On 8/23/12 8:30 PM, "Mark Foster" <[email protected]> wrote:

> 
> Hi folks
> First time poster, please indulge me as I get to grips with how this
> group works....
> 
> I have had a case recently where a customer of my mail platform
> (protected with Clam) received an encrypted zip attachment.
> The body of the message immediately prior to the Base64 encoded
> attachment contained the word 'password' (twice, infact) and the email
> was subsequently blocked as containing "Worm.Bagle.F-zippwd-7"
> 
> The email was clean. With a raw copy of the email I was able to strip
> out the entire contents, short of the attachment and the two lines of
> text prior.
> 
> By removing all trace of the word 'password' in those two lines, the
> file ceased to be marked false-positive for the virus.
> 
> It appears that the conditions to match the above virus definition
> (encoded attachment, and the presence of the word 'password' in the
> preceding text) are pretty vague.

You can see the string using the following command:
sigtool --find Worm.Bagle.F-zippwd-7 | sigtool --decode-sig

You can also go to <http://clamav-du.securesites.net/cgi-bin/clamgrok> and
type in the name, then translate each string to ASCII, but I find the above
easier.

I see six different strings that must be present in order to identify this
one.  It's also in the main.cvd indicating it's been around for awhile.

> I submitted this as a false positive
> several days ago but it appears to still trigger, so i've been forced to
> have a bypass for Clam worked in for this customer (less than ideal).
> 
> Interested in others exposure to circumstances like this, wonder if i'm
> alone in seeing this behavior (or similar) and what the best method of
> moving forward is?
> 
I suspect you've done all you can.  Perhaps one of the signature writers can
tell you what the final decision was/will be.


-Al-
 
-- 
Al Varnell
Mountain View, CA



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