I decided to follow up some of the trail left in the Mark Zuckerberg Facebook fan page hacking incident.

(Update: Facebook tells us that "A bug enabled status postings by unauthorised people on a handful of Pages. The bug has been fixed.")

The only – and best clue – is the link left by the hacker in the status update posted on Zuckerberg's wall, which reads "Let the hacking begin: if facebook needs money, instead of going to the banks, why doesn't Facebook let its user invest in Facebook in a social way? Why not transform Facebook into a 'social business' the way Nobel Price [sic] winner Muhammad Yunus described it? http://bit.ly/f26rT3 What do you think? #hackercup2011"

That contains a bit.ly link. Well, you can find out what the original URL is by adding a plus on the end, so: http://bit.ly/fs6rT3+ From which we can see that about 17,000 people clicked the link. Not bad (though we have to say that Julian Assange gets more clicks when he appears on the Guardian ... but we digress).

The original, shortened link was actually: http://en.wikipedia.org/wiki/Social_business?h=d044aeb71f4e466a552708fc6e3863ef

&thanksforthecup=

https://www.facebook.com/photo.php

%3Fpid%3D393752%26id%3D

133954286636768%26fbid%3D170535036312026

Let's begin with the second part of the long link – the part that starts "thanksforthecup": it's URL-encoded (so "%3D" actually stands for the character "=", "%26" for "&") and leads to a Facebook photo page for the Hacker Cup, a competition run by Facebook itself. So the hacker is saying he thinks he should get the cup. OK, we get it.

Now, back to the first part. If you just click the link, you'll be taken to Wikipedia's page about social business. But not the latest version – to a specific version in its edit history.

That version was up for two minutes. That version leads to a web consultancy in the US mid-west. I have contacted the owner who emphatically denies that he had anything to do with it, and I have no reason to doubt him as IP addresses are easily spoofed.

Crucially, the edit was only on Wikipedia for two minutes on Tuesday 25 – between 19.17EST and 19.19EST – suggesting that whoever must have created the edt with the link and then deleted it straight afterwards, but kept the link to the version he had edited. Then he or she encoded the link for the photo and attached it to the Wikipedia link, and stuffed the whole lot into bit.ly. Then, having got the shortened link, he or she went and updated the status on the fan page.

In other words, we might be able to find the hacker if we can find out who changed the Wikipedia page. Unfortunately, it wasn't done by a registered user. But because of Wikipedia's clever tracking system, you can see the IP of non-registered users: there it is at the top of the edit page in the screenshot: 131.74.110.168. You can also see what articles machines at that IP address have edited – a very mixed bag–- and also how edits from that IP have been increasingly smacked down by Wikipedia editors (latest on that page coming from October 2009: "Please stop your disruptive editing. If you continue to vandalise Wikipedia, as you did at Lyoto Machida, you will be blocked from editing."

So who's behind 131.74.110.168? A quick whois query tells you that it is... the US department of defence in Williamsburg.

In other words: this might be someone in the military. Most likely those edits don't come from one person – they come from all sorts of people in the Williamsburg location. Or, just as possible, it was someone who had hacked into the computers there from outside (not as difficult as you'd hope it would be) and is using them as a proxy to make the Wikipedia edit, and, quite possibly, hack Zuckerberg's page. (We've asked Facebook whether Zuckerberg's page was accessed from that IP, but haven't had an answer yet.)

Updated to add Facebook comment, clarify that it's original Guardian investigation, grammatical tidying.



• This article was amended on 27 January to clarify that there is no clear indicaton as to who the hacker is.