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Zip files

We are getting some spam emails that are making their through the ASG to the ends users pc's that contain zip files. The users, not knowing any better (b/c the email come from "delta or USPS") open the zip file, only for it to contain a virus. IS there a way to combat this?


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  • Make sure your anti-spam is configured correctly -- RBL / missing RDNS blocking, etc. all help.  As far as bad attachments -- there will always be the odd 0-day file that won't be detected by the AV engines -- in the end, user training is key.

    CTO, Convergent Information Security Solutions, LLC

    https://www.convergesecurity.com

    Advice given as posted on this forum does not construe a support relationship or other relationship with Convergent Information Security Solutions, LLC or its subsidiaries.  Use the advice given at your own risk.

  • i jsut block zip files..[:)]

    Owner:  Emmanuel Technology Consulting

    http://etc-md.com

    Former Sophos SG(Astaro) advocate/researcher/Silver Partner

    PfSense w/Suricata, ntopng, 

    Other addons to follow

  • Hi All,
    I have noticed this also. Blocking .zip files is also not a solution we recieve bills that are packed in a .zip.

    user training and desktop AV software has kept us safe at untill now though.
  • hi Folks,

    i´ve noticed this case, too.
    We´ve got mails with zip file, which were NOT RECOGNIZED NOR BLOCKED by Astaros scanner. If i save the zip attachment locally, my AV Scanner (Sophos!)
    alarms me and blocks the file.
    Sophos alerts the inside exe file as'Troj/Gimemo-A'

    Any ideas? (no! blocking zip files is´nt a workaround)

    CU
    Thomas
  • I second this!
    If there were at least a way to block *.exe and *com in a zip file. 
    In fact, I suggest that any of the blocked file extensions should really trigger just as well when found inside a*zip or other archive file. Anybody wanting to use zipping in order to circumwent extension checks should at least use encrpyted archives

    cu
    Hagen
  • if the utm scanner isn't scanning inside the archives this is a huge hole that's pretty easily solved as the engines in the utm support scanning inside archives on the desktop...which means they contain the ability to do this natively..it's time to tighten up the UTM security.

    Owner:  Emmanuel Technology Consulting

    http://etc-md.com

    Former Sophos SG(Astaro) advocate/researcher/Silver Partner

    PfSense w/Suricata, ntopng, 

    Other addons to follow

  • I second this!
    If there were at least a way to block *.exe and *com in a zip file. 
    In fact, I suggest that any of the blocked file extensions should really trigger just as well when found inside a*zip or other archive file. Anybody wanting to use zipping in order to circumwent extension checks should at least use encrpyted archives

    cu
    Hagen


    encrypted archives should be blocked at the gateway....if they can't be scanned then use another solution like secure portals..not e-mail.

    Owner:  Emmanuel Technology Consulting

    http://etc-md.com

    Former Sophos SG(Astaro) advocate/researcher/Silver Partner

    PfSense w/Suricata, ntopng, 

    Other addons to follow

  • If any of you has an example and paid support, please open a ticket.  I believe that the AV scanner is supposed to look inside zip files unless they are password-protected.

    Beyond that, I agree with Bruce that users should be trained, with Thomas that any unexpected file should be saved and scanned before opening and with William's implication that it's irresponsible to send zip files in emails.  Any company that sends invoices in zip files is irresponsible.

    Cheers - Bob
     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • Hello,

    i have here nearly the same problem... i block .exe and executable files via mime type filter,
    but as example ... i rename netviewer.exe to netviewer.doc then i .zip'it 
    smtp.log
    ----- 
    2012:06:15-10:11:10 fwsrv1-2 smtpd[15032]: SCANNER[15032]: 1SfRcc-0003uS-7v myemail@mail.com R=1SfRbb-0003pT-2T P=INPUT S=11201653
    2012:06:15-10:11:18 fwsrv1-2 smtpd[15032]: SCANNER[15032]: id="1000" severity="info" sys="SecureMail" sub="smtp" name="email passed" srcip="1.1.1.1" from="myemail@mail.com" to="yourmail@mail.com" subject="test netviewer.zip" queueid="1SfRcc-0003uS-7v" size="11201653"
    2012:06:15-10:11:18 fwsrv1-2 smtpd[15032]: SCANNER[15032]: 1SfRbb-0003pT-2T => work R=SCANNER T=SCANNER
    2012:06:15-10:11:18 fwsrv1-2 smtpd[15032]: SCANNER[15032]: 1SfRbb-0003pT-2T Completed



    -----
    it comes truh my astaro mail av proxy... that is not nice.
    Anything i can do?

    Cheers

    Ferdinand
  • rut roh...this is most assuredly a problem.

    Owner:  Emmanuel Technology Consulting

    http://etc-md.com

    Former Sophos SG(Astaro) advocate/researcher/Silver Partner

    PfSense w/Suricata, ntopng, 

    Other addons to follow