BGP security was a hot topic a few years ago, but is not as much studied these years. However, with technologies such as IPv6 and DNSSEC, BGP security is making a comeback, especially in the industry. We academics also have much to contribute in this space. In today’s Three Paper Thursday, I will highlight three recent work related to BGP security. It is also a good starting point to catch up in BGP security for those whose last memories of BGP security involve proposals such as S-BGP and SoBGP.
Category: Security engineering
Bad security, good security, case studies, lessons learned
-
Some evidence on multi-word passphrases
Using a multi-word “passphrase” instead of a password has been suggested for decades as a way to thwart guessing attacks. The idea is now making a comeback, for example with the Fastwords proposal which identifies that mobile phones are optimised for entering dictionary words and not random character strings. Google’s recent password advice suggests condensing a sentence to form a password, while Komanduri et al.’s recent lab study suggests simply requiring longer passwords may be the best security policy. Even xkcd espouses multi-word passwords (albeit with randomly-chosen words). I’ve been advocating through my research though that authentication schemes can only be evaluated by studying large user-chosens distribution in the wild and not the theoretical space of choices. There’s no public data on how people choose passphrases, though Kuo et al.’s 2006 study for mnemonic-phrase passwords found many weak choices. In my recent paper (written with Ekaterina Shutova) presented at USEC last Friday (a workshop co-located with Financial Crypto), we study the problem using data crawled from the now-defunct Amazon PayPhrase system, introduced last year for US users only. Our goal wasn’t to evaluate the security of the scheme as deployed by Amazon, but learn more how people choose passphrases in general. While this is a relatively limited data source, our results suggest some caution on this approach. (more…)
-
Social authentication – harder than it looks!
This is the title of a paper we’ll be presenting next week at the Financial Crypto conference (slides). There is also coverage in the New Scientist.
Facebook has a social authentication mechanism where you may be asked to recognise some of your friends from photos as part of the login process. We analysed this and found it to be vulnerable to guessing by your friends, and also to modern face-recognition systems. Most people want privacy only from those close to them; if you’re having an affair then you want your partner to not find out but you don’t care if someone in Mongolia learns about it. And if your partner finds out and becomes your ex, then you don’t want them to be able to cause havoc on your account. Celebrities are similar, except that everyone is their friend (and potentially their enemy).
Second, if someone outside your circle of friends is doing a targeted attack on you, then by friending your friends they can get some access to your social circle to collect photos, which they might use in image-recognition software or even manually to pass the test.
(more…) -
How hard are PINs to guess?
Note: this research was also blogged today at the NY Times’ Bits technology blog.
I’ve personally been researching password statistics for a few years now (as well as personal knowledge questions) and our research group has a long history of research on banking security. In an upcoming paper at next weel’s Financial Cryptography conference written with Sören Preibusch and Ross Anderson, we’ve brought the two research threads together with the first-ever quantitative analysis of the difficulty of guessing 4-digit banking PINs. Somewhat amazingly given the importance of PINs and their entrenchment in infrastructure around the world, there’s never been an academic study of how people actually choose them. After modeling banking PIN selection using a combination of leaked data from non-banking sources and a massive online survey, we found that people are significantly more careful choosing PINs then online passwords, with a majority using an effectively random sequence of digits. Still, the persistence of a few weak choices and birthdates in particular suggests that guessing attacks may be worthwhile for an opportunistic thief. (more…)
-
Observations from two weeks of SSH brute force attacks
Earlier this month, I blogged about monitoring password-guessing attacks on a server, via a patched OpenSSH. This experiment has now been running for just over two weeks, and there are some interesting results. I’ve been tweeting these since the start.
As expected, the vast majority of password-guessing attempts are quite dull, and fall into one of two categories. Firstly there are attempts with a large number of ‘poor’ passwords (e.g. “password”, “1234”, etc…) against a small number of accounts which are very likely to exist (almost always “root”, but sometimes others such as “bin”).
Secondly, there were attempts on a large number of accounts which might plausibly exist (e.g. common first names and software packages such as ‘oracle’). For these, there were a very small number of password attempts, normally only trying the username as password. Well established good practices such as choosing a reasonably strong password and denying password-based log-in to the root account will be effective against both categories of attacks. Surprisingly, there were few attempts which were obviously default passwords from software packages (but they perhaps were hidden in the attempts where username equalled password). However, one attempt was username: “rfmngr”, password: “$rfmngr$”, which is the default password for Websense RiskFilter (see p.10 of the manual).
There were, however, some more interesting attempts. (more…)