Re: [malware-list] scanner interface proposal was: [TALPA] Intro to a linux interface for on access scanning

[David Collier-Brown <davecb@sun.com>]

tvrtko.ursulin wrote:
>>Huh? I was never advocating re-scan after each modification and I even 
>>explicitly said it does not make sense for AV not only for performance but 
>>because it will be useless most of the time. I thought sending out 
>>modified notification on close makes sense because it is a natural point, 
>>unless someone is trying to subvert which is out of scope. Other have 
>>suggested time delay and lumping up.

Alan Cox wrote: 
> You need a bit more than close I imagine, otherwise I can simply keep the
> file open forever. There are lots of cases where that would be natural
> behaviour - eg if I was to attack some kind of web forum and insert a
> windows worm into the forum which was database backed the file would
> probably never be closed. That seems to be one of the more common attack
> vectors nowdays.

  I suspect we're saying "on close" when what's really meant is
"opened for write". In the latter case, the notification would tell
the user-space program to watch for changes, possibly by something as
simple as doing a stat now and another when it gets around to 
deciding if it should scan the file. I see lots of room for
user-space alternatives for change detection, depending on how much
state it keeps. Rsync-like, perhaps?

--dave
-- 
David Collier-Brown            | Always do right. This will gratify
Sun Microsystems, Toronto      | some people and astonish the rest
davecb@sun.com                 |                      -- Mark Twain
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