Security Basics mailing list archives
Re: 543.rar attachment
From: "Micro Kluge" <microkluge () hotmail com>
Date: Wed, 16 Mar 2005 13:33:49 +0000
Security and Functionality are always the knife edge we walk. Too much of one and we get not enough of the other. Each of our various entities has certain needs and we each have to prune our desires and policies to fit these realities. I am priviledged to have the ability to filter just about any type of file extensions that I wish to. This includes stripping .rar, .zip and .exe's, along with many others, at the gateway. I realize this will not work for everyone, but this strategy is just a part of my defense-in-depth, and has worked quite well thus far.
Cheers, Erik
From: "David J ONEILL" <David.J.Oneill () state or us>To: <kinnell.t () gmail com>, <security-basics () securityfocus com>,<kj6loh () yahoo com>Subject: Re: 543.rar attachment Date: Tue, 15 Mar 2005 10:50:24 -0800 I hope you were being rhetorical in your questions. If not, you clearly do not have enough experience to be discussing what should and should not be allowed via email. As a state agency, we work with many other organizations (large and small), some only have regular email access to work with. 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> 03/15/05 10:44AM >>> Ok let's take it from that standpoint then. All executables are not evil. All computer users are not evil. Does this mean we will shut down our firewalls and let everybody access our internal networks? I'm not saying stop all email traffic, far from it, just all archives. There are many ways of getting archives in. But oh well to each his own. Have you heard of ssh/scp/sftp for deployment of programs? Along with perhaps an email stating where to get your program and how to install it? --- David J ONEILL <David.J.Oneill () state or us> wrote: > 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 us > > > > >>> Jonathan 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 inside > > the > > > rar 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 can > > encapsulate an > > > > executable file should be blocked (IMO). ZIP files are one of > the > > > > biggest carriers of malicious content these days. I don't make > it > > a > > > > habbit of trusting my users no matter how many times they get > > trained. > > > > RAR extraction tools are not part of the software image policy > on > > my > > > > network 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. I > > extracted > > > > the > > > > ---> dddd.exe and ran a scan on it. Norton Corporate 9.01 didn't > > find > > > > ---> anything (as of 4 days ago). I wasn't about to double click > > this > > > > exe on > > > > ---> my corporate network. Block the rar extension on your mail > > server. > > > > ---> > > > > > > > > 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/ > > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > __________________________________ 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 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)