RE: yahoo mail login security

["Matt Fisher" <mfisher () spidynamics com>]

Don't they revert back to HTTP after auth anyhow ? 
Protect my credentials all you want, but if you give up my email on the
wire(less) I'm switching regardless.  



-----Original Message-----
From: ROB DIXON [mailto:rdixon () workforcewv org] 
Sent: Monday, May 01, 2006 3:51 PM
To: flace9 () gmail com; vanderaj () greebo net
Cc: webappsec () securityfocus com
Subject: Re: yahoo mail login security

If you are capturing the form submission via MITM then would SSL not be
just as trivial via Cain and Able.\

Granted it would be obvious since the SSL cert would appear to be
invalid, but not everyone is that savy.

Robert L. Dixon,  CHFI
State of West Virginia's 
West Virginia Office of Technology
Infrastructure Applications
Netware/GroupWise Administrator
Telephone: (304)-558-5472 ex.4225
------------------------------------------
If you spend more on coffee than on IT security, you will be hacked. 
What's more, you deserve to be hacked. 
-- former White House cybersecurity czar Richard Clarke
> > > Andrew van der Stock <vanderaj () greebo net>  >>>
Several reasons:

1. MD5 does protect the password... as long as it is salted  
correctly. Unsalted MD5 hashes are trivially breakable using rainbow  
attacks, and are unsuitable for most uses (despite heavy usage by  
many programs in exactly this fashion).

2. Replay attacks on public networks. Capturing the form submission  
(trivial without SSL) would allow an attacker to replay the  
conversation and log on as the identity without any issues

3. MD5 is provably weak as a hash - see the work of Wang et al:

http://eprint.iacr.org/2004/199.pdf

4. Javascript on the client is not a trusted environment. Minimizing  
the trust of security weak components is a good design goal.

5. SSL is cheap. A certificate costs less than $100 these days and  
solves many of these issues.

Andrew



On 30/04/2006, at 5:55 PM, Ace123 wrote:

> Clicking on "Why this is secure" link on the yahoo login page gives  
> this:
>
> "Yahoo! now submits your ID and password securely via SSL (Secure
> Sockets Layer) encryption. This means that your personal information
> is more secure every time you sign in.
>
> In the past, Yahoo! used a challenge-response mechanism to protect
> passwords using MD5. Passwords were scrambled using a one-way hash, so
> that they could not be converted to clear text."
>
>
> What could be the reasons why yahoo changed their login security  
> mechanism?
>
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Sponsored by: Watchfire

The Twelve Most Common Application-level Hack Attacks
Hackers continue to add billions to the cost of doing business online
despite security executives' efforts to prevent malicious attacks. This
whitepaper identifies the most common methods of attacks that we have seen,
and outlines a guideline for developing secure web applications.
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