SHA 1: b95b12e95c70b66df01af148502e
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File Size: 60 File Version: Unknown
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Job Status: Finished on 7/13/10 8:5
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Identified Type: *nix passwd File S
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Password Type: Password Where Found
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Job Status: Finished on 7/13/10 10:
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MD5: df7c66c8b6b8528176d42314926021
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Result: trapezoidal@ Description: U
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Where Found: (ADV-1-20) Dictionary
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Password Type: Password Where Found
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Where Found: (BAS-3-04) Dictionary
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Commonly Registered Type: crypt use
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Where Found: --- C:\Main Test\MainT
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MD5: 17632fca93fa27bb8d0a89c80a2ba9
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Description: Unknown Password Type:
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File Version: Unknown Job Started:
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APPENDIX 4: Time Analysis for all B
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main60 main61 main62 main63 main64
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main127 main128 main129 main130 mai
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main192 main193 main194 main195 mai
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