Phishing detection gets confused by malformed HTML

[John Wilcock]

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Julian Field wrote:
> John Wilcock wrote:
>
>> If you have a bit more time for phishing mods, how about the two false
>> positive cases I reported in January?
>>
>>> Click here to <a href="http://www.example.com/">visit
>>> www.example.com</a>
>>
>>
> Only looking at the last "word" in the text is a dodgy thing to do as
> spammers could completely defeat it by putting in 1 space in the text,
> and most users wouldn't notice the extra space.

Hmm. I hadn't thought this through enough.

I was going to suggest looking at the only "word" that "looks like" a
URL, but then I realised that there are cases like

<a href="http://phisher.com"/><span style=invisible>
phisher.com</span>yourbank.<span style=tiny> </span>com</a>

I can't see any way you could detect things like that and worse, yet not
trigger on my example above. Forget I asked - you're one step ahead of
most of us as usual.

>>> <a href="http://www.example.com/">all about .net technology</a>
>>
>>
> Look for .net with a space both sides of it? It would help but wouldn't
> be a complete solution by any means.

It would have to be .net with a word-separator either side, in case the
".net" is at the beginning or the end of the text.

And even that might be open to abuse by phishing for .net domains.

John.

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