EEYE: Yahoo! Mail Account Filter Overflow Hijack
"Yahoo! Mail" Account Filter Overflow Hijack
Release Date:
April 19, 2004
Date Reported:
March 10, 2004
Severity:
High
Vendor:
Yahoo!
Description:
"Yahoo! Mail" is one of the Internet's most popular
web based email solutions. They provide free email and
large capacity storage, as well as subscription-based
services such as mail forwarding, expanded storage and
personalized email addresses.
eEye Digital Security has discovered a security hole in
"Yahoo! Mail" which allows a remote attacker to take over
an account remotely by sending a specially crafted email.
Technical Description:
-----------EXAMPLE EMAIL---------
SCRIPT
[->a bunch of chars here [spaces are most stealth], the whole
file size will be just about 100KB]
[this causes the filter to not work... the code is then run
automatically]
---------------------------------
The pseudo-diagram above explains the scenario rather well.
For whatever reason, Yahoo's email filter simply does not
work on files which exceed a certain range. This kind of
software issue is relatively common.
A remarkable note about this bug is that no one seems to
have found it before.
As far as anyone knows.
Drew's Happy-Happy Quote for the Day:
Ben Franklin, "Three can keep a secret if two are dead."
Protection:
Yahoo! Mail is a hosted, web based service, hence users
do not need to patch. Yahoo has already fixed this bug,
therefore all Yahoo accounts are now completely safe from
it.
Vendor Status:
Yahoo! has been notified and has rectified the issue.
Credit:
Drew Copley, eEye Digital Security (dcopley eeye.com), Research Engineer
thanks to "http-equiv" for additional research
Related Links:
Retina Network Security Scanner - Free 15 Day Trial
http://www.eeye.com/html/Products/Retina/download.html
Greetings:
To all of you out there that don't use turn signals.
Sooner or later your time is going to come. And a special
greeting to all of these competitors of ours making some extra
cash by selling pre-fix vulnerabilities through pay for play
"mailing lists". I am sure North Korea, the Yakuza, the
"Triads", the Russian Mafiya, La Costa Nostra, and every
other criminal state or organization appreciates your type of
"Partial Full Disclosure for a Darn Good Price" motto.
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