Security Basics mailing list archives
Re: 543.rar attachment
From: "David J ONEILL" <David.J.Oneill () state or us>
Date: Tue, 15 Mar 2005 08:25:47 -0800
And your point is .... Not all executable files are evil, the source of the file must be considered. Sometimes, such as client server applications, executable files must be deployed with the associated resource files. And with the limitations on attachment sizes placed on commercial email systems, one needs all the compression one can get. David J O'Neill Senior Systems Analyst State of Oregon Department of Human Services Office of Information Services PH# 503.378.2101 ext. 280 email david.j.oneill () state or us
Jonathan Loh <kj6loh () yahoo com> 03/14/05 10:41PM >>>
Ok let's have a reality check. Blocking archive files is easy by just writing a simple filter looking for various extensions. Pruning executable files means you will have to use that same filter, open the archive, either extract the whole thing, delete the executables, and repackage the whole thing, or delete the executables in place. Everyone can split large application files, or can be taught how, and send them to be repackaged. Ever wonder how TCP and UDP work? --- David J ONEILL <David.J.Oneill () state or us> wrote:
Gee, why not just block ALL email communication. That would save
you
some work too. Archive files are a necessary part of communication and very
beneficial
in saving bandwidth. Let's have a reality check .... David J O'Neill Senior Systems Analyst State of Oregon Department of Human Services Office of Information Services PH# 503.378.2101 ext. 280 email david.j.oneill () state or usJonathan Loh <kj6loh () yahoo com> 03/14/05 02:21PM >>>Ok that's a solution. But what I want to ask you is this. How much overhead does it take to do this? Blocking archive files would be an easier method with little overhead. Possibly with a reply to sender that your site
does
not accept archive files. --- Kinnell <kinnell.t () gmail com> wrote:On the network I'm a member of we block all exe files sent insidetherar or zip, so even if it is sent the file will be 0byted.
Wouldn't
that be a better method? otherwise if you block all bz2, zip,
rar,
etc... then you will block a lot of useful communication -Kinnell On Fri, 11 Mar 2005 16:49:16 -0500, adisegna () siscocorp com <adisegna () siscocorp com> wrote:Sean, I have to disagree with you. Any file that that canencapsulate anexecutable file should be blocked (IMO). ZIP files are one of
the
biggest carriers of malicious content these days. I don't make
it
ahabbit of trusting my users no matter how many times they gettrained.RAR extraction tools are not part of the software image policy
on
mynetwork so users are oblivious to the file blocking. What is
your
solution? Thanks AD Information Technology Group Security Identification Systems Corporation -----Original Message----- From: Sean Crawford [mailto:sean01 () accnet com au] Sent: Tuesday, March 08, 2005 9:39 PM To: security-basics () securityfocus com Subject: RE: 543.rar attachment ---> -----Original Message----- ---> From: adisegna () siscocorp com [mailto:adisegna () siscocorp com]
---> Subject: RE: 543.rar attachment ---> I just recently got the same executable inside .rar. Iextractedthe ---> dddd.exe and ran a scan on it. Norton Corporate 9.01 didn'tfind---> anything (as of 4 days ago). I wasn't about to double clickthisexe on ---> my corporate network. Block the rar extension on your mailserver.---> rar is a valid compression format...blocking it isn't a very
good
solution. 2 cents. Sean__________________________________ Do you Yahoo!? Yahoo! Small Business - Try our new resources site! http://smallbusiness.yahoo.com/resources/
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Current thread:
- Re: 543.rar attachment, (continued)
- Re: 543.rar attachment Kinnell (Mar 14)
- Re: 543.rar attachment Steven DeFord (Mar 14)
- Re: 543.rar attachment Kinnell (Mar 14)
- Re: 543.rar attachment Jonathan Loh (Mar 14)
- RE: 543.rar attachment adisegna (Mar 14)
- Re: 543.rar attachment David J ONEILL (Mar 15)
- RE: 543.rar attachment Sean Crawford (Mar 16)
- Re: 543.rar attachment Jonathan Loh (Mar 15)
- Re: 543.rar attachment Kinnell (Mar 15)
- Re: 543.rar attachment Jonathan Loh (Mar 15)
- Re: 543.rar attachment SAMIR SHUKRI (Mar 16)
- Re: 543.rar attachment Kinnell (Mar 15)
- Re: 543.rar attachment David J ONEILL (Mar 15)
- Re: 543.rar attachment Jonathan Loh (Mar 15)
- Re: 543.rar attachment David J ONEILL (Mar 15)
- Re: 543.rar attachment Micro Kluge (Mar 16)
- FW: 543.rar attachment adisegna (Mar 16)
- RE: 543.rar attachment adisegna (Mar 16)