Entries Tagged "passwords"

Page 19 of 29

Password Advice

Here’s some complicated advice on securing passwords that—I’ll bet—no one follows.

  • DO use a password manager such as those reviewed by Scott Dunn in his Sept. 18, 2008,
    Insider Tips
    column. Although Scott focused on free programs, I really like CallPod’s Keeper, a $15 utility that comes in Windows, Mac, and iPhone versions and allows you to keep all your passwords in sync. Find more information about the program and a download link for the 15-day free-trial version on the vendor’s site.

  • DO change passwords frequently. I change mine every six months or whenever I sign in to a site I haven’t visited in long time. Don’t reuse old passwords. Password managers can assign expiration dates to your passwords and remind you when the passwords are about to expire.
  • DO keep your passwords secret. Putting them into a file on your computer, e-mailing them to others, or writing them on a piece of paper in your desk is tantamount to giving them away. If you must allow someone else access to an account, create a temporary password just for them and then change it back immediately afterward.

    No matter how much you may trust your friends or colleagues, you can’t trust their computers. If they need ongoing access, consider creating a separate account with limited privileges for them to use.

  • DON’T use passwords comprised of dictionary words, birthdays, family and pet names, addresses, or any other personal information. Don’t use repeat characters such as 111 or sequences like abc, qwerty, or 123 in any part of your password.
  • DON’T use the same password for different sites. Otherwise, someone who culls your Facebook or Twitter password in a phishing exploit could, for example, access your bank account.
  • DON’T allow your computer to automatically sign in on boot-up and thus use any automatic e-mail, chat, or browser sign-ins. Avoid using the same Windows sign-in password on two different computers.

  • DON’T use the “remember me” or automatic sign-in option available on many Web sites. Keep sign-ins under the control of your password manager instead.

  • DON’T enter passwords on a computer you don’t control—such as a friend’s computer—because you don’t know what spyware or keyloggers might be on that machine.

  • DON’T access password-protected accounts over open Wi-Fi networks—or any other network you don’t trust—unless the site is secured via https. Use a VPN if you travel a lot. (See Ian “Gizmo” Richards’ Dec. 11, 2008, Best Software column, “Connect safely over open Wi-Fi networks,” for Wi-Fi security tips.)
  • DON’T enter a password or even your account name in any Web page you access via an e-mail link. These are most likely phishing scams. Instead, enter the normal URL for that site directly into your browser, and proceed to the page in question from there.

I regularly break seven of those rules. How about you? (Here’s my advice on choosing secure passwords.)

Posted on August 10, 2009 at 6:57 AM • View Comments

Strong Web Passwords

Interesting paper from HotSec ’07: “Do Strong Web Passwords Accomplish Anything?” by Dinei Florêncio, Cormac Herley, and Baris Coskun.

ABSTRACT: We find that traditional password advice given to users is somewhat dated. Strong passwords do nothing to protect online users from password stealing attacks such as phishing and keylogging, and yet they place considerable burden on users. Passwords that are too weak of course invite brute-force attacks. However, we find that relatively weak passwords, about 20 bits or so, are sufficient to make brute-force attacks on a single account unrealistic so long as a “three strikes” type rule is in place. Above that minimum it appears that increasing password strength does little to address any real threat If a larger credential space is needed it appears better to increase the strength of the user ID’s rather than the passwords. For large institutions this is just as effective in deterring bulk guessing attacks and is a great deal better for users. For small institutions there appears little reason to require strong passwords for online accounts.

Posted on July 13, 2009 at 5:38 AM • View Comments

The Pros and Cons of Password Masking

Usability guru Jakob Nielsen opened up a can of worms when he made the case for unmasking passwords in his blog. I chimed in that I agreed. Almost 165 comments on my blog (and several articles, essays, and many other blog posts) later, the consensus is that we were wrong.

I was certainly too glib. Like any security countermeasure, password masking has value. But like any countermeasure, password masking is not a panacea. And the costs of password masking need to be balanced with the benefits.

The cost is accuracy. When users don’t get visual feedback from what they’re typing, they’re more prone to make mistakes. This is especially true with character strings that have non-standard characters and capitalization. This has several ancillary costs:

  • Users get pissed off.
  • Users are more likely to choose easy-to-type passwords, reducing both mistakes and security. Removing password masking will make people more comfortable with complicated passwords: they’ll become easier to memorize and easier to use.

The benefits of password masking are more obvious:

  • Security from shoulder surfing. If people can’t look over your shoulder and see what you’re typing, they’re much less likely to be able to steal your password. Yes, they can look at your fingers instead, but that’s much harder than looking at the screen. Surveillance cameras are also an issue: it’s easier to watch someone’s fingers on recorded video, but reading a cleartext password off a screen is trivial.

    In some situations, there is a trust dynamic involved. Do you type your password while your boss is standing over your shoulder watching? How about your spouse or partner? Your parent or child? Your teacher or students? At ATMs, there’s a social convention of standing away from someone using the machine, but that convention doesn’t apply to computers. You might not trust the person standing next to you enough to let him see your password, but don’t feel comfortable telling him to look away. Password masking solves that social awkwardness.

  • Security from screen scraping malware. This is less of an issue; keyboard loggers are more common and unaffected by password masking. And if you have that kind of malware on your computer, you’ve got all sorts of problems.
  • A security “signal.” Password masking alerts users, and I’m thinking users who aren’t particularly security savvy, that passwords are a secret.

I believe that shoulder surfing isn’t nearly the problem it’s made out to be. One, lots of people use their computers in private, with no one looking over their shoulders. Two, personal handheld devices are used very close to the body, making shoulder surfing all that much harder. Three, it’s hard to quickly and accurately memorize a random non-alphanumeric string that flashes on the screen for a second or so.

This is not to say that shoulder surfing isn’t a threat. It is. And, as many readers pointed out, password masking is one of the reasons it isn’t more of a threat. And the threat is greater for those who are not fluent computer users: slow typists and people who are likely to choose bad passwords. But I believe that the risks are overstated.

Password masking is definitely important on public terminals with short PINs. (I’m thinking of ATMs.) The value of the PIN is large, shoulder surfing is more common, and a four-digit PIN is easy to remember in any case.

And lastly, this problem largely disappears on the Internet on your personal computer. Most browsers include the ability to save and then automatically populate password fields, making the usability problem go away at the expense of another security problem (the security of the password becomes the security of the computer). There’s a Firefox plugin that gets rid of password masking. And programs like my own Password Safe allow passwords to be cut and pasted into applications, also eliminating the usability problem.

One approach is to make it a configurable option. High-risk banking applications could turn password masking on by default; other applications could turn it off by default. Browsers in public locations could turn it on by default. I like this, but it complicates the user interface.

A reader mentioned BlackBerry’s solution, which is to display each character briefly before masking it; that seems like an excellent compromise.

I, for one, would like the option. I cannot type complicated WEP keys into Windows—twice! what’s the deal with that?—without making mistakes. I cannot type my rarely used and very complicated PGP keys without making a mistake unless I turn off password masking. That’s what I was reacting to when I said “I agree.”

So was I wrong? Maybe. Okay, probably. Password masking definitely improves security; many readers pointed out that they regularly use their computer in crowded environments, and rely on password masking to protect their passwords. On the other hand, password masking reduces accuracy and makes it less likely that users will choose secure and hard-to-remember passwords, I will concede that the password masking trade-off is more beneficial than I thought in my snap reaction, but also that the answer is not nearly as obvious as we have historically assumed.

Posted on July 3, 2009 at 1:42 PM • View Comments

The Problem with Password Masking

I agree with this:

It’s time to show most passwords in clear text as users type them. Providing feedback and visualizing the system’s status have always been among the most basic usability principles. Showing undifferentiated bullets while users enter complex codes definitely fails to comply.

Most websites (and many other applications) mask passwords as users type them, and thereby theoretically prevent miscreants from looking over users’ shoulders. Of course, a truly skilled criminal can simply look at the keyboard and note which keys are being pressed. So, password masking doesn’t even protect fully against snoopers.

More importantly, there’s usually nobody looking over your shoulder when you log in to a website. It’s just you, sitting all alone in your office, suffering reduced usability to protect against a non-issue.

Shoulder surfing isn’t very common, and cleartext passwords greatly reduces errors. It has long annoyed me when I can’t see what I type: in Windows logins, in PGP, and so on.

EDITED TO ADD (6/26): To be clear, I’m not talking about PIN masking on public terminals like ATMs. I’m talking about password masking on personal computers.

EDITED TO ADD (6/30): Two articles on the subject.

Posted on June 26, 2009 at 6:17 AM • View Comments

Second SHB Workshop Liveblogging (6)

The first session of the morning was “Foundations,” which is kind of a catch-all for a variety of things that didn’t really fit anywhere else. Rachel Greenstadt moderated.

Terence Taylor, International Council for the Live Sciences (suggested video to watch: Darwinian Security; Natural Security), talked about the lessons evolution teaches about living with risk. Successful species didn’t survive by eliminating the risks of their environment, they survived by adaptation. Adaptation isn’t always what you think. For example, you could view the collapse of the Soviet Union as a failure to adapt, but you could also view it as successful adaptation. Risk is good. Risk is essential for the survival of a society, because risk-takers are the drivers of change. In the discussion phase, John Mueller pointed out a key difference between human and biological systems: humans tend to respond dramatically to anomalous events (the anthrax attacks), while biological systems respond to sustained change. And David Livingstone Smith asked about the difference between biological adaptation that affects the reproductive success of an organism’s genes, even at the expense of the organism, with security adaptation. (I recommend the book he edited: Natural Security: A Darwinian Approach to a Dangerous World.)

Andrew Odlyzko, University of Minnesota (suggested reading: Network Neutrality, Search Neutrality, and the Never-Ending Conflict between Efficiency and Fairness in Markets, Economics, Psychology, and Sociology of Security), discussed human-space vs. cyberspace. People cannot build secure systems—we know that—but people also cannot live with secure systems. We require a certain amount of flexibility in our systems. And finally, people don’t need secure systems. We survive with an astounding amount of insecurity in our world. The problem with cyberspace is that it was originally conceived as separate from the physical world, and that it could correct for the inadequacies of the physical world. Really, the two are intertwined, and that human space more often corrects for the inadequacies of cyberspace. Lessons: build messy systems, not clean ones; create a web of ties to other systems; create permanent records.

danah boyd, Microsoft Research (suggested reading: Taken Out of Context—American Teen Sociality in Networked Publics), does ethnographic studies of teens in cyberspace. Teens tend not to lie to their friends in cyberspace, but they lie to the system. Since an early age, they’ve been taught that they need to lie online to be safe. Teens regularly share their passwords: with their parents when forced, or with their best friend or significant other. This is a way of demonstrating trust. It’s part of the social protocol for this generation. In general, teens don’t use social media in the same way as adults do. And when they grow up, they won’t use social media in the same way as today’s adults do. Teens view privacy in terms of control, and take their cues about privacy from celebrities and how they use social media. And their sense of privacy is much more nuanced and complicated. In the discussion phase, danah wasn’t sure whether the younger generation would be more or less susceptible to Internet scams than the rest of us—they’re not nearly as technically savvy as we might think they are. “The only thing that saves teenagers is fear of their parents”; they try to lock them out, and lock others out in the process. Socio-economic status matters a lot, in ways that she is still trying to figure out. There are three different types of social networks: personal networks, articulated networks, and behavioral networks, and they’re different.

Mark Levine, Lancaster University (suggested reading: The Kindness of Crowds; Intra-group Regulation of Violence: Bystanders and the (De)-escalation of Violence), does social psychology. He argued against the common belief that groups are bad (mob violence, mass hysteria, peer group pressure). He collected data from UK CCTV cameras, searches for aggressive behavior, and studies when and how bystanders either help escalate or de-escalate the situations. Results: as groups get bigger, there is no increase of anti-social acts and a significant increase in pro-social acts. He has much more analysis and results, too complicated to summarize here. One key finding: when a third party intervenes in an aggressive interaction, it is much more likely to de-escalate. Basically, groups can act against violence. “When it comes to violence (and security), group processes are part of the solution—not part of the problem?”

Jeff MacKie-Mason, University of Michigan (suggested reading: Humans are smart devices, but not programmable; Security when people matter; A Social Mechanism for Supporting Home Computer Security), is an economist: “Security problems are incentive problems.” He discussed motivation, and how to design systems to take motivation into account. Humans are smart devices; they can’t be programmed, but they can be influenced through the sciences of motivational behavior: microeconomics, game theory, social psychology, psychodynamics, and personality psychology. He gave a couple of general examples of how these theories can inform security system design.

Joe Bonneau, Cambridge University, talked about social networks like Facebook, and privacy. People misunderstand why privacy and security is important in social networking sites like Facebook. People underestimate of what Facebook really is; it really is a reimplementation of the entire Internet. “Everything on the Internet is becoming social,” and that makes security different. Phishing is different, 419-style scams are different. Social context makes some scams easier; social networks are fun, noisy, and unpredictable. “People use social networking systems with their brain turned off.” But social context can be used to spot frauds and anomalies, and can be used to establish trust.

Three more sessions to go. (I am enjoying liveblogging the event. It’s helping me focus and pay closer attention.)

Adam Shostack’s liveblogging is here. Ross Anderson’s liveblogging is in his blog post’s comments. Matt Blaze’s audio is here.

Posted on June 12, 2009 at 9:54 AM • View Comments

Secret Questions

In 2004, I wrote about the prevalence of secret questions as backup passwords. The problem is that the answers to these “secret questions” are often much easier to guess than random passwords. Mother’s maiden name isn’t very secret. Name of first pet, name of favorite teacher: there are some common names. Favorite color: I could probably guess that in no more than five attempts.

The result is that the normal security protocol (passwords) falls back to a much less secure protocol (secret questions). And the security of the entire system suffers.

Here’s some actual research on the issue:

It’s no secret: Measuring the security and reliability of authentication via ‘secret’ questions

Abstract:

All four of the most popular webmail providers—AOL, Google, Microsoft, and Yahoo!—rely on personal questions as the secondary authentication secrets used to reset account passwords. The security of these questions has received limited formal scrutiny, almost all of which predates webmail. We ran a user study to measure the reliability and security of the questions used by all four webmail providers. We asked participants to answer these questions and then asked their acquaintances to guess their answers. Acquaintance with whom participants reported being unwilling to share their webmail passwords were able to guess 17% of their answers. Participants forgot 20% of their own answers within six months. What’s more, 13% of answers could be guessed within five attempts by guessing the most popular answers of other participants, though this weakness is partially attributable to the geographic homogeneity of our participant pool.

Posted on May 25, 2009 at 9:56 AM • View Comments

Researchers Hijack a Botnet

A bunch of researchers at the University of California Santa Barbara took control of a botnet for ten days, and learned a lot about how botnets work:

The botnet in question is controlled by Torpig (also known as Sinowal), a malware program that aims to gather personal and financial information from Windows users. The researchers gained control of the Torpig botnet by exploiting a weakness in the way the bots try to locate their commands and control servers—the bots would generate a list of domains that they planned to contact next, but not all of those domains were registered yet. The researchers then registered the domains that the bots would resolve, and then set up servers where the bots could connect to find their commands. This method lasted for a full ten days before the botnet’s controllers updated the system and cut the observation short.

During that time, however, UCSB’s researchers were able to gather massive amounts of information on how the botnet functions as well as what kind of information it’s gathering. Almost 300,000 unique login credentials were gathered over the time the researchers controlled the botnet, including 56,000 passwords gathered in a single hour using “simple replacement rules” and a password cracker. They found that 28 percent of victims reused their credentials for accessing 368,501 websites, making it an easy task for scammers to gather further personal information. The researchers noted that they were able to read through hundreds of e-mail, forum, and chat messages gathered by Torpig that “often contain detailed (and private) descriptions of the lives of their authors.”

Here’s the paper:

Abstract:

Botnets, networks of malware-infected machines that are controlled by an adversary, are the root cause of a large number of security threats on the Internet. A particularly sophisticated and insidious type of bot is Torpig, a malware program that is designed to harvest sensitive information (such as bank account and credit card data) from its victims. In this paper, we report on our efforts to take control of the Torpig botnet for ten days. Over this period, we observed more than 180 thousand infections and recorded more than 70 GB of data that the bots collected. While botnets have been “hijacked” before, the Torpig botnet exhibits certain properties that make the analysis of the data particularly interesting. First, it is possible (with reasonable accuracy) to identify unique bot infections and relate that number to the more than 1.2 million IP addresses that contacted our command and control server. This shows that botnet estimates that are based on IP addresses are likely to report inflated numbers. Second, the Torpig botnet is large, targets a variety of applications, and gathers a rich and diverse set of information from the infected victims. This opens the possibility to perform interesting data analysis that goes well beyond simply counting the number of stolen credit cards.

Another article.

Posted on May 11, 2009 at 6:56 AM • View Comments

1 … 17 18 19 20 21 … 29

Sidebar photo of Bruce Schneier by Joe MacInnis.