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Re: Quarantine your infected users spreading malware
From: Radoslav Dejanović <radoslav.dejanovic () opsus hr>
Date: Wed, 22 Feb 2006 09:27:02 +0100

On Monday 20 February 2006 22:40, Gadi Evron wrote:

Some who are user/broadband ISP's (not say, tier-1 and tier-2's who
would be against it: "don't be the Internet's Firewall") are blocking
ports such as 139 and 445 for a long time now, successfully preventing
many of their users from becoming infected. This is also an excellent
first step for responding to relevant outbreaks and halting their

Philosophy aside, it works. It stops infections. Period.

Umm.. sorry, but it doesn't. :-)

While blocking ports 139 and 445 does help in reducing the number of infections, it doesn't stop them. We have here 
mostly user-friendly ISP's that offer antivirus and antispam protection along with blocking ports (turned on by 
default, and people don't know they can change that), but that just reduced the speed of spreading and gave some more 
protection to users, but people here still get infected, despite antivirus and port blocking. 
Antivirus software can't cope with brand new virus/worm/malware until it is detected and signature is distributed, so 
there's always a small chance you might get another e-mail that passed the checkpoints. And users are... umm... 
(searches google for polite variations of "idiot") ... gullible - they will just click on that "free sex" icon. 

The other part of the problem is that ISP's (in my country, at least) usually do not offer such services for their 
lease-line customers, or they charge them pretty penny for such services. Users on leased lines are up to their own 
defences, which in many cases mean they have little to no defences.

Radoslav Dejanovi?
Operacijski sustavi d.o.o.
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