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Re: [Mutt] #2846: Security vulnerability in APOP authentication



#2846: Security vulnerability in APOP authentication

Comment (by Rocco Rutte):

 {{{
 Hi,

 * Brendan Cully [07-04-02 15:31:14 -0700] wrote:
 >On Sunday, 18 March 2007 at 17:36, Rocco Rutte wrote:

 >>  I was looking at some mutt code for this issue and other issues that
 >>  report broken threading upon invalid message-ids. It seems that mutt
 >>  happily accepts the following syntax: '<.*>' which is just plain
 wrong.

 >>  I looked at rfc822.c to try to reuse address parsing for parsing
 >>  message-ids but failed since I didn't have much time and the quote is
 >>  quite complex.

 >>  Even though adopting your code for mutt would be quite easy, I'm not
 >>  yet sure what to do in case of validation errors.

 >>  Say we get '<foobar>' during APOP authentication; should be really
 >>  reject that and report failed authentication? If a message has
 >>  '<foobar>' as message-id and others have it in their References:
 >>  header, should we really ignore it and break threading?

 >Here's a patch that does a really minimal check that the message ID is
 >of the form <x@y> where x and y are between ASCII 0 and 127. I hope
 >that it's enough to thwart the MD5 collision attack, but liberal
 >enough to tolerate the range of broken POP servers out there. The @y
 >test could be easily removed if necessary.

 >Comments?

 Adding a new method is one way, I hoped to find some way to reuse the
 address parser. But as that's quote complex, I think it's okay for now.
 The only thing I saw was that checking for 'l>127' is probably not
 enough as you also want to check for 'l<32'.

    bye, Rocco
 }}}

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Ticket URL: <http://www.mutt.org/ticket/2846#comment:>