While this is true for many passwords, it’s extremely insecure to use just one or two words from the dictionary as a password. Traditionally, security researchers make an assumption that most passwords are based on dictionary words. Reducing the number of possible combinations to try during the attack is the most efficient and cost-effective way of breaking passwords. There are two ways to speed up the attack: increasing attack speed or reducing the number of passwords to try. Of course, you can speed it up by adding more GPU accelerators and building a network for performing a distributed attack, but there are smarter attacks that are much cheaper and a lot faster than brute-force. In other words, you’re looking at the following real-world recovery speeds: A more typical 8-character alphanumeric password has 2.8 trillion possible combinations will take 12.5 years to break. With a computer equipped with a GTX 1080 board that is capable of trying 7100 passwords per second (Microsoft Office 2013) you’re looking 12 hours of brute-forcing, which is quite reasonable. For example, a very simple password containing 6 lower-case letters and no numbers already has 309 million possible combinations. Using an online password calculator, we can count how many possible combinations there are for the different types of passwords. Granted, you can bump up the number of GTX boards or use several computers, and while it does help, it may still not be fast enough. We came to that number on a single high-end PC equipped with a single NVIDIA GTX 1080 board. Even the latest hardware can offer just barely acceptable speeds when attacking modern protection formats such as Microsoft BitLocker or Office 2013 passwords.Īs you can see, attacking an Office 2013 document is relatively slow at only 7100 passwords per second. So why are we saying that brute-force attacks are inefficient? It’s simply a matter of speed. With today’s GPU acceleration algorithms, cloud computing and distributed attacks, one can gather substantial resources to crack a password. The second method will be described in the follow-up article. In this article, we’ll discuss the first of the two relatively unknown vectors of attack that can potentially break 30 to 70 per cent of real-world passwords in a matter of minutes. encrypted Office 2013 documents), while using general dictionaries can still be too much for speedy attacks and too little to actually work. Brute-force attacks are inefficient for modern formats (e.g. It’s no secret that simply getting a good password recovery tool is not enough to successfully break a given password. ![]() Session IDs should not be in the URL, be securely stored and invalidated after logout, idle, and absolute timeouts.This article opens a new series dedicated to breaking passwords. * Use a server-side, secure, built-in session manager that generates a new random session ID with high entropy after login. Log all failures and alert administrators when credential stuffing, brute force, or other attacks are detected. * Limit or increasingly delay failed login attempts. * Ensure registration, credential recovery, and API pathways are hardened against account enumeration attacks by using the same messages for all outcomes. * Align password length, complexity and rotation policies with NIST 800-63 B’s guidelines in section 5.1.1 for Memorized Secrets or other modern, evidence based password policies. * Implement weak-password checks, such as testing new or changed passwords against a list of the top 10000 worst passwords. * Do not ship or deploy with any default credentials, particularly for admin users. * Where possible, implement multi-factor authentication to prevent automated, credential stuffing, brute force, and stolen credential re-use attacks. User sessions or authentication tokens (particularly single sign-on (SSO) tokens) aren’t properly invalidated during logout or a period of inactivity. * Does not properly invalidate Session IDs. * Does not rotate Session IDs after successful login. * Exposes Session IDs in the URL (e.g., URL rewriting). * Has missing or ineffective multi-factor authentication. * Uses plain text, encrypted, or weakly hashed passwords (see A3:2017-Sensitive Data Exposure). * Uses weak or ineffective credential recovery and forgot-password processes, such as “knowledge-based answers”, which cannot be made safe. * Permits default, weak, or well-known passwords, such as “Password1” or “admin/admin“. * Permits brute force or other automated attacks. * Permits automated attacks such as credential stuffing, where the attacker has a list of valid usernames and passwords. ![]() There may be authentication weaknesses if the application: Confirmation of the user’s identity, authentication, and session management are critical to protect against authentication-related attacks.
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