Re: Preventing XSS


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Re: Preventing XSS

by ikegami (Patriarch)

on Sep 19, 2007 at 20:11 UTC ( [id://639988]=note: print w/replies, xml )

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in reply to Preventing XSS

Sounds to me like you want

$vars{$_} = HTML::Entities::encode_entities($vars{$_}, '<>&"');
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Quote HTML::Entities,

The default set of characters to encode are control chars, high-bit chars, and the <, &, >, ' and " characters. But this, for example, would encode just the <, &, > and " characters:
$encoded = encode_entities($input, '<>&"');
[download]

It converts plain text into tag-less HTML.

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Re^2: Preventing XSS (sg)
by tye (Sage) on Sep 19, 2007 at 20:48 UTC

Note that I see no reason to encode quote characters here. It isn't like the result is being placed into an attribute value. (:

And I probably wouldn't encode all ampersands since they are useful and rather low risk. If you are worried about the little-supported javascriptish ampersand stuff, then I'd only encode those ampersands. But I guess taking something useful away from users out of combined fear and laziness is not a shockingly rare result.

Which leaves us with a couple of simple regexes and little reason to use a module: