Un-shortening URLs

URL shortening services such as bit.ly are very popular, but sometimes they can be dangerous. This is why I am glad to see that a url un-shortening service http://www.websiteplanet.com/webtools/redirected/ is now available.

The way url shorteners work is that I can set up http://bit.ly/2Ffns9i as a short url for http://brianodonovan.ie and then you can save yourself some typing by typing http://bit.ly/2Ffns9i into your address bar and be brought directly to http://brianodonovan.ie . In this case the number of keystrokes is hardly worth the effort, but in many cases URLs can be very long and hence difficult to type in correctly.

The danger of short URLs is that you don't know where they are going to bring you to. For example you might be expecting to be brought to https://www.mybank.com/myaccount but instead find yourself brought to http://www.hackers.ru/defraud-me

The way http://www.websiteplanet.com/webtools/redirected/ works is that you go there and type in your short URL and it tells you where you will be redirected to if you use that short URL (this might involve multiple redirects). You can then decide whether or not you feel safe to visit the site in question.

Security for stand-alone Java programs that use the Notes API

Since its launch in the early 1990s, Lotus Notes has had a wonderful security architecture which implemented a public/private key architecture which has only recently been widely adopted by other platforms. Unfortunately this meant that many people are not really familiar with how it works.

I recently blogged about how to write stand-alone Java programs which can manipulate Notes/Domino databases. A few people commented upon the fact that when they run their stand-alone programs on a machine on which they have a Notes client installed they are normally prompted to enter a password each time the program launches. Since they don't get a similar password prompt when they run their program on a machine which has a Domino server installed on it, they seem tro think that the Domino server code gives them some form of privelege to bypass Notes security. This is not true, but to explain why I will first need to explain some important facts about Notes/Domino secuirty model.

1. Notes implements what security experts call "two factor authentication". This means that you need to prove your identity by two different mechanisms. Firstly you need to have an ID file containing your private key and secondly you need to know the password used to secure the ID file.
2. Domino servers also have ID files to prove their identity. However, most administrators insist that their real human users choose a complex password to secure their ID file and change it frequently, but most administrators don't use any password at all on their servers' ID files. This is because otherwise they would need a human to be present to type in the password every time the server is restarted and in any case sharing the ID file's password with all of the potential administrators would negate any security benefit from having a password.

When you run a Java stand-alone program that used the Notes API on a machine which has the Notes client installed you will run with the identity of currently installed ID file (which typically requires you to type a password). When you run this same program on a machine which has the Domino server installed you will run with the identity of server's ID file (which probably doesn't require you to type a password). Because of this you will need to ensure that the server is granted the appropriate access rights to the databases your program needs to use.

Domino has the concept of "scheduled agents" which can run on a server in the background and do various maintenance tasks. If these tasks executed with the server's ID it would be necessary to give the server access rights to a lot of databases which would not be very secure. Instead Domino implements a mechanism that these scheduled agents run with the access rights of the user who signed the agent this means that each of the users can run their own version of the agent running with access rights to just their own databases.