Full Disclosure mailing list archives

RE: TinyURL


From: "Ricky Blaikie" <ricky.blaikie () servercity co uk>
Date: Wed, 29 Oct 2003 17:47:23 -0000

Can we now agree that this is not an ideal medium for passing sensitive
information?

Surely anyone with an iota of common sense would realise that this would not
be a 'good thing(tm)'?

Hence, we veer wildly into the 'mostly irrelevant' category ;-)

Cheer all,
--
Ricky Blaikie - Server City Ltd
TEL: 0871 2601000 : FAX: 0871 2601001 : http://www.servercity.co.uk
Visit our website for latest offers and pricing or e-mail me.

-----Original Message-----
From: full-disclosure-admin () lists netsys com
[mailto:full-disclosure-admin () lists netsys com]On Behalf Of Kenton Smith
Sent: 29 October 2003 17:05
To: Joel R. Helgeson
Cc: full-disclosure () netsys com
Subject: Re: [Full-disclosure] TinyURL


I would say if your passing sensitive information you shouldn't use this
service anyway. Even if they randomized it, there's nothing stopping
someone from just randomly entering URL's. I'd stumble upon your
sensitive information eventually. It's fine for passing news stories and
Ebay links, but I wouldn't use it for much else.

Kenton

On Wed, 2003-10-29 at 04:19, Joel R. Helgeson wrote:
This is an information leak rather than a real vulnerability. I thought it
might be of interest to others...

www.tinyurl.com is a website that will convert a long url to a short one.
If
you want to email a link to say, driving directions on mapquest, the url
is
rather long and will get broken up. Tinyurl will store that long link, and
give you a short one that looks like: http://tinyurl.com/abcd

It appears that the last four letters are incremented one letter at a
time,
so my URL may be aaaa, then aaab, and so forth.
If people are using the tiny URL service to pass along URL's to sensitive
information, it is easy to guess these URL's.

I recently sent an email to someone with a tinyurl, and decided to change
one character in the url and came across a link to a kiddie porn site...
http://tinyurl.com/stab

Its a coincidence that stab is a word, but its just a few characters off
from my URL, staa & stac are also valid URL's.

The TinyURL service should use a randomly created string, rather than one
that is incremented by one character.  Regardless, users of this service
could have the information they intend to share with others viewed by
anyone
that types in the string.

Thoughts?

Joel R. Helgeson
Director of Networking & Security Services
SymetriQ Corporation

"Give a man fire, and he'll be warm for a day; set a man on fire, and
he'll
be warm for the rest of his life."

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