AOH :: HP Unsorted T :: B06-1173.HTM

Trusting smtp



trusting SMTP
trusting SMTP



Oh, sorry for not mentioning earlier -
Operators that want to patch Sendmail, I'd suggest doing it soon. Now we
not only do we face risk to our mail servers, but rather trusting other
servers as well.

This may sound as a joke as SMTP is a not trusted service with no trust in
it, but servers that employ different trust models can potentially be
compromised now.

        Gadi.

On Thu, 23 Mar 2006, Gadi Evron wrote:

> Tech details:
> Sendmail vulnerabilities were released yesterday. No real public
> announcements to speak of to the security community.
> 
> SecuriTeam released some data:
> "Improper timeout calculation, usage of memory jumps and integer
> overflows allow attackers to perfom a race condition DoS on sendmail, and
> may also execute arbitrary code."
> More here: http://www.securiteam.com/unixfocus/5RP0L0UI0S.html 
> 
> ISS only reported the Race Condition (DoS?). The Sendmail Advisory
> reported the Race Condition DoS, the Memory Jumps and a
> "theoretical" Integer Overflow.
> 
> To begin with, anyone noticed the memory leak they (Sendmail) silently
> patched?
> I wonder how many other unreported silently-patched
> vulnerabilities are out there?
> 
> Second, the Integer Overflow is practical, not theoretical.
> 
> ISS reported the Race Condition last mounth. There is NO data available on
> when the other vulnerabilities were discovered. Any guesses?
> 
> They also patched many non-security related bugs, added checks and more
> informative error messages, etc.
> 
> Sendmail is, as we know, the most used daemon for SMTP in the world. This
> is an International Infrastructure vulnerability and should have been
> treated that way. It wasn't. It was handled not only poorly, but
> irresponsibly.
> 
> Here's what ISS releasing the Race Condition vulnerability has to say:
> http://xforce.iss.net/xforce/alerts/id/216 
> They say it's a remote code execution. They say it's a race condition. No
> real data available to speak of. I can't see how it's remotely
> exploitable, but well, no details, remember? From what we can see it seems
> like a DoS.
> 
> Bottom line
> -----------
> What they did behind the smoke-screen is replace a lot of setjmp() and
> longjmp() functions (not very secure ones at that) with goto's
> (interesting choice).
> They changed the logic of the code, replaced everything that calculated
> timeout. Anything that calculated something and returned a value now
> returns a boolean result, when previously they just returned void. They
> used to look at the content rather than success.
> 
> The int overflow is possibly exploitable, not very sure about the
> jumps. No idea why ISS says the Race Condition is, would love insight.
> 
> Public announcement
> -------------------
> FreeBSD were the only ones who released a public announcement of a patch
> and emailed it to bugtraq so far.
> 
> The patches
> -----------
> The FreeBSD patch much like the sendmail.org patch is very long,
> complicated and obscure. The release was made along with a ton of other
> patches for FreeBSD. Go figure what's in there.
> 
> Sendmail.com's patch is so big they may as well have re-released the whole
> program.
> 
> There are also patches available for other *nix systems, no distributions
> released updates yet.
> 
> Sendmail's announcement
> -----------------------
> Obscure. Not worth any other comments other than the ones above.
> 
> CVE information
> ---------------
> CVE-2006-0058 (reserved)
> 
> Commentary
> ----------
> One could say ISS and Sendmail did good, obscuring the information so that
> the vulnerability-to-exploit time will be longer. That proved wrong,
> useless and pointless. They failed.
> 
> After looking at the available data for 30 minutes (more or less), we know
> exactly what the vulnerabilities are. Exploiting them may not be that
> trivial if indeed possible,  but there are most likely already exploits
> out there if it is. When will the first public POC be released? Your guess
> is as good as mine.
> Not to mention the silently patched memory leak.
> 
> SMTP and Sendmail by extension are critical for the Internet as an
> International Infrastructure. If this ends up being exploitable (no
> details, remember?) both ISS and Sendmail should look good and hard at the
> coming massive exploitation of Sendmail servers.
> 
> With issues relating to the Internet Infrastructure I'd be willing to go
> even with the evil of non-disclosure, as long as something gets done and
> then reported publically when it finally scaled down in a roll-back after
> a couple of years.
> If not, and you are going to make it public, make the effort and fix it as
> soon as you can, and give information to help the process of
> healing. Don't do it a mounth late and obscure data.
> 
> It took Sendmail a mounth to fix this. A mounth.
> 
> A mounth!
> 
> With such Vendor Responsibility, perhaps it is indeed a Good Thing to go
> Full Disclosure. It seems like history is repeating itself and Full
> Disclosure is once again not only a choice, but necessary to make vendors
> become responsible.
> 
> I wish we could somehow avoid all the guys who will inevitably shout in
> the press "end of the world". The Internet is, was and will stay
> havoc. There will be exploitation. Those who care about security will be
> patched, those that don't will hopefully finally learn a lesson. The
> Internet won't die because of this, although email may suffer ? but we are
> used to that by now, even when losing money.
> 
> I am so very angry the details are obscure and hidden in the way they are,
> especially as that is useless in this case. Why did they do it, to claim
> they are ?responsible?? Too late.
> 
> "The avalanche has already started. It is too late for the pebbles to
> vote." - Kosh, Babylon 5.
> 
> How are they to show open source is reliable if this is how they act? They
> hurt the cause. If they don't know how to handle something like this, they
> should ask for help.
> 
> What, if it's not reported to Microsoft, there is no reason to be
> ?responsible??
> 
> It's like annoying "fake porn" on TV. Either show the nudity and rate the
> program accordingly or stay suitable for normal viewing. There is no
> eating the cake and leaving it whole.
> 
> "Hey mom, what's my root password? I forgot"
> "Dunno, just use the new sendmail vulnerability!"
> 
> They should learn from Apache. With such a critical vulnerability I know
> the Apache guys would not have slept until it is patched!
> 
> We will update on the situation if required on http://blogs.securiteam.com 
> 
> This text can be found
> here: http://blogs.securiteam.com/index.php/archives/363 
> 
> 	Gadi Evron.
> 
> 


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