Security Incidents mailing list archives

Re: China Experience ?


From: euan <j46 () btinternet com>
Date: Tue, 23 Jul 2002 21:49:13 +0000

In my experience the majority of network probes I see originate from the USA or
Europe - 99% of the scans originating from .cn or .kr networks are just automated
worm-esque scanners looking for ancient vulns such as wuftp and BIND

Is it really worth blocking an entire country because of a few
trivial-to-defend-against
scans? Do you panic after receiving scans for things like tcp 53 and 21?
Perhaps you should consider changing your IDS policies if you waste so much time
investigating non-issues.

How many of these scans/"hacking" attempts actually led to a successful
comprimise?

Frankly this thread, complete with 11/09 references now, smacks of xenophobia,
and that is indeed a sad thing to see appearing on the internet.



Chris Brenton wrote:

On Tue, 2002-07-23 at 13:24, Alif The Terrible wrote:

      The issue with .cn space is a complete, TOTAL lack of responsiveness
to the everyday issues: spam, scanning, the skript-kiddies who spend *months*
at their Hax0r hobbies without being removed from the networks they inhabit,

Here, here! As someone who used to own/run an ISP, I second this
experience.

I formally gave up on .cn IP space late last year on all networks under
my direct control,

For me it was on 9/11/01. At 3:00 PM EST I started seeing a
semi-coordinated attack against one of my clients (incidents.org) that
involved hundreds of .cn source IP addresses. After 12 hours of chasing
IDS & log detects, my choices where:

1) ban the whole country
2) not go home

I went with #1. ;)

as the effort (several hours a week of reports that
were all completely ignored) simply wasn't worth the return (the one or two
"real" connections a week we had with .cn space).

This was my motivation as well, $$$. The choices where simple, maintain
the ban on China or pay out of my own pocket to hire another security
specialist to do log review. This pretty much made the choice a no
brainer.

      Network operators in China seem to have forgotten that no network is,
or can be, forced to carry anybody's traffic.

Again, I concur. Up till recently .cn was blocked from accessing
sans.org, incident.org, dshield.org, whitehats.ca, 3 financial
institutions and a host of other .org and .com's under my wing. If they
can't play nice why let them play at all.

And if I am going to carry
their traffic, their are going to HAVE to be responsive to my everyday
headaches (when those headaches live on .cn space).

In my spare time I teach the Perimeter track for SANS. One thing I'm
*very* big on with my students is banning subnets that are high
maintenance and provide no value add. For example, if you don't do
business with .cn's, why expose yourself to attack from this source?
True, they can always bounce off of another IP, but this raises the
required skill level and cuts down on much of the noise.

BTW, if anyone is thinking "How do I find out what IP's are in use in
China?", check out:
http://www.idefense.com/Intell/CI022702.html

HTH,
C
--
**************************************
cbrenton () altenet com

find / -name \*yourbase\* -exec chown us:us {} \;

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