Two-factor (SMS) authentication now easier for businesses/families

For over a year now, FastMail has supported two-factor authentication via SMS and one-time passwords. As a quick reminder, the way this works is:

  1. A user creates a new login password via the Options –> Alternative Logins page
  2. For a “one-time” alternate password, the user is shown a screen of one-time passwords they have to print out. Then each time they want to login, they use one of the passwords off that list, and cross it out because it can’t be used again
  3. For an “sms” alternate password, the user logins in with that password, and then a one-time password is sent to the users phone (as configured on the Options –> Personalities screen for the default personality) that they can use to login

This is especially useful for people travelling and using Internet Cafes or kiosks that they don’t necessarily trust, and might be infected with keyboard logging trojans that steal passwords. With a one time or sms password, the password can only be used once and is thus useless if stolen.

Additionally for extra security, the alternate logins can be setup as “restricted logins”. When using a restricted login, no emails for files can be deleted, so even if somehow a hacker hijacks your session, they can’t delete or damage any email or files in your account.

While these feature are very useful from a security stand point, the one-time passwords requires some pre-planning to print out and carry around the one-time password list, and the SMS passwords require purchasing SMS credits in your account.

For businesses and families, we’ve now made the SMS passwords easier to use. Basically now only the business/family has to buy SMS credits, and then any user in the family/business can use those credits to have an SMS password sent to them. This feature has to be enabled for the business/family on the Manage –> Business/Family Preferences screen via the Allow SMS two-factor logins preference.

So the detailed steps to make this work are:

  1. An administrator of the business/family has to login, go to the Manage –> Business/Family Preferences screen and enable the Allow SMS two-factor logins checkbox. After doing this, a new Buy SMS Credits option will appear on the Business/Family screen and in the sidebar
  2. Then the administrator has to purchase SMS credits via the Manage –> Buys SMS Credits screen
  3. Each user that wants to use an SMS login then has to login to their own account and go to Options –> Personalities and set the Mobile number on their default personality, and then go to Options –> Alternative Logins and create an SMS Password which they can then use to login and trigger an SMS password to be sent to their phone
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Hotmail and Google docs being abused for spam

A user forwarded me a particular annoying bit of spam the other day that I realised is going to be quite hard to combat.

  1. The email was sent from a Hotmail account. Clearly the spammers have broken the Hotmail CAPTCHA process (again), and thus are signing up 10,000’s or more accounts to send their spam. The main issue is that it means there’s no easy “source IP” to test against RBLs for blocking or scoring purposes. Hotmail does add a “X-Originating-IP” header, but that’s non-standard and for the cases I’ve seen, the IPs are not on any known black lists.

    This actually seems quite an effective process for spammers. Using new spambot compromised machines to only send via reputable services like Hotmail, Yahoo, etc. Basically I believe most RBLs are built using systems that only check against the original incoming SMTP connection (either at the SMTP stage, or via some feedback process that later scans back through the Received headers). They generally don’t look at custom headers like "X-Originating-IP". So even if spam checking software does check that header, not much RBL building software will, so as long as the spammer can keep those IPs so they’re only used for sending via other "trusted" services, the IPs will probably stay off RBLs for a long time.

    Given the constant battle Hotmail, Yahoo, Gmail, etc have stopping mass signups, CAPTCHAs days seem numbered. Already in some cases, Google have started requiring SMS verification for new gmail accounts, I expect this trend to spread to other services and companies over time as the CAPTCHA systems employed to try and stop abuse appear to be less and less effective every day.

  2. The email contained a bunch of random text. Also not unusual, but it makes any content analysis basically impossible
  3. The email contained a link to a public Google Docs page. Again, clearly spammers have broken the Google CAPTCHA process to signup masses of Google Docs accounts and fill with their spam landing pages. Again this means that URIBLs are ineffective against these types of emails because they can’t go and block Google Docs domains.

The net result was that the emails in question contained very little information to block against. Some composite rules could be created (eg from a Hotmail account, with a Google Docs link in it), but they’re clearly far too broad and likely to result in many false positives.

At the moment, the main things we can do about this are:

  1. Report the emails as spam to providers like Spamcop and others. This should both end up reflecting badly on the services that are being abused, but should also encourage improvements to make sure they do look for X-Originating-IP headers and the like to help build IP RBLs
  2. Report the Google Docs pages as abuse. I’d hope Google have good internal systems to handle this, so that if a bunch of pages are reported as abuse, they can track down similar pages and disable them and the associated signups as well
Posted in Technical. Comments Off on Hotmail and Google docs being abused for spam

Thunderbird 3 beta 3 includes native IMAP COMPRESS support

A few months back, we blogged about a new compression proxy we had developed that helped improve IMAP performance. If you’re using an email client to access FastMail via IMAP, then the compression proxy can significantly speed up access to your account, especially if you have large folders with lots of messages (I use it, and see > 80% bandwidth savings on average)

However if you’re a bleeding edge email user, and are trying out the Thunderbird beta releases, then definitely download the latest Thunderbird 3 beta 3 as it now includes native support for the COMPRESS extension. This means you don’t need to use the proxy at all, you can just setup Thunderbird to access our server as normal (server name = and it’ll automatically use the compressed protocol.

We don’t recommend using Thunderbird 3 yet if you’re a regular email user. It’s still definitely a beta, and has many known bugs. But if you like trying out new software and are aware of the potential caveats, then definitely give it a go!

Posted in Technical. Comments Off on Thunderbird 3 beta 3 includes native IMAP COMPRESS support

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