Reasoning Analytically About Password-Cracking Software Enze Alex - PowerPoint PPT Presentation

Reasoning Analytically About Password-Cracking Software Enze “Alex” Liu , Amanda Nakanishi, Maximilian Golla, David Cash, Blase Ur

Chic4go 2

Attack Model 80d561388725fa74f2d03cd16e1d687c 3

Attack Model 80d561388725fa74f2d03cd16e1d687c 1. h(“123456”) = e10adc3949ba59abbe56e057f20f883e 4

Attack Model 80d561388725fa74f2d03cd16e1d687c 1. h(“123456”) = e10adc3949ba59abbe56e057f20f883e 2. h(“password”) = 5f4dcc3b5aa765d61d8327deb882cf99 5

Attack Model 80d561388725fa74f2d03cd16e1d687c 1. h(“123456”) = e10adc3949ba59abbe56e057f20f883e 2. h(“password”) = 5f4dcc3b5aa765d61d8327deb882cf99 3. h(“monkey”) = d0763edaa9d9bd2a9516280e9044d885 6

Attack Model 80d561388725fa74f2d03cd16e1d687c 1. h(“123456”) = e10adc3949ba59abbe56e057f20f883e 2. h(“password”) = 5f4dcc3b5aa765d61d8327deb882cf99 3. h(“monkey”) = d0763edaa9d9bd2a9516280e9044d885 4. h(“letmein”) = 0d107d09f5bbe40cade3de5c71e9e9b7 7

Attack Model 80d561388725fa74f2d03cd16e1d687c 1. h(“123456”) = e10adc3949ba59abbe56e057f20f883e 2. h(“password”) = 5f4dcc3b5aa765d61d8327deb882cf99 3. h(“monkey”) = d0763edaa9d9bd2a9516280e9044d885 4. h(“letmein”) = 0d107d09f5bbe40cade3de5c71e9e9b7 5. h(“p@ssw0rd”) = 0f359740bd1cda994f8b55330c86d845 8

Attack Model 80d561388725fa74f2d03cd16e1d687c 1. h(“123456”) = e10adc3949ba59abbe56e057f20f883e 2. h(“password”) = 5f4dcc3b5aa765d61d8327deb882cf99 3. h(“monkey”) = d0763edaa9d9bd2a9516280e9044d885 4. h(“letmein”) = 0d107d09f5bbe40cade3de5c71e9e9b7 5. h(“p@ssw0rd”) = 0f359740bd1cda994f8b55330c86d845 6. h(“Chic4go”) = 80d561388725fa74f2d03cd16e1d687c 9

Chic4go 10

Chic4go Guess # 6 11

Chic4go Guess # 6 Guess # 13,545,239,432 12

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Password-Cracking Methods Probabilistic Models Software Tools 14

Password-Cracking Methods Probabilistic Models Software Tools Guess # Chic4go 15

Password-Cracking Methods Probabilistic Models Software Tools Guess # Chic4go 16

Guess Number by Enumeration 1. 123456 2. password 3. monkey Does Not Scale !!! 4. letmein 5. p@ssw0rd 6. Chic4go 17

Our Analysis Goals 1. Compute guess numbers efficiently 2. Configure guessing method systematically 18

Outline ● State of the art ● How software password-cracking tools work ● Our efficient techniques for guess numbers ● Our techniques for systematic configuration 19

Probabilistic Models Markov Models [Narayanan and Shmatikov, CCS 2005] Probabilistic Context-Free Grammars [Weir et al., S&P 2009] Neural Networks [Melicher et al., Usenix Security 2016] Guess # Configuration 20

Probabilistic Models Markov Models [Narayanan and Shmatikov, CCS 2005] Probabilistic Context-Free Grammars [Weir et al., S&P 2009] Neural Networks [Melicher et al., Usenix Security 2016] Guess # [CCS 2015] Configuration 21

Probabilistic Models Markov Models [Narayanan and Shmatikov, CCS 2005] Probabilistic Context-Free Grammars [Weir et al., S&P 2009] Neural Networks [Melicher et al., Usenix Security 2016] Guess # [CCS 2015] Configuration 22

Probabilistic Models Markov Models [Narayanan and Shmatikov, CCS 2005] Probabilistic Context-Free Grammars [Weir et al., S&P 2009] Neural Networks [Melicher et al., Usenix Security 2016] Guess # [CCS 2015] Configuration 23

Probabilistic Models Markov Models [Narayanan and Shmatikov, CCS 2005] Probabilistic Context-Free Grammars [Weir et al., S&P 2009] Neural Networks [Melicher et al., Usenix Security 2016] Guess-Efficient 24

Probabilistic Models Markov Models [Narayanan and Shmatikov, CCS 2005] Probabilistic Context-Free Grammars [Weir et al., S&P 2009] Neural Networks [Melicher et al., Usenix Security 2016] Guess-Efficient Wall-Clock Time Slow 25

Software Tools John the Ripper Hashcat 26

Software Tools chicdog chicagos chicago1 CHICAG chicago2 chicaga chicago chicago3 Chicago chicago6 CHICAGO chicago9 CHIcago 27

Software Tools John the Ripper Hashcat Guess-Inefficient Wall-Clock Time Fast 28

Software Tools John the Ripper Hashcat Guess-Inefficient Wall-Clock Time Fast 29

Software Tools John the Ripper Hashcat Guess # [S&P 2019] Configuration 30

Outline ● State of the art ● How software password-cracking tools work ● Our efficient techniques for guess numbers ● Our techniques for systematic configuration 31

Mangled Wordlist Attack 32

Mangled Wordlist Attack Wordlist Super Password Chicago 33

Mangled Wordlist Attack Wordlist Rulelist Super 1. Append “1” Password 2. Replace “a” → “4” Chicago 3. Lowercase all 34

Mangled Wordlist Attack Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Chicago 3. Lowercase all 35

Mangled Wordlist Attack Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all 36

Mangled Wordlist Attack Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all Chicago1 37

Mangled Wordlist Attack Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all Chicago1 Super P4ssword Chic4go 38

Mangled Wordlist Attack Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all Chicago1 Super P4ssword Chic4go super password chicago 39

Example Wordlists and Rulelists Wordlist PGS ( ≈ 20,000,000) Linkedin ( ≈ 60,000,000) HIBP ( ≈ 500,000,000) 40

Example Wordlists and Rulelists Wordlist Rulelist PGS ( ≈ 20,000,000) Korelogic ( ≈ 5,000) Linkedin ( ≈ 60,000,000) Megatron ( ≈ 15,000) HIBP ( ≈ 500,000,000) Generated2 ( ≈ 65,000) 41

Example Wordlists and Rulelists Wordlist Rulelist 10 9 - 10 15 PGS ( ≈ 20,000,000) Korelogic ( ≈ 5,000) guesses Linkedin ( ≈ 60,000,000) Megatron ( ≈ 15,000) HIBP ( ≈ 500,000,000) Generated2 ( ≈ 65,000) 42

Example Wordlists and Rulelists Wordlist Rulelist 10 9 - 10 15 PGS ( ≈ 20,000,000) Korelogic ( ≈ 5,000) guesses Linkedin ( ≈ 60,000,000) Megatron ( ≈ 15,000) HIBP ( ≈ 500,000,000) Generated2 ( ≈ 65,000) + Hackers’ private word/rule lists 43

Outline ● State of the art ● How software password-cracking tools work ● Our efficient techniques for guess numbers ● Our techniques for systematic configuration 44

Is This Password in the Guesses? Guesses Super1 Password1 Chic4go Chicago1 Super P4ssword Chic4go super password chicago 45

Is This Password in the Guesses? Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all Chicago1 Super P4ssword Chic4go super password chicago 46

Insight We can work backwards! 47

Insight: Invert Rules Password Chic4go 48

Insight: Invert Rules Rulelist Password 1. Append “1” Chic4go 2. Replace “a” → “4” 3. Lowercase all 49

Insight: Invert Rules Rulelist Password 1. Append “1” Chic4go 2. Replace “a” → “4” 3. Lowercase all 50

Insight: Invert Rules Preimages Rulelist Password Chicago 1. Append “1” Chic4go 2. Replace “a” → “4” Chic4go 3. Lowercase all 51

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*05 O03 d '7 Switch the first and the sixth char; Delete the first three chars; Duplicate the whole word; Truncate the word to length 7; Preimages? Preimages? Chic4go 53

Where in the Stream? Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all Chicago1 Super P4ssword Chic4go 54

Where in the Stream? Wordlist Rulelist Guesses Super 1. Append “1” Super1 Password 2. Replace “a” → “4” Password1 Chicago 3. Lowercase all Chicago1 Super P4ssword Chic4go 55

Counting Guesses For Each Rule Wordlist Rule Guesses Reject if no “a”; Super 2 Password Replace a → 4 Chicago 56

Our First Contribution ● Fast Guess Number Estimation 57

Fast Guess Number Estimation Linkedin + SpiderLab 58

Fast Guess Number Estimation Linkedin + SpiderLab Guesses 59

Fast Guess Number Estimation Linkedin + SpiderLab Guesses Enumeration Our Approach Size ~ 3 PB ~ 10 GB 60

Fast Guess Number Estimation Linkedin + SpiderLab Guesses Enumeration Our Approach Size ~ 3 PB ~ 10 GB Preprocessing > 2 years < 1 day 61

Fast Guess Number Estimation Linkedin + SpiderLab Guesses Enumeration Our Approach Size ~ 3 PB ~ 10 GB Preprocessing > 2 years < 1 day Mean Lookup ??? < 1 second 62

Outline ● State of the art ● How software password-cracking tools work ● Our efficient techniques for guess numbers ● Our techniques for systematic configuration 63

Software Tools Depend On ● Order of rules ● Contents of the rulelist ● Order of words ● Contents of the wordlist 64