Entries Tagged "passwords"

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Scandinavian Attack Against Two-Factor Authentication

I’ve repeatedly said that two-factor authentication won’t stop phishing, because the attackers will simply modify their techniques to get around it. Here’s an example where that has happened:

Scandinavian bank Nordea was forced to shut down part of its Web banking service for 12 hours last week following a phishing attack that specifically targeted its paper-based one-time password security system.

According to press reports, the scam targeted customers that access the Nordea Sweden Web banking site using a paper-based single-use password security system.

A blog posting by Finnish security firm F-Secure says recipients of the spam e-mail were directed to bogus Web sites but were also asked to enter their account details along with the next password on their list of one-time passwords issued to them by the bank on a “scratch sheet”.

From F-Secure’s blog:

The fake mails were explaining that Nordea is introducing new security measures, which can be accessed at www.nordea-se.com or www.nordea-bank.net (fake sites hosted in South Korea).

The fake sites looked fairly real. They were asking the user for his personal number, access code and the next available scratch code. Regardless of what you entered, the site would complain about the scratch code and asked you to try the next one. In reality the bad boys were trying to collect several scratch codes for their own use.

The Register also has a story.

Two-factor authentication won’t stop identity theft, because identity theft is not an authentication problem. It’s a transaction-security problem. I’ve written about that already. Solutions need to address the transactions directly, and my guess is that they’ll be a combination of things. Some transactions will become more cumbersome. It will definitely be more cumbersome to get a new credit card. Back-end systems will be put in place to identify fraudulent transaction patterns. Look at credit card security; that’s where you’re going to find ideas for solutions to this problem.

Unfortunately, until financial institutions are liable for all the losses associated with identity theft, and not just their direct losses, we’re not going to see a lot of these solutions. I’ve written about this before as well.

We got them for credit cards because Congress mandated that the banks were liable for all but the first $50 of fraudulent transactions.

EDITED TO ADD: Here’s a related story. The Bank of New Zealand suspended Internet banking because of phishing concerns. Now there’s a company that is taking the threat seriously.

Posted on October 25, 2005 at 12:49 PMView Comments

Tamper-Evident Paper Mailings

We’ve all received them in the mail: envelopes from banks with PINs, access codes, or other secret information. The letters are somewhat tamper-proof, but mostly they’re designed to be tamper-evident: if someone opens the letter and reads the information, you’re going to know. The security devices include fully sealed packaging, and black inks that obscure the secret information if you hold the envelope up to the light.

Researchers from Cambridge University have been looking at the security inherent in these systems, and they’ve written a paper that outlines how to break them:

Abstract. Tamper-evident laser-printed PIN mailers are used by many institutions to issue PINs and other secrets to individuals in a secure manner. Such mailers are created by printing the PIN using a normal laser, but on to special stationery and using a special font. The background of the stationery disguises the PIN so that it cannot be read with the naked eye without tampering. We show that currently deployed PIN mailer technology (used by the major UK banks) is vulnerable to trivial attacks that reveal the PIN without tampering. We describe image processing attacks, where a colour difference between the toner and the stationary “masking pattern” is exploited. We also describe angled light attacks, where the reflective properties of the toner and stationery are exploited to allow the naked eye to separate the PIN from the backing pattern. All laser-printed mailers examined so far have been shown insecure.

According to a researcher website:

It should be noted that we sat on this report for about 9 months, and the various manufacturers all have new products which address to varying degrees the issues raised in the report.

BBC covered the story.

Posted on August 30, 2005 at 7:59 AMView Comments

The Kutztown 13

Thirteen Pennsylvania high-school kids — Kutztown 13 — are being charged with felonies:

They’re being called the Kutztown 13 — a group of high schoolers charged with felonies for bypassing security with school-issued laptops, downloading forbidden internet goodies and using monitoring software to spy on district administrators.

The students, their families and outraged supporters say authorities are overreacting, punishing the kids not for any heinous behavior — no malicious acts are alleged — but rather because they outsmarted the district’s technology workers….

The trouble began last fall after the district issued some 600 Apple iBook laptops to every student at the high school about 50 miles northwest of Philadelphia. The computers were loaded with a filtering program that limited Internet access. They also had software that let administrators see what students were viewing on their screens.

But those barriers proved easily surmountable: The administrative password that allowed students to reconfigure computers and obtain unrestricted Internet access was easy to obtain. A shortened version of the school’s street address, the password was taped to the backs of the computers.

The password got passed around and students began downloading such forbidden programs as the popular iChat instant-messaging tool.

At least one student viewed pornography. Some students also turned off the remote monitoring function and turned the tables on their elders_ using it to view administrators’ own computer screens.

There’s more to the story, though. Here’s some good commentary on the issue:

What the parents don’t mention — but the school did in a press release— is that it wasn’t as if the school came down with the Hammer of God out of nowhere.

These kids were caught and punished for doing this stuff, and their parents informed.

Over and over.

Quoth the release:

“Unfortunately, after repeated warnings and disciplinary actions, a few students continued to misuse the school-issued laptops to varying degrees. The disciplinary actions included detentions, in-school suspensions, loss of Internet access, and loss of computer privileges. After each disciplinary action, parents received either written notification or telephone calls.”

What was the parents’ reaction those disciplinary actions? Some of them complained that — despite signing a document agreeing to the acceptable use policy — the kids should be able to do whatever they wanted to with the free machines.

“We signed it, but we didn’t mean it”?

Yes, the kids should be punished. No, a felony comviction is not the way to punish them.

The problem is that the punishment doesn’t fit the crime. Breaking the rules is what kids do. Society needs to deal with that, yes, but it needs to deal with that in a way that doesn’t ruin lives. Deterrence is critical if we are to ever have a lawful society on the internet, but deterrence has to come from rational prosecution. This simply isn’t rational.

EDITED TO ADD (2 Sep): It seems that charges have been dropped.

Posted on August 22, 2005 at 6:56 AMView Comments

Hymn Project

The Hymn Project exists to break the iTunes mp4 copy-protection scheme, so you can hear the music you bought on any machine you want.

The purpose of the Hymn Project is to allow you to exercise your fair-use rights under copyright law. The various software provided on this web site allows you to free your iTunes Music Store purchases (protected AAC / .m4p) from their DRM restrictions with no loss of sound quality. These songs can then be played outside of the iTunes environment, even on operating systems not supported by iTunes and on hardware not supported by Apple.

Initially, the software recovered your iTunes password (your key, basically) from your hard drive. In response, Apple obfuscated the format and no one has yet figured out how to recover the keys cleanly. To get around this, they developed a program called FairKeys that impersonates iTunes and contacts the server. Since the iTunes client can still get your password, this works.

FairKeys … pretends to be a copy of iTunes running on an imaginary computer, one of the five computers that you’re currently allowed to authorize for playing your iTMS purchases. FairKeys logs into Apple’s web servers to get your keys the same way iTunes does when it needs to get new keys. At least for now, at this stage of the cat-and-mouse game, FairKeys knows how to request your keys and how to decode the response which contains your keys, and once it has those keys it can store them for immediate or future use by JHymn.

More security by inconvenience, and yet another illustration of the neverending arms race between attacker and defender.

Posted on July 11, 2005 at 8:09 AMView Comments

Security Skins

Much has been written about the insecurity of passwords. Aside from being guessable, people are regularly tricked into providing their passwords to rogue servers because they can’t distinguish spoofed windows and webpages from legitimate ones.

Here’s a clever scheme by Rachna Dhamija and Doug Tygar at the University of California Berkeley that tries to deal with the problem. It’s called “Dynamic Security Skins,” and it’s a pair of protocols that augment passwords.

First, the authors propose creating a trusted window in the browser dedicated to username and password entry. The user chooses a photographic image (or is assigned a random image), which is overlaid across the window and text entry boxes. If the window displays the user’s personal image, it is safe for the user to enter his password.

Second, to prove its identity, the server generates a unique abstract image for each user and each transaction. This image is used to create a “skin” that automatically customizes the browser window or the user interface elements in the content of a webpage. The user’s browser can independently reach the same image that it expects to receive from the server. To verify the server, the user only has to visually verify that the images match.

Not a perfect solution by any means — much Internet fraud bypasses authentication altogether — but two clever ideas that use visual cues to ensure security. You can also verify server authenticity by inspecting the SSL certificate, but no one does that. With this scheme, the user has to recognize only one image and remember one password, no matter how many servers he interacts with. In contrast, the recently announced Site Key (Bank of America’s implementation of the Passmark scheme) requires users to save a different image with each server.

Posted on July 1, 2005 at 7:31 AMView Comments

Write Down Your Password

Microsoft’s Jesper Johansson urged people to write down their passwords.

This is good advice, and I’ve been saying it for years.

Simply, people can no longer remember passwords good enough to reliably defend against dictionary attacks, and are much more secure if they choose a password too complicated to remember and then write it down. We’re all good at securing small pieces of paper. I recommend that people write their passwords down on a small piece of paper, and keep it with their other valuable small pieces of paper: in their wallet.

Posted on June 17, 2005 at 8:40 AMView Comments

Password Safe

Password Safe is a free Windows password-storage utility. These days, anyone who is on the Web regularly needs too many passwords, and it’s impossible to remember them all. I have long advocated writing them all down on a piece of paper and putting it in your wallet.

I designed Password Safe as another solution. It’s a small program that encrypts all of your passwords using one passphrase. The program is easy to use, and isn’t bogged down by lots of unnecessary features. Security through simplicity.

Password Safe 2.11 is now available.

Currently, Password Safe is an open source project at SourceForge, and is run by Rony Shapiro. Thank you to him and to all the other programmers who worked on the project.

Note that my Password Safe is not the same as this, this, this, or this PasswordSafe. (I should have picked a more obscure name for the program.)

It is the same as this, for the PocketPC.

Posted on June 15, 2005 at 1:35 PMView Comments

Phishing and Identity Theft

I’ve already written about identity theft, and have said that the real problem is fraudulent transactions. This essay says much the same thing:

So, say your bank uses a username and password to login to your account. Conventional wisdom (?) says that you need to prevent the bad guys from stealing your username and password, right? WRONG! What you are trying to prevent is the bad guys STEALING YOUR MONEY. This distinction is very important. If you have an account with $0 dollars in it, which you never use, what does it matter if someone knows the access details? Your username and password are only valuable insofar as the bank allows anyone who knows them to take your money. And therein lies the REAL problem. The bank is too lazy (or incompetent) to do what Bruce Schneier describes as “authenticate the transaction, not the person”. While it is incredibly difficult to prevent the bad guys from stealing access credentials (especially with browsers like Internet Explorer around), it is actually much simpler to prevent your money disappearing off to some foreign country….

When something goes wrong, the bank will tell you that you “authorised” the transaction, where in fact the party who ultimately “authorised” it is the bank, based on the information they chose to take as evidence that this transaction is the genuine desire of a legitimate customer.

The essay provides some recommendations as well.

  • Restrict IP addresses outside Australia
  • Restrict odd times of day (or at least be more vigilant)
  • Set cookies to identify machines
  • Record IP usually used
  • Record times of day usually accessed
  • Record days of week/month
  • Send emails when suspicious activity is detected
  • Lock accounts when fraud is suspected
  • Introduce a delay in transfers out — for suspicious amounts, longer
  • Make care proportional to risk
  • Define risk relative to customer, not bank

These are good ideas, but need more refinement in the specifics. But they’re a great start, and banks would do well to pay attention to them.

Posted on May 10, 2005 at 4:24 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.