Re: [fw-wiz] Variations of firewall ruleset bypass via FTP

From: Darren Reed (darrenrat_private)
Date: Sat Oct 12 2002 - 08:52:06 PDT

  • Next message: Dave Piscitello: "Re: [fw-wiz] Tunnel intruder"

    I know you want this to die, but I've posed some more questions for you
    to think about :)
    
    In some email I received from Paul D. Robertson, sie wrote:
    [...]
    > In my mind, saying "Not vulnerable" and just relating that to the POC code 
    > is bad because it makes people think they're safe when they may not be, so 
    > if this is indeed the case, I think we'd all appreciate a more verbose 
    > clarification.
    
    So what do you do ?
    The last N versions since 1 Jan 2000 ?
    Just test your current/latest version ?
    Poll your userbase and check every version that's in use everywhere ?
    
    As it happens, IPFilter was fixed before I got any information about
    this at all from CERT.  But that is of no help to anyone not running
    the latest version.  Then again, you need to be running a certain
    make & model of ftpd before it's a problem as well.
    
    > > Unfortunately the people behind security-officer for NetBSD have been 
    > > next to useless in this case and if you asked me, their largesse in
    > > this case would be a good excuse to give them all the ass (it's not
    > > a fun job, either.)  FreeBSD has not been much better.
    > 
    > Frankly, that's *why* we're looking to you.  You're the #1 IPF authority- 
    > no matter what version *they* ship.   If you need someone to generate 
    > pages of rants pointed at them, I'm obviously qualified ;)
    
    Like I keep trying to say, if I don't get the right information then
    there's not much I can do or say to provide the right help to people.
    For whatever it's worth, I depend on them to provide me with information
    that gets passed to them from CERT.  What I guess I'm saying here is
    that because I had no direct contact with anyone useful in this, looking
    to me, now, is pointless.  I kind of get the impression that IPfilter
    may have been the only popular product that did have an issue and yet
    you'd be forgiven for thinking it was a complete afterthought the way
    some people acted.  If there had of been some sort of direct communication
    between me and CERT/ICSA/Mikael before this week then maybe things would
    have worked out better.  CERT at least appears to have learnt a thing or
    two from this.
    
    [...]
    > "I understand the class of attack, and I know IPF isn't vulnerable, 
    > because I've looked at what I'm doing and compared it to the partial ACK 
    > issue."
    > 
    > "I understand the class of attack, and I know that I've fixed this in the 
    > current version of IPF, older versions are probably vulnerable, but I'm 
    > not saying that explicitly."
    > 
    > "I ran the proof-of-concept code and it didn't work, so I'm going to say 
    > IPF isn't vulnerable until someone proves otherwise."
    
    All of these.
    It was hard enough to even compile the damn PoC code.  Plus:
    
    "It looked like the proof-of-concept code required a special agent on the
     inside and if that's the case then I cannot protect against that."
    
    All in all, I think I'd rather try and make some sort of celestial
    alignment try and happen than have to go through all that again.
    From start to end, it's been one big f*cked experience.
    
    Darren
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