Hao Xu; Title: Improving Rainbow Table Cracking Accuracy; Mentor(S): Xianping Wang, CITG

Total Page：16

File Type：pdf, Size：1020Kb

Student(s): Hao Xu; Title: Improving Rainbow Table Cracking Accuracy; Mentor(s): Xianping Wang, CITG. Abstract: Password cracking is the process of recovering plaintext passwords from data that has been stored in or transmitted by computing systems in cryptanalysis, computer security and digital forensics. There are many situations that require password cracking: helping users recover forgotten passwords, gaining unauthorized access to systems, checking password strength, etc. The most popular and applicable password cracking method is brute-force attack with various improvements such as dictionary attack, rainbow table attack. Usually they are accelerated with GPU, FPGA and ASIC. As passwords are usually stored in their hash codes instead of plaintext. to accelerate the password cracking process, caching the output of cryptographic hash codes of passwords, named as rainbow table, are used widely today. However, rainbow tables are usually created from exhaustive password dictionaries, in which many unusual combinations of letters, symbols and digits are contained, which decreased cracking efficiency and accuracy The efficiency and accuracy of rainbow table cracking can be improved from many aspects such as password patterns, computing engines, etc. In this research, we will employ many openly available leaked passwords, to find their distribution by maximum likelihood estimation, design a password generator based on the found distribution, generate rainbow tables on the passwords generated by the designed password generator. The accuracy of our rainbow table cracker will be compared with several popular password crackers --- John the Ripper password cracker, Cain and Abel, Hashcat , and Ophcrack " .

Copy Link

Recommended publications

GPU-Based Password Cracking on the Security of Password Hashing Schemes Regarding Advances in Graphics Processing Units
Radboud University Nijmegen Faculty of Science Kerckhoffs Institute Master of Science Thesis GPU-based Password Cracking On the Security of Password Hashing Schemes regarding Advances in Graphics Processing Units by Martijn Sprengers [email protected] Supervisors: Dr. L. Batina (Radboud University Nijmegen) Ir. S. Hegt (KPMG IT Advisory) Ir. P. Ceelen (KPMG IT Advisory) Thesis number: 646 Final Version Abstract Since users rely on passwords to authenticate themselves to computer systems, ad- versaries attempt to recover those passwords. To prevent such a recovery, various password hashing schemes can be used to store passwords securely. However, recent advances in the graphics processing unit (GPU) hardware challenge the way we have to look at secure password storage. GPU's have proven to be suitable for crypto- graphic operations and provide a significant speedup in performance compared to traditional central processing units (CPU's). This research focuses on the security requirements and properties of prevalent pass- word hashing schemes. Moreover, we present a proof of concept that launches an exhaustive search attack on the MD5-crypt password hashing scheme using modern GPU's. We show that it is possible to achieve a performance of 880 000 hashes per second, using different optimization techniques. Therefore our implementation, executed on a typical GPU, is more than 30 times faster than equally priced CPU hardware. With this performance increase, `complex' passwords with a length of 8 characters are now becoming feasible to crack. In addition, we show that between 50% and 80% of the passwords in a leaked database could be recovered within 2 months of computation time on one Nvidia GeForce 295 GTX.
[Show full text]
Truecrack Bruteforcing Per Volumi Truecrypt
Luca Vaccaro http://code.google.com/p/truecrack/ [email protected] User development guide. TrueCrypt © . software application used for on-the-fly encryption (OTFE). TrueCrack . bruteforce password cracker for TrueCrypt © (Copyrigth) volume files, optimazed with Nvidia Cuda technology. This software is Based on TrueCrypt, freely available athttp://www.truecrypt.org/ Master key . Crypt the volume of data. Generated one time in the volume creation phase from random value. Write inside the header section of the volume file. Header key . Crypt the header section of the volume file. Generated from a user password and a random salt (64 bytes). The salt is write in plain text in the first 64 bytes of volume file. Hard disk encryption: . Standard block cipher: XTS . Hash availables: AES, Serpent, Twofish . Default: AES Key derivation function: . Standard algorithm: PBKDF2 . Hash availables: RIPEMD160, SHA-512, Whirpool . Default: RIPEMD160 Master Header Key Key Plain Cipher Volume data data + file header Opening a TrueCrypt volume means to retrieve the Master Key from the Header section In the Header there are some fields (true, crc32) for checking the success of the decipher operation . If the password is right or wrong Header key User password salt Volume Master file key CUDA or Compute Unified Device Architecture is a parallel computing architecture developed by Nvidia. CUDA gives developers access to the virtual instruction set and memory of the parallel computational elements in CUDA GPUs. Each GPU is a collection of multicores. Each core can run mmore cuda «block», and each block can run a numbers of parallel «thread» 1. Level of parallilism : block 2.
[Show full text]
Study on Massive-Scale Slow-Hash Recovery Using Unified
S S symmetry Article Study on Massive-Scale Slow-Hash Recovery Using Unified Probabilistic Context-Free Grammar and Symmetrical Collaborative Prioritization with Parallel Machines Tianjun Wu 1,*,†, Yuexiang Yang 1,†, Chi Wang 2,† and Rui Wang 2,† 1 College of Computer, National University of Defense Technology, Changsha 410073, China; [email protected] 2 VeriClouds Co., Seattle, WA 98105, USA; [email protected] (C.W.); [email protected] (R.W.) * Correspondence: [email protected]; Tel.: +86-13-54-864-2846 † The authors contribute equally to this work and are co-first authors. Received: 23 February 2019; Accepted: 26 March 2019; Published: 1 April 2019 Abstract: Slow-hash algorithms are proposed to defend against traditional offline password recovery by making the hash function very slow to compute. In this paper, we study the problem of slow-hash recovery on a large scale. We attack the problem by proposing a novel concurrent model that guesses the target password hash by leveraging known passwords from a largest-ever password corpus. Previously proposed password-reused learning models are specifically designed for targeted online guessing for a single hash and thus cannot be efficiently parallelized for massive-scale offline recovery, which is demanded by modern hash-cracking tasks. In particular, because the size of a probabilistic context-free grammar (PCFG for short) model is non-trivial and keeping track of the next most probable password to guess across all global accounts is difficult, we choose clever data structures and only expand transformations as needed to make the attack computationally tractable. Our adoption of max-min heap, which globally ranks weak accounts for both expanding and guessing according to unified PCFGs and allows for concurrent global ranking, significantly increases the hashes can be recovered within limited time.
[Show full text]
Analysis of Password Cracking Methods & Applications
The University of Akron IdeaExchange@UAkron The Dr. Gary B. and Pamela S. Williams Honors Honors Research Projects College Spring 2015 Analysis of Password Cracking Methods & Applications John A. Chester The University Of Akron, [email protected] Please take a moment to share how this work helps you through this survey. Your feedback will be important as we plan further development of our repository. Follow this and additional works at: http://ideaexchange.uakron.edu/honors_research_projects Part of the Information Security Commons Recommended Citation Chester, John A., "Analysis of Password Cracking Methods & Applications" (2015). Honors Research Projects. 7. http://ideaexchange.uakron.edu/honors_research_projects/7 This Honors Research Project is brought to you for free and open access by The Dr. Gary B. and Pamela S. Williams Honors College at IdeaExchange@UAkron, the institutional repository of The nivU ersity of Akron in Akron, Ohio, USA. It has been accepted for inclusion in Honors Research Projects by an authorized administrator of IdeaExchange@UAkron. For more information, please contact [email protected], [email protected]. Analysis of Password Cracking Methods & Applications John A. Chester The University of Akron Abstract -- This project examines the nature of password cracking and modern applications. Several applications for different platforms are studied. Different methods of cracking are explained, including dictionary attack, brute force, and rainbow tables. Password cracking across different mediums is examined. Hashing and how it affects password cracking is discussed. An implementation of two hash-based password cracking algorithms is developed, along with experimental results of their efficiency. I. Introduction Password cracking is the process of either guessing or recovering a password from stored locations or from a data transmission system [1].
[Show full text]
Password Cracking Using Cain & Abel
Password Cracking Using Cain & Abel Learning Objectives: This exercise demonstrates how password could be cracked through various methods, specifically regarding MD5 encrypted passwords. Summary: You will use Cain & Abel for this exercise. Deliverables: Submit a lab report by answering the review questions. In some review questions, you may provide screen captures. Dictionary attack Dictionary attack uses a predetermined list of words from a dictionary to generate possible passwords that may match the MD5 encrypted password. This is one of the easiest and quickest way to obtain any given password. 1. Start Cain & Abel via the Desktop Shortcut ‘Cain’ or Start menu. a. (Start > Programs > Cain > Cain). 2. Choose ‘Yes’ to proceed when a ‘User Account Control’ notification pops up regarding software authorization. 3. Once on, select the ‘Cracker’ tab with the key symbol, then click on MD5 Hashes. The result should look like the image below. 1 Collaborative Virtual Computer Lab (CVCLAB) Penn State Berks 4. As you might have noticed we don’t have any passwords to crack, thus for the next few steps we will create our own MD5 encrypted passwords. First, locate the Hash Calculator among a row of icons near the top. Open it. 5. Next, type into ‘Text to Hash’ the word password. It will generate a list of hashes pertaining to different types of hash algorithms. We will be focusing on MD5 hash so copy it. Then exit calculator by clicking ‘Cancel’ (Fun Fact: Hashes are case sensitive so any slight changes to the text will change the hashes generated, try changing a letter or two and you will see.
[Show full text]
User Authentication and Cryptographic Primitives
User Authentication and Cryptographic Primitives Brad Karp UCL Computer Science CS GZ03 / M030 16th November 2016 Outline • Authenticating users – Local users: hashed passwords – Remote users: s/key – Unexpected covert channel: the Tenex password- guessing attack • Symmetric-key-cryptography • Public-key cryptography usage model • RSA algorithm for public-key cryptography – Number theory background – Algorithm definition 2 Dictionary Attack on Hashed Password Databases • Suppose hacker obtains copy of password file (until recently, world-readable on UNIX) • Compute H(x) for 50K common words • String compare resulting hashed words against passwords in file • Learn all users’ passwords that are common English words after only 50K computations of H(x)! • Same hashed dictionary works on all password files in world! 3 Salted Password Hashes • Generate a random string of bytes, r • For user password x, store [H(r,x), r] in password file • Result: same password produces different result on every machine – So must see password file before can hash dictionary – …and single hashed dictionary won’t work for multiple hosts • Modern UNIX: password hashes salted; hashed password database readable only by root 4 Salted Password Hashes • Generate a random string of bytes, r Dictionary• For user password attack still x, store possible [H(r,x after), r] in attacker seespassword password file file! Users• Result: should same pick password passwords produces that different aren’t result close to ondictionary every machine words. – So must see password file
[Show full text]
Attack Frameworks and Tools
Network Architectures and Services, Georg Carle Faculty of Informatics Technische Universität München, Germany Attack Frameworks and Tools Pranav Jagdish Betreuer: Nadine Herold Seminar Innovative Internet Technologies and Mobile Communication WS2014 Lehrstuhl Netzarchitekturen und Netzdienste Fakultät für Informatik, Technische Universität München Overview Introduction Overview of Tools Password Crackers Network Poisoners Network Security Tools Denial of Service Tools Concluding remarks AttackTitel Frameworks and Tools 2 Introduction Network Security – perhaps the most important aspect of communications in todays world How easy it is to attack a target system or network today? . Tools automate most of the work . From fingerprinting your target to attacking . Knowledge requirements decrease day by day AttackTitel Frameworks and Tools 3 Introduction The CIA Triangle Confidentiality Integrity Availability AttackTitel Frameworks and Tools 4 Overview of the Tools Password Crackers • Free • Free • Free • Windows • Various • Linux, Only GUI Platforms OSX and Hashcat Windows Cain and Abel and Cain John the Ripper John AttackTitel Frameworks and Tools 5 Overview of the Tools Network Poisoners • Free • Free • Python • Various ZARP Script Platforms Ettercap AttackTitel Frameworks and Tools 6 Overview of the Tools Network Security Tools • Free • Free • Free • Various (Signup • Python Nmap Platforms Required) Script • Windows Sqlmap Metasploit and Linux AttackTitel Frameworks and Tools 7 Overview of the Tools Denial of Service Tools • Free • Free • Windows • Python LOIC Only GUI HULK Script AttackTitel Frameworks and Tools 8 Password Crackers Attack: Confidentiality Crack passwords or keys Crack various kind of hashes Initially used to crack local system passwords like for Windows and Linux Have extended to include numerous kinds of hashes New versions are faster and use different kind of cracking methods .
[Show full text]
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms Levent Ertaul, Manpreet Kaur, Venkata Arun Kumar R Gudise CSU East Bay, Hayward, CA, USA. [email protected], [email protected], [email protected] Abstract- With the increase in mobile wireless or data lookup. Whereas, Cryptographic hash functions are technologies, security breaches are also increasing. It has used for building blocks for HMACs which provides become critical to safeguard our sensitive information message authentication. They ensure integrity of the data from the wrongdoers. So, having strong password is that is transmitted. Collision free hash function is the one pivotal. As almost every website needs you to login and which can never have same hashes of different output. If a create a password, it’s tempting to use same password and b are inputs such that H (a) =H (b), and a ≠ b. for numerous websites like banks, shopping and social User chosen passwords shall not be used directly as networking websites. This way we are making our cryptographic keys as they have low entropy and information easily accessible to hackers. Hence, we need randomness properties [2].Password is the secret value from a strong application for password security and which the cryptographic key can be generated. Figure 1 management. In this paper, we are going to compare the shows the statics of increasing cybercrime every year. Hence performance of 3 key derivation algorithms, namely, there is a need for strong key generation algorithms which PBKDF2 (Password Based Key Derivation Function), can generate the keys which are nearly impossible for the Bcrypt and Scrypt.
[Show full text]
Hash Crack: Password Cracking Manual
Hash Crack. Copyright © 2017 Netmux LLC All rights reserved. Without limiting the rights under the copyright reserved above, no part of this publication may be reproduced, stored in, or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without prior written permission. ISBN-10: 1975924584 ISBN-13: 978-1975924584 Netmux and the Netmux logo are registered trademarks of Netmux, LLC. Other product and company names mentioned herein may be the trademarks of their respective owners. Rather than use a trademark symbol with every occurrence of a trademarked name, we are using the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The information in this book is distributed on an “As Is” basis, without warranty. While every precaution has been taken in the preparation of this work, neither the author nor Netmux LLC, shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in it. While every effort has been made to ensure the accuracy and legitimacy of the references, referrals, and links (collectively “Links”) presented in this book/ebook, Netmux is not responsible or liable for broken Links or missing or fallacious information at the Links. Any Links in this book to a specific product, process, website, or service do not constitute or imply an endorsement by Netmux of same, or its producer or provider. The views and opinions contained at any Links do not necessarily express or reflect those of Netmux.
[Show full text]
Optimizing a Password Hashing Function with Hardware-Accelerated Symmetric Encryption
S S symmetry Article Optimizing a Password Hashing Function with Hardware-Accelerated Symmetric Encryption Rafael Álvarez 1,* , Alicia Andrade 2 and Antonio Zamora 3 1 Departamento de Ciencia de la Computación e Inteligencia Artificial (DCCIA), Universidad de Alicante, 03690 Alicante, Spain 2 Fac. Ingeniería, Ciencias Físicas y Matemática, Universidad Central, Quito 170129, Ecuador; [email protected] 3 Departamento de Ciencia de la Computación e Inteligencia Artificial (DCCIA), Universidad de Alicante, 03690 Alicante, Spain; [email protected] * Correspondence: [email protected] Received: 2 November 2018; Accepted: 22 November 2018; Published: 3 December 2018 Abstract: Password-based key derivation functions (PBKDFs) are commonly used to transform user passwords into keys for symmetric encryption, as well as for user authentication, password hashing, and preventing attacks based on custom hardware. We propose two optimized alternatives that enhance the performance of a previously published PBKDF. This design is based on (1) employing a symmetric cipher, the Advanced Encryption Standard (AES), as a pseudo-random generator and (2) taking advantage of the support for the hardware acceleration for AES that is available on many common platforms in order to mitigate common attacks to password-based user authentication systems. We also analyze their security characteristics, establishing that they are equivalent to the security of the core primitive (AES), and we compare their performance with well-known PBKDF algorithms, such as Scrypt and Argon2, with favorable results. Keywords: symmetric; encryption; password; hash; cryptography; PBKDF 1. Introduction Key derivation functions are employed to obtain one or more keys from a master secret. This is especially useful in the case of user passwords, which can be of arbitrary length and are unsuitable to be used directly as fixed-size cipher keys, so, there must be a process for converting passwords into secret keys.
[Show full text]
NCL Password Cracking--Key Getting Started You Can Install a Pre-Built Vmware VM from Here
NCL Password Cracking--Key Getting Started You can install a pre-built VMware VM from here. You just need to open the VM, not install it. The login credentials are kali, kali. https://www.offensive-security.com/kali-linux-vm-vmware-virtualbox-image-download/ Then read this excellent blog from NCL. https://cryptokait.com/2019/09/24/everything-you-need-to-know-about-password-cracking-for-the- national-cyber-league-games/ A Note about Hashcat Hashcat, and the older John the Ripper, keep a list of hashes they have already cracked. If the hash is in the list, it will not appear in the output. This can be confusing if you are having problems and run the same hash file repeatedly. If you think some cracked hashes are missing, look in .hashcat/hashcat.potfile in your home directory, or perhaps where you ran hashcat from. If you want to start from scratch, just delete .hashcat/hashcat.potfile A Crack to Start With This is from the paragraph in the NCL Blog, “Using a Pre-Made Wordlist on Kali.” Follow the procedure to unzip (actually Gnu unzip or gunzip) the password list from the rockyou.com breach (I moved rockyou.txt to my home directory instead of Downloads.) Then run the hashcat line, hashcat -m 0 {means the hashes are MD5} -a 0 {attack will be wordlist only} -o outputfile {where the output goes} hashlist pwlist Here are the hashes. 8549137cd494c22ae87eef3e18a46986 0f96a320a8c0bf7e3f6d375b0d9d3a4c 1a8cb8d148b513dfa1d285077fc4e3fb 22a313110bf5b84c0a58eecc27deaa30 e4fd50109f0e40e8c1a895d8e5c71199 These are easy and should crack in under a minute. Solution Save the hashes in a file on Kali.
[Show full text]
Key Derivation Functions and Their GPU Implementation
MASARYK UNIVERSITY FACULTY}w¡¢£¤¥¦§¨ OF I !"#$%&'()+,-./012345<yA|NFORMATICS Key derivation functions and their GPU implementation BACHELOR’S THESIS Ondrej Mosnáˇcek Brno, Spring 2015 This work is licensed under a Creative Commons Attribution- NonCommercial-ShareAlike 4.0 International License. https://creativecommons.org/licenses/by-nc-sa/4.0/ cbna ii Declaration Hereby I declare, that this paper is my original authorial work, which I have worked out by my own. All sources, references and literature used or excerpted during elaboration of this work are properly cited and listed in complete reference to the due source. Ondrej Mosnáˇcek Advisor: Ing. Milan Brož iii Acknowledgement I would like to thank my supervisor for his guidance and support, and also for his extensive contributions to the Cryptsetup open- source project. Next, I would like to thank my family for their support and pa- tience and also to my friends who were falling behind schedule just like me and thus helped me not to panic. Last but not least, access to computing and storage facilities owned by parties and projects contributing to the National Grid In- frastructure MetaCentrum, provided under the programme “Projects of Large Infrastructure for Research, Development, and Innovations” (LM2010005), is also greatly appreciated. v Abstract Key derivation functions are a key element of many cryptographic applications. Password-based key derivation functions are designed speciﬁcally to derive cryptographic keys from low-entropy sources (such as passwords or passphrases) and to counter brute-force and dictionary attacks. However, the most widely adopted standard for password-based key derivation, PBKDF2, as implemented in most applications, is highly susceptible to attacks using Graphics Process- ing Units (GPUs).
[Show full text]