Archive for the ‘Security’ Category

Mobile broadband

Saturday, August 22nd, 2009

Mobile broadband is the mobile phone networks’ current favourite product.  For them it’s incremental revenue with little or no infrastructure revenue. 

We’ve recently started looking at mobile broadband for business use, but it’s worth starting with a summary of why we’re so late to the party:

  • our network support team doesn’t get many calls about it
  • mobile broadband speeds are highly variable, and generally far less than the advertised top speed
  • mobile broadband support is usually installed directly from the “usb modem”, and there is a risk of it tussling with existing network support for, especially, wifi networks
  • for light use business mobile phones can often also be used for mobile broadband (though there there be terms of use restrictions which formally prohibit this)

The obvious business uses for mobile broadband are:

  • Email, particularly if you want to work with email attachments while out and about
  • Web, though arguably the current generation of smartphones are easier and quicker to use in most instance
  • Remote access to business systems

We plan to write about email later.  The gist though is that it is simple, but there are some security risks to consider.

Remote access to business systems needs to be secure, and this is generally achieved through a “vpn”. 

The details don’t really matter, but we tested with:

  • Orange mobile broadband
  • Huawei E160E usb modem
  • Cisco software vpn
  • security implemented so that the user has to provide their network username and password in order to gain access
  • Microsoft Terminal Server client

The mobile broadband connected using a 3G service.  This is the middle of the three types of service (GPRS/Edge; 3G, HSDPA) that are available.  The test was done on a Saturday, with one eye on England stepping on the Aussies. 

Perhaps as a reward for working Saturday the speed of the connection was roughly twice that during the working week.  Still nothing to cheer about though, at about 10% of the advertised maximum speed.

Connection was easy and quick, no different from connecting by landline broadband.  The good news is that the speed was ok, not great, but certainly good enough for emergency or light use. 

Although the connection was ok, if you plan regular or heavy use, then our experience suggests that you need to consider providing a web interface to your business systems.  Which is a whole other story.

There doesn’t seem to be much web based comment on mobile broadband for business use.  Colin DiPonio works in university IT and found that vpns were similarly easy to get working.  His experience is with Linux rather than Windows computers though.  It has to be said that this is an occasion where I’d happily trade the openness of Linux support (provided via NetworkManager and ConnMan) for the Windows experience of software being thrown willy nilly at our carefully maintained computers by the usb modems.

Barebones leaving process

Saturday, July 18th, 2009

While most businesses have a collection of processes covering their IT infrastructure, one area that is often neglected is when staff leave.  Its highly likely that most companies will have user accounts still active for staff that have left some time ago.  This not only leads to administrative problems but can also be a security risk.

The most obvious course of action when a staff member leaves is to simply delete their account.  While this is a quick process, and immediately gets around the security issues, it can often cause other problems.  There are a number of things which should be considered when putting together a leaving process:

Is the user’s email data going to be needed going forward?  Experience from our IT helpdesk tells us that you can guarantee that just after the account is deleted, a manager will ask you to check for something!

  • Does email still need to be received at the user’s address?
  • Is the user’s profile stored on a server and does it need to be kept?
  • Does the user’s profile or data need to be accessible on their old PC?

Bearing these points in mind, the following is a recommended process for when staff leave:-

  1. Log in to their account and export they email to a PST file.  Copy this PST to a leavers’ area on a data drive, along with any other PSTs they may have.  If other staff need access to their email, they can be given a copy of this PST.
  2.  If they have a server based profile, move their profile to the leavers’ area and delete their local copy on their PC (this avoids whoever uses their PC afterwards potentially having access to data they shouldn’t).
  3. If they just have a local profile, copy this to the leavers’ area and then delete it from their PC.
  4. If they have a personal network drive, copy this to the leavers’ area and then delete.
  5. Amend their primary SMTP email address to be something generic (such as adding a zz at the start).  Their previous  address can then be assigned to another user if mail still needs to be received.
  6. Disable their Active Directory account, which also disables their mailbox and hides them from the GAL.
  7. After a period of time, such as 30 days, their account should be deleted (this covers them possibly changing their mind and coming back!).
  8. Periodically, the leavers’ area on the server can be archived to tape  or DVD to recover disk space. 

This process will ensure that leavers’ accounts are dealt with correctly but their user data is still available should it be required.

Password blues

Wednesday, June 10th, 2009

For the average computer user, password management often involves either their pet’s name or a selection of Post-It notes on their monitor.  While for some this may be the only way to remember their passwords, there are a number of guidelines that can be followed to ensure users create strong, secure passwords that are also easy to remember without having to write them down.

It’s a popularly held belief that the best passwords are those made up of random strings of upper and lower case letters, numbers, and other symbols.  While these are indeed the most difficult to crack via a brute force attack and tend to be impervious to dictionary attacks, they are also the most difficult to remember and therefore the most likely to be written done.  The most complex password becomes useless when its easily accessible by other people.

The complexity of a password increases exponentially as the password’s length increases.  There are over 10,000 more password combinations for a 15 character password using just lower case letters than there are for an 8 character password using upper and lower case letters, numbers, and all the symbols easily accessible on a normal keyboard.  Therefore, you don’t need to use every character available just to get a complex password.

Many people also don’t realise that Windows passwords can be up to 127 characters long and can also contain a space.  This makes it very easy to construct a complex password, which is in essence a pass phrase, which is easy to remember.  A good way to start is to take a simple phrase, such as “summer is” here and apply some standard rules to it.  For example, you could capitalise the second letter or each word, rather than the first, to make it more difficult to guess.  You could then add a specific symbol at the end of the password.  Lastly, you could substitute specific letters for symbols or numbers (such as “@” for “a” and “5″ for “s”).  This makes the password “5Ummer i5 hEre!” which is very complex and well protected from common password attacks.  If you keep the same set of standard rules, it’s also easy to remember.  Additionally, if you need to write anything down, you can write down the rules rather than the password itself which is a much lower risk.

When you need to change your password, you simply need to select a new phrase and apply the same rules – “now its autumn” would then become “nOw iT5 @Utumn!”, another complex yet easy to remember password.

One last point – there is always going to be a need at some point to write down a password.  Some passwords, such as the Windows Directory Services Restore Mode password, are designed to never be used except in an emergency.  These are therefore going to need to be recorded somewhere to ensure access when needed.  Writing these passwords down is not in itself a security risk – it’s what you do after they are written down that can cause the problem.  Locking the password is a safe with controlled access should present very little risk at all, and as the use of these passwords is very limited, it shouldn’t be a problem if accessing them takes time.