Showing papers on "Password strength published in 2017"

Design and Evaluation of a Data-Driven Password Meter

Abstract: Despite their ubiquity, many password meters provide inaccurate strength estimates. Furthermore, they do not explain to users what is wrong with their password or how to improve it. We describe the development and evaluation of a data-driven password meter that provides accurate strength measurement and actionable, detailed feedback to users. This meter combines neural networks and numerous carefully combined heuristics to score passwords and generate data-driven text feedback about the user's password. We describe the meter's iterative development and final design. We detail the security and usability impact of the meter's design dimensions, examined through a 4,509-participant online study. Under the more common password-composition policy we tested, we found that the data-driven meter with detailed feedback led users to create more secure, and no less memorable, passwords than a meter with only a bar as a strength indicator.

Let's Go in for a Closer Look: Observing Passwords in Their Natural Habitat

Abstract: Text passwords---a frequent vector for account compromise, yet still ubiquitous---have been studied for decades by researchers attempting to determine how to coerce users to create passwords that are hard for attackers to guess but still easy for users to type and memorize. Most studies examine one password or a small number of passwords per user, and studies often rely on passwords created solely for the purpose of the study or on passwords protecting low-value accounts. These limitations severely constrain our understanding of password security in practice, including the extent and nature of password reuse, password behaviors specific to categories of accounts (e.g., financial websites), and the effect of password managers and other privacy tools. In this paper we report on an in situ study of 154 participants over an average of 147 days each. Participants' computers were instrumented---with careful attention to privacy---to record detailed information about password characteristics and usage, as well as man other computing behaviors such as use of security and privacy web browser extensions. This data allows a more accurate analysis of password characteristics and behaviors across the full range of participants' web-based accounts. Examples of our findings are that the use of symbols and digits in passwords predicts increased likelihood of reuse, while increased password strength predicts decreased likelihood of reuse; that password reuse is more prevalent than previously believed, especially when partial reuse is taken into account; and that password managers may have no impact on password reuse or strength. We also observe that users can be grouped into a handful of behavioral clusters, representative of various password management strategies. Our findings suggest that once a user needs to manage a larger number of passwords, they cope by partially and exactly reusing passwords across most of their accounts.

Zero-Sum Password Cracking Game: A Large-Scale Empirical Study on the Crackability, Correlation, and Security of Passwords

Abstract: In this paper, we conduct a large-scale study on the crackability, correlation, and security of ${\sim}145$ million real world passwords, which were leaked from several popular Internet services and applications. To the best of our knowledge, this is the largest empirical study that has been conducted. Specifically, we first evaluate the crackability of ${\sim}145$ million real world passwords against 6+ state-of-the-art password cracking algorithms in multiple scenarios. Second, we examine the effectiveness and soundness of popular commercial password strength meters (e.g., Google, QQ) and the security impacts of username/email leakage on passwords. Finally, we discuss the implications of our results, analysis, and findings, which are expected to help both password users and system administrators to gain a deeper understanding of the vulnerability of real passwords against state-of-the-art password cracking algorithms, as well as to shed light on future password security research topics.

The Password Reset MitM Attack

Abstract: We present the password reset MitM (PRMitM) attack and show how it can be used to take over user accounts. The PRMitM attack exploits the similarity of the registration and password reset processes to launch a man in the middle (MitM) attack at the application level. The attacker initiates a password reset process with a website and forwards every challenge to the victim who either wishes to register in the attacking site or to access a particular resource on it. The attack has several variants, including exploitation of a password reset process that relies on the victim's mobile phone, using either SMS or phone call. We evaluated the PRMitM attacks on Google and Facebook users in several experiments, and found that their password reset process is vulnerable to the PRMitM attack. Other websites and some popular mobile applications are vulnerable as well. Although solutions seem trivial in some cases, our experiments show that the straightforward solutions are not as effective as expected. We designed and evaluated two secure password reset processes and evaluated them on users of Google and Facebook. Our results indicate a significant improvement in the security. Since millions of accounts are currently vulnerable to the PRMitM attack, we also present a list of recommendations for implementing and auditing the password reset process.

An Improved and Secure Anonymous Biometric-Based User Authentication with Key Agreement Scheme for the Integrated EPR Information System

Abstract: Nowadays, many hospitals and medical institutes employ an authentication protocol within electronic patient records (EPR) services in order to provide protected electronic transactions in e-medicine systems. In order to establish efficient and robust health care services, numerous studies have been carried out on authentication protocols. Recently, Li et al. proposed a user authenticated key agreement scheme according to EPR information systems, arguing that their scheme is able to resist various types of attacks and preserve diverse security properties. However, this scheme possesses critical vulnerabilities. First, the scheme cannot prevent off-line password guessing attacks and server spoofing attack, and cannot preserve user identity. Second, there is no password verification process with the failure to identify the correct password at the beginning of the login phase. Third, the mechanism of password change is incompetent, in that it induces inefficient communication in communicating with the server to change a user password. Therefore, we suggest an upgraded version of the user authenticated key agreement scheme that provides enhanced security. Our security and performance analysis shows that compared to other related schemes, our scheme not only improves the security level, but also ensures efficiency.

Diversify to survive: making passwords stronger with adaptive policies

Abstract: Password-composition policies are intended to increase resistance to guessing attacks by requiring certain features (e.g., a minimum length and the inclusion of a digit). Sadly, they often result in users' passwords exhibiting new, yet still predictable, patterns. In this paper, we investigate the usability and security of adaptive password-composition policies, which dynamically change password requirements over time as users create new passwords. We conduct a 2,619- participant between-subjects online experiment to evaluate the strength and usability of passwords created with two adaptive password policies. We also design and test a feedback system that guides users to successfully create a password conforming to these policies. We find that a well-configured, structure-based adaptive password policy can significantly increase password strength with little to no decrease in usability. We discuss how system administrators can use these results to improve password diversity.

A New Multimodal Approach for Password Strength Estimation—Part I: Theory and Algorithms

Abstract: After more than two decades of research in the field of password strength estimation, one clear conclusion may be drawn: no password strength metric by itself is better than all other metrics for every possible password. Building upon this certainty and also taking advantage of the knowledge gained in the area of information fusion, in this paper, we propose a novel multimodal strength metric that combines several imperfect individual metrics to benefit from their strong points in order to overcome many of their weaknesses. The final multimodal metric comprises different modules based both on heuristics and statistics, which, after their fusion, succeed to provide in real time a realistic and reliable feedback regarding the “guessability” of passwords. The validation protocol and the test results are presented and discussed in a companion paper.

SPHINX: A Password Store that Perfectly Hides Passwords from Itself

Abstract: Password managers (aka stores or vaults) allow a user to store and retrieve (usually high-entropy) passwords for her multiple password-protected services by interacting with a "device" serving the role of the manager (e.g., a smartphone or an online third-party service) on the basis of a single memorable (low-entropy) master password. Existing password managers work well to defeat offline dictionary attacks upon web service compromise, assuming the use of high-entropy passwords is enforced. However, they are vulnerable to leakage of all passwords in the event the device is compromised, due to the need to store the passwords encrypted under the master password and/or the need to input the master password to the device (as in smartphone managers). Evidence exists that password managers can be attractive attack targets. In this paper, we introduce a novel approach to password management, called SPHINX, which remains secure even when the password manager itself has been compromised. In SPHINX, the information stored on the device is information theoretically independent of the user's master password - an attacker breaking into the device learns no information about the master password or the user's site-specific passwords. Moreover, an attacker with full control of the device, even at the time the user interacts with it, learns nothing about the master password - the password is not entered into the device in plaintext form or in any other way that may leak information on it. Unlike existing managers, SPHINX produces strictly high-entropy passwords and makes it compulsory for the users to register these randomized passwords with the web services, hence fully defeating offline dictionary attack upon service compromise. The design and security of SPHINX is based on the device-enhanced PAKE model of Jarecki et al. that provides the theoretical basis for this construction and is backed by rigorous cryptographic proofs of security. While SPHINX is suitable for different device and online platforms, in this paper, we report on its concrete instantiation on smartphones given their popularity and trustworthiness as password managers (or even two-factor authentication). We present the design, implementation and performance evaluation of SPHINX, offering prototype browser plugins, smartphone apps and transparent device-client communication. Based on our inspection analysis, the overall user experience of SPHINX improves upon current managers. We also report on a lab-based usability study of SPHINX, which indicates that users' perception of SPHINX security and usability is high and satisfactory when compared to regular password-based authentication. Finally, we discuss how SPHINX may be extended to an online service for the purpose of back-up or as an independent password manager.

A lightweight password-based authentication protocol using smart card

Abstract: Summary With its simplicity and feasibility, password-based remote user authentication becomes a popular way to control remote access to network. These years, numerous password-based authentication schemes have been proposed. Recently, Maitra et al proposed a smart card–based scheme which claims to be resistant to various attacks. Unfortunately, we found some important flaws in this scheme. Therefore, in this paper, we will demonstrate that the scheme of Maitra et al is not secure enough as claimed: neither resisting against off-line password guessing attack and insider attack nor preserve forward secrecy. To overcome those flaws, we put forward an improved new scheme which not only is resistant to all known attacks but also provides many attractive attributes, such as user revocation and re-register. Also, we compared the scheme with other related schemes, the result proved the superiority of our scheme. Particularly, we show a new way (beyond the conventional Deffie-Hellman approach) to achieve forward secrecy. Furthermore, we put some efforts into exploring the design principle of authentication schemes.

Studying the Impact of Managers on Password Strength and Reuse

Abstract: Despite their well-known security problems, passwords are still the incumbent authentication method for virtually all online services. To remedy the situation, end-users are very often referred to password managers as a solution to the password reuse and password weakness problems. However, to date the actual impact of password managers on password security and reuse has not been studied systematically. In this paper, we provide the first large-scale study of the password managers' influence on users' real-life passwords. From 476 participants of an online survey on users' password creation and management strategies, we recruit 170 participants that allowed us to monitor their passwords in-situ through a browser plugin. In contrast to prior work, we collect the passwords' entry methods (e.g., human or password manager) in addition to the passwords and their metrics. Based on our collected data and our survey, we gain a more complete picture of the factors that influence our participants' passwords' strength and reuse. We quantify for the first time that password managers indeed benefit the password strength and uniqueness, however, also our results also suggest that those benefits depend on the users' strategies and that managers without password generators rather aggravate the existing problems.

Comments on “An improved secure and efficient password and chaos-based two-party key agreement protocol”

Abstract: Recently, Liu and Xue proposed a secure two-party password-based authenticated key exchange protocol by utilizing the semi-group property of the Chebyshev chaotic maps. We exploit the vulnerability of the protocol in this paper by illustrating an off-line password guessing attack. In this attack, the password of a honest user will be recover by an attacker without being noticed by the server or the victim. To overcome such problem, we propose a simple and compatible fix.

A Secure and Efficient One-time Password Authentication Scheme for WSN

Abstract: An algorithm that a user has authenticated over remote devices should be designed to consider the limitations of computation and lower power in a wireless sensor net- works. Lamport first proposed a one-time password authentication scheme which the password was different in each transaction. In this paper, according to the Lam- port's concept we propose an efficient and secure one- time password authentication scheme for wireless sensor networks.

Improvement of Efficient and Secure Smart Card Based Password Authentication Scheme.

Abstract: Remote user authentication scheme is one of the most convenient authentication schemes to deal with secret data over public communication channel. In order to satisfy the security requirements, the smart card has become an essential device, one that is widely used. This is because its low computational cost and expedient portability. Recently, Liu et al. pointed out some security weaknesses in Li et al.’s scheme, such as man-in-the middle attack and insider attack. They hence claimed that their scheme is more secure and practical remote user authentication scheme. However, we find that Liu et al.’s scheme is still insecure against outsider attack and offline password guessing attack. To overcome these security vulnerabilities, we propose a new authentication and key agreement scheme using smart card. In addition, we demonstrate that proposed authentication scheme has strong resistance to the various attacks. Finally, we compare the performance and functionality of the proposed scheme with other related schemes.

PassGAN: A Deep Learning Approach for Password Guessing

Abstract: State-of-the-art password guessing tools, such as HashCat and John the Ripper, enable users to check billions of passwords per second against password hashes. In addition to performing straightforward dictionary attacks, these tools can expand password dictionaries using password generation rules, such as concatenation of words (e.g., "password123456") and leet speak (e.g., "password" becomes "p4s5w0rd"). Although these rules work well in practice, expanding them to model further passwords is a laborious task that requires specialized expertise. To address this issue, in this paper we introduce PassGAN, a novel approach that replaces human-generated password rules with theory-grounded machine learning algorithms. Instead of relying on manual password analysis, PassGAN uses a Generative Adversarial Network (GAN) to autonomously learn the distribution of real passwords from actual password leaks, and to generate high-quality password guesses. Our experiments show that this approach is very promising. When we evaluated PassGAN on two large password datasets, we were able to surpass rule-based and state-of-the-art machine learning password guessing tools. However, in contrast with the other tools, PassGAN achieved this result without any a-priori knowledge on passwords or common password structures. Additionally, when we combined the output of PassGAN with the output of HashCat, we were able to match 51%-73% more passwords than with HashCat alone. This is remarkable, because it shows that PassGAN can autonomously extract a considerable number of password properties that current state-of-the art rules do not encode.

Password-Hashing Status

Abstract: Computers are used in our everyday activities, with high volumes of users accessing provided services. One-factor authentication consisting of a username and a password is the common choice to authenticate users in the web. However, the poor password management practices are exploited by attackers that disclose the users’ credentials, harming both users and vendors. In most of these occasions the user data were stored in clear or were just processed by a cryptographic hash function. Password-hashing techniques are applied to fortify this user-related information. The standardized primitive is currently the PBKDF2 while other widely-used schemes include Bcrypt and Scrypt. The evolution of parallel computing enables several attacks in password-hash cracking. The international cryptographic community conducted the Password Hashing Competition (PHC) to identify new efficient and more secure password-hashing schemes, suitable for widespread adoption. PHC advanced our knowledge of password-hashing. Further analysis efforts revealed security weaknesses and novel schemes were designed afterwards. This paper provides a review of password-hashing schemes until the first quarter of 2017 and a relevant performance evaluation analysis on a common setting in terms of code size, memory consumption, and execution time.

VTBPEKE: Verifier-based Two-Basis Password Exponential Key Exchange

Abstract: PAKE protocols, for Password-Authenticated Key Exchange, enable two parties to establish a shared cryptographically strong key over an insecure network using a short common secret as authentication means. After the seminal work by Bellovin and Merritt, with the famous EKE, for Encrypted Key Exchange, various settings and security notions have been defined, and many protocols have been proposed. In this paper, we revisit the promising SPEKE, for Simple Password Exponential Key Exchange, proposed by Jablon. The only known security analysis works in the random oracle model under the CDH assumption, but in the multiplicative groups of finite fields only (subgroups of Zp*), which means the use of large elements and so huge communications and computations. Our new instantiation (TBPEKE, for Two-Basis Password Exponential Key Exchange) applies to any group, and our security analysis requires a DLIN-like assumption to hold. In particular, one can use elliptic curves, which leads to a better efficiency, at both the communication and computation levels. We additionally consider server corruptions, which immediately leak all the passwords to the adversary with symmetric PAKE. We thus study an asymmetric variant, also known as VPAKE, for Verifier-based Password Authenticated Key Exchange. We then propose a verifier-based variant of TBPEKE, the so-called VTBPEKE, which is also quite efficient, and resistant to server-compromise.

PASDJO: quantifying password strength perceptions with an online game

Abstract: Users often fail to create strong passwords. Besides lack of motivation, another possible explanation are misconceptions about the factors that contribute to password strength. Such misconceptions play an important role for the design of feedback systems during password selection. In this paper, we present an online game that helps quantifying the perception of password strength. Players score points by rating the strength of passwords accurately under time pressure. We analyzed the usage logs from the first four months after rollout. We found that users underestimate passphrases by 1.4 points on a 5-point strength scale, while their other ratings are fairly consistent with our estimates. Although we used a different methodology, we were able to corroborate related findings and narrow down the features that users think contribute to password strength. We highlight how the data collected through PASDJO can help designing better password feedback and boost user experience during account creation.

Do Differences in Password Policies Prevent Password Reuse

Abstract: Password policies were originally designed to make users pick stronger passwords. However, research has shown that they often fail to achieve this goal. In a systematic audit of the top 100 web sites in Germany, we explore if diversity in current real-world password policies prevents password reuse. We found that this is not the case: we are the first to show that a single password could hypothetically fulfill 99% of the policies under consideration. This is especially problematic because password reuse exposes users to similar risks as weak passwords. We thus propose a new approach for policies that focuses on password reuse and respects other websites to determine if a password should be accepted. This re-design takes current user behavior into account and potentially boosts the usability and security of password-based authentication.

An enhanced dynamic ID-based authentication scheme for telecare medical information systems

Abstract: The authentication schemes for telecare medical information systems (TMIS) try to ensure secure and authorized access. ID-based authentication schemes address secure communication, but privacy is not properly addressed. In recent times, dynamic ID-based remote user authentication schemes for TMIS have been presented to protect users privacy. The dynamic ID-based authentication schemes efficiently protect the users privacy. Unfortunately, most of the existing dynamic ID-based authentication schemes for TMIS ignore the input verifying condition. This makes login and password change phases inefficient. Inefficiency of the password change phase may lead to denial of service attack in the case of incorrect input in the password change phase. To overcome these weaknesses, we proposed a new dynamic ID-based authentication scheme using a smart card. The proposed scheme can quickly detect incorrect inputs which makes the login and password change phase efficient. We adopt the approach with the aim to protect privacy, and efficient login and password change phases. The proposed scheme also resists off-line password guessing attack and denial of service attack. We also demonstrate the validity of the proposed scheme by utilizing the widely-accepted BAN (Burrows, Abadi, and Needham) logic. In addition, our scheme is comparable in terms of the communication and computational overheads with relevant schemes for TMIS.

Lessons learned from evaluating eight password nudges in the wild

Abstract: Background. The tension between security and convenience, when creating passwords, is well established. It is a tension that often leads users to create poor passwords. For security designers, three mitigation strategies exist: issuing passwords, mandating minimum strength levels or encouraging better passwords. The first strategy prompts recording, the second reuse, but the third merits further investigation. It seemed promising to explore whether users could be subtly nudged towards stronger passwords. Aim. The aim of the study was to investigate the influence of visual nudges on self-chosen password length and/or strength. Method. A university application, enabling students to check course dates and review grades, was used to support two consecutive empirical studies over the course of two academic years. In total, 497 and 776 participants, respectively, were randomly assigned either to a control or an experimental group. Whereas the control group received no intervention, the experimental groups were presented with different visual nudges on the registration page of the web application whenever passwords were created. The experimental groups’ password strengths and lengths were then compared that of the control group. Results. No impact of the visual nudges could be detected, neither in terms of password strength nor length. The ordinal score metric used to calculate password strength led to a decrease in variance and test power, so that the inability to detect an effect size does not definitively indicate that such an effect does not exist. Conclusion. We cannot conclude that the nudges had no effect on password strength. It might well be that an actual effect was not detected due to the experimental design choices. Another possible explanation for our result is that password choice is influenced by the user’s task, cognitive budget, goals and pre-existing routines. A simple visual nudge might not have the power to overcome these forces. Our lessons learned therefore recommend the use of a richer password strength quantification measure, and the acknowledgement of the user’s context, in future studies.

Password typos resilience in honey encryption

Abstract: Honey encryption (HE) is a novel password-based encryption scheme which is secure against brute-force attack even if users' passwords have min-entropy. However, because decryption under a wrong key produces fake but valid-looking messages to everyone, typos in password may confuse even legitimate users in HE. This has been one of the most challenging problems in HE. In this paper, we propose two types of protocols that enable legitimate users to detect the typos in a password. We compare and analyze the performance and security of each scheme. The analysis results show that the proposed schemes can effectively solve the typos problem in HE while providing message recovery security.

Using Context-Based Password Strength Meter to Nudge Users' Password Generating Behavior: A Randomized Experiment

Abstract: Encouraging users to create stronger passwords has always been one of the key issues in password-based authentication. It is particularly important as passwords are still the most common user authentication method. Furthermore, prior works have highlighted that most passwords are significantly weak. In this paper, we seek to mitigate such an issue by proposing a context-based password strength meter and investigating its effectiveness on users' password generating behavior. We conduct a randomized experiment on Amazon MTurk involving hypothetical account creating scenarios. We observe the change in users' behavior in terms of the number of occasions where users change their password after seeing the warning message, the number of occasions where users want to learn more about creating stronger passwords, and the changes in password strength. We find that our proposed password strength meter is significantly effective. Users exposed to our password strength meter are more likely to change their password, and those new passwords are stronger. Furthermore, if the information is readily available, users are willing to invest their time to learn about creating a stronger password, even in a traditional password strength meter setting. Our findings suggest that simply incorporating a contextual information to password strength meters could be one of potential methods in promoting secure behaviors among end users.

A New Multimodal Approach for Password Strength Estimation—Part II: Experimental Evaluation

Abstract: A novel multimodal method for the estimation of password strength was presented in Part I of this series of two papers. In this paper, the experimental framework used for the evaluation of the novel approach is described. The method is evaluated following a reproducible protocol, which includes a three-dimensional approach: 1) deterministic assessment; 2) statistical assessment; and 3) third parties assessment (thanks to the availability upon request of an executable application that integrates the multimodal meter). The key experiment of the protocol compares, from a probabilistic point of view, the strength distributions assigned to passwords broken with increasingly complex attacking approaches, following a common strategy in a typical password cracking session. The experimental evaluation is carried out not only for the new meter, but also for other strength estimators from the state of the art, comparing their overall performance. In addition to its consistent results, the proposed method is highly flexible and can be adjusted to specific environments or to a certain password policy. Furthermore, it can also evolve over time in order to naturally adjust to new password selection trends followed by users.

Captcha as Graphical Passwords—a New Security Primitive Based On Hard Ai Problems

Abstract: Many security primitives are based on hard mathematical problems. Using hard AI problems for security is emerging as an exciting new paradigm, but has been underexplored. In this paper, we present a new security primitive based on hard AI problems, namely, a novel family of graphical password systems built on top of Captcha technology, which we call Captcha as graphical passwords (CaRP). CaRP is both a Captcha and a graphical password scheme. CaRP addresses a number of security problems altogether, such as online guessing attacks, relay attacks, and, if combined with dual-view technologies, shoulder-surfing attacks. Notably, a CaRP password can be found only probabilistically by automatic online guessing attacks even if the password is in the search set. CaRP also offers a novel approach to address the well-known image hotspot problem in popular graphical password systems, such as PassPoints, that often leads to weak password choices. CaRP is not a panacea, but it offers reasonable security and usability and appears to fit well with some practical applications for improving online security.

Graphical password: prevent shoulder-surfing attack using digraph substitution rules

Abstract: In this paper, a new scheme that uses digraph substitution rules to conceal the mechanism or activity required to derive password-images is proposed. In the proposed method, a user is only required to click on one of the pass-image instead of both pass-images shown in each challenge set for three consecutive sets.While this activity is simple enough to reduce login time, the images clicked appear to be random and can only be obtained with complete knowledge of the registered password along with the activity rules. Thus, it becomes impossible for shoulder-surfing attackers to obtain the information about which password images and pass-images are used by the user. Although the attackers may know about the digraph substitution rules used in the proposed method, the scenario information used in each challenge set remains. User study results reveal an average login process of less than half a minute. In addition, the proposed method is resistant to shoulder-surfing attacks.

An evaluation of the Game Changer Password System: A new approach to password security

Abstract: We propose – and experimentally test – a mnemonic variant of password security that uses game positions as passwords. In Experiment 1, we report accuracy and reaction time data when high school student, younger adult, and older adult participants remembered and entered one game-based password, using chess or Monopoly. In Experiment 2, we report accuracy and reaction time data from participants' use of five game-based passwords across 24 sessions over 10 weeks. All five passwords were stored in chess or Monopoly for the initial 20 sessions, and changed (from chess to Monopoly or vice versa) for the remaining sessions. This new approach to password security is both mathematically robust and user-friendly.