Cracking Passwords in Forensic Investigations - Scholarly ...

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v) Customise rules and dictionaries: PRTK and DNA allow users to create or import custom dictionaries. It is also possible to create biographical dictionaries that allow you to enter the suspect‘s biographical information to aid in password recovery. PRTK and DNA also maintain a golden dictionary that contains previously recovered passwords. They also support creation and customisation of password recovery rules, or modifications that can be made to dictionary keywords to be used for guessing passwords. For example, it is possible to add any prefixes or postfixes and to choose any variations in character sets to customise password recovery. vi) Use add-ons: PRTK and DNA support various add-on products. These add-ons include rainbow tables and Portable Office Rainbow Tables released by AccessData Corp. PRTK and DNA also support Tableau TACC1441 Hardware accelerator (TACC). The use of TACC reduces dictionary-based password recovery times. Thus, it is possible to increase speed and accuracy with the use of various add-ons. 2.4 COSTING PASSWORD CRACKING There exist a variety of problems for digital forensic investigators when applying any particular password cracking technique. One of these problems is estimation of the time taken to complete the cracking. As a result, it is a problem to estimate the cost of such an investigation. This section describes costing for password cracking and also discusses the importance of estimating costs for the purpose of password cracking in forensic investigations. 2.4.2 Costing Costing, or cost accounting, means the ―establishment of budgets, standard costs and actual costs of operations, processes, activities or products; and the analysis of variances, profitability, or the social use of funds‖ (Lucey, 2002, p.1). This subsection defines full cost and the two types of full costs, namely direct costs and indirect costs. 2.4.2.1 Full Cost 21
Full cost refers to the total amount of resources, measured in monetary terms, that are utilised to achieve a particular objective (Atrill, McLaney, Harvey, & Jenner, 2006). When units are not identical, costing is calculated on a job-by-job basis. Since every password to be cracked is different, each password would have to be cracked on a job-by-job basis. Therefore, the costs for cracking passwords should also be calculated on a job-by-job basis. In order to find out the cost of a particular unit of output (or job), all of the direct costs associated with producing that unit are assigned to it. Each of the units of output is then also charged with a fair share of indirect costs. This is known as job costing and is demonstrated in Figure 2.5 below (Atrill et al., 2006). Figure 2.5: Full cost of a job (Atrill, McLaney, Harvey & Jenner, 2006, p. 332) 2.4.2.2 Costs for Cracking a Password In the case of password cracking, the cost factors associated with cracking a password for each unit of output (i.e., each job) includes, but is not limited to the costs shown in Table 2.2. Table 2.2: Example of costs associated with password cracking Direct Costs Time Indirect Costs Power; computer and equipment depreciation. 22
Page 1 and 2: Cracking Passwords in Forensic Inve
Page 3 and 4: iii Acknowledgements This thesis wa
Page 5 and 6: v Abstract Digital Forensic Investi
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: i) Decryption attack: As discussed
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
Page 55 and 56: applications whose passwords need t
Page 57 and 58: equired for computing and testing.
Page 59 and 60: 3.2.3 The Research Questions and Hy
Page 61 and 62: main experiment, which is the next
Page 63 and 64: 12,500 x 8 = 100,000 passwords/seco
Page 65 and 66: 3.3.5 Data Map Figure 3.2: Research
Page 67 and 68: 4.0 INTRODUCTION Chapter 4 Research
Page 69 and 70: 4.1.2 Time Budgeting The time budge
Page 71 and 72: Another computer with the same conf
Page 73 and 74: minutes, and 24.8 days respectively
Page 75 and 76: vishal@vishal-desktop:~$ sudo addus
Page 77 and 78: Table 4.4: Monitoring/action-perfor
Page 79 and 80: 4.3 ANALYSIS OF DATA The experiment
Page 81 and 82: Table 4.6: First 10 accounts’ pas
Page 83 and 84: 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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