RSS LinkedIn Google Plus

Call us: 0800 014 9884

Fun with passwords

Matthew Pettitt is an expert in computer security issues. He was recently placed in the top 12 of the UK Cyber Security Challenge entrants, having competed against 4000 others for this distinction.

Most people nowadays have dozens of accounts for different online sites and services. Every site you visit seems to demand another account, and for each account you need a password. Surely it can’t hurt to reuse a password?

Wrong!

For example, Andrew has accounts with his online banking service (userid ANDY897829), a popular microblogging service (@andrew), a small forum site for collectors of vintage coffee grinders (username CoffeeAndy), and an online bookstore (username Andrew). He’s also got an online email service, where he has the email address andrew@example.com.

He uses the same password for the microblogging service, the forum and the bookstore, but decides to pick a completely different password for his banking and email services.

Everything seems fine, until one day he visits the forum to find a message saying that the user database has been stolen (these were nice hackers – generally, sites don’t find out until their users start having problems), and that he should change his login password. It’s a bit inconvenient, but he changes his password, and thinks nothing more of the incident.

Until his next bank statement arrives, anyway. At that point, Andrew notices a number of orders from the online bookstore which he doesn’t remember making are listed on it.

What happened?

  1. The forum’s passwords weren’t encrypted, or, just as good, from the hackers point of view, were encrypted with reversible encryption
  2. The forum database contained his email address – this is fairly standard, and not a problem in itself, but meant that the hackers could do a search on the popular microblogging site for a user with that password, and link CoffeeAndy with @andrew
  3. They then logged into his microblogging account, using the password from the forum database – at this point, the attack would have been stopped if he’d used different passwords for each account
  4. At this point, they still don’t know about his bookshop or banking accounts, so they looked through his direct messages. At some point in the past, just before Christmas, Andrew had sent a link to his wishlist on the online bookstore to a friend: http://bookshop.example.com/wishlist/Andrew
  5. Now the hackers have his bookshop username. They log in, using the same password, and change the email address on the account, then start spending, using the “one click” purchase option – it asks for a password, but not for bank card details. They are careful only to order downloadable items – the one click option doesn’t let them change the delivery address – but that includes music, ebooks, downloadable films, software, gift vouchers…
  6. Once they’re done, they change the email address back, so Andrew never knows that they’ve been into his account, until his bank statement arrives

The important thing to note with this is that the bank login details are never compromised. There is no benefit to the hackers to attempt getting into the online banking system, most of which are multi-factor protected anyway (so you need a password, and some other code, either based on a “secret phrase”, or a code generator, which gives out codes based on the current time which are only valid for a short while).

It also doesn’t matter that the accounts have different usernames, as most people connect accounts, either consciously (“Find friends on these services! Just enter your username now!”) or through other means (such as posting links to your posts on a forum, posting the same status message to multiple services, sending links to one service using another).

The whole attack relied on a single password being used – it became the weak link in the chain. It didn’t help that the forum used bad password storage, but given unique passwords for each service, it wouldn’t have mattered.

How can you pick secure passwords?

  • Use a short phrase you can remember, possibly related to the site. Andrew could use “arabica_is_number_1″ for his coffee forum, “7_coffeetable_books” for his bookshop, “short_sweet_160″ for his microblog. By chaining multiple words together, the attack area for brute force attacks is increased massively, and because the phrases relate to the sites, are easier to remember than random strings.
  • Use a base password, and a way of adding site uniqueness to it that is secret. Andrew could use “c0ff33″ as his base password, then create “cf0ofrfu3m3″ by interleaving “forum” with it, “cb0ofofk3s3hop” by interleaving “bookshop” and “cm0ifcfr3o3blog” by interleaving “microblog”. It would be even better to have a more complex base password, or a different interleave pattern, such as interleaving backwards, or putting pairs of letters together. The idea is that you only have to remember one password and one method, which is a lot easier than remembering lots of fully unique passwords.
  • Use a password safe. Programs such as KeePass let you store passwords in a password protected file. You remember the password to the file, and can access all the other passwords, copy them to your clipboard, paste them into password fields, and never have to deal with them. They can also generate really complicated passwords (e.g. “TR%:,AJ?8a8-]S78h’*V”) which are virtually impossible to brute force. They have the downside that you can’t access your accounts if you don’t have your password file and the software, or if you forget the master password, but if you pick your password safe software carefully, you should be able to find a single password file format that works on all your computers and on your mobile phone: keep one file in sync, and you can work anywhere.
    It’s even safe to email this file, as long as the master password is kept secure, since it’s encrypted – KeePass uses the AES cipher, which is certified for use for “Top Secret” information in the USA, for example.
Written by Matthew Pettitt

Google settles online abuse case Monday 24th of November, 2014by Martin Lindley Google has reached settlement with a businessman who was the victim of a sustained act of internet trolling. The search engine may have linked to over 3,600 pages of malicious content.

More on this story »

Sony Pictures systems seized by hackers Tuesday 25th of November, 2014by Dan Moores Sony Pictures staff computer screens in US offices were reportedly taken over by the image of a menacing red skeleton and a message from a group that introduced itself as "#GOP".

More on this story »

YouTube video bloggers warned on ‘misleading’ content Wednesday 26th of November, 2014by Andy Williams The ASA has warned video bloggers to clearly label when they are paid to promote products, after a complaint from a journalist and subsequent investigations.

More on this story »
theEword - 8 hours ago

We’ve delivered over 20 free knowledge share events in 2014, we will round off our events calendar with our digital trends event at #Google

Reply Retweet Favourite
theEword - 1 day ago

Read more about what Google and theEword are getting up to in Manchester next week! http://t.co/HjF13a09zo

Reply Retweet Favourite
theEword - 1 day ago

We want you all to benefit from our event with Google! Tweet us your questions and get answers straight from Google themselves #AsktheEword

Reply Retweet Favourite
theEword - 2 days ago

We are passionate about knowledge share and can’t wait to share snippets straight from Google with you on Monday http://t.co/HjF13a09zo

Reply Retweet Favourite
theEword - 2 days ago

We're partnering with Google for an event looking at digital trends for 2015 next week. More info here: http://t.co/etwwXV1fwq

Reply Retweet Favourite

The final Light a Fire of 2014 Friday 21st of November, 2014by Dan Moores For the fifth and final Light a Fire of 2014, Liane Grimshaw joined Dan Nolan in the cosy Library room at the Great John Street Hotel, sharing career anecdotes and wise advice.

More on this story »

Digital trends for 2015 on the agenda at our Google Partner ... Wednesday 26th of November, 2014by Dan Moores The Google North event will discuss the digital trends that will shape 2015, giving valuable insight into the ways in which businesses will be able to maximise the online presence.

More on this story »

theEweekly Wrap: 28 Nov Friday 28th of November, 2014by Dan Moores This week: Twitter will scan for apps, Bing labels mobile-friendly sites, and Jennifer Aniston prank video goes viral.

More on this story »

Who loves theEword

Who loves theEword Who loves theEword