Security Incidents mailing list archives

Re: China Experience ?


From: euan <j46 () btinternet com>
Date: Wed, 24 Jul 2002 00:10:50 +0000

The fact is, criminally negligent admins who allow their machines to be hacked
and used are not solely limited to the .cn domain. This is an issue which applies
to
everyone. I am not over simplifying the issue. If you cant defend against the
type
of scans which you are getting, then perhaps you should be looking for a new job.

Otherwise, you shouldn't waste your time chasing up every SYN that comes into
your network. Personally I would say a bigger threat is presented by the
thousands
(millions?) of insecure machines sitting on broadband and educational networks in

the US and Europe being constantly scanned and set up as DoS clients.

You cannot say that chinanet is a "menace to the entire internet". This is just
unfairly
tarring a whole country with the same brush, and coming from an american, verges
on hipocrisy and xenophobia. The facts contradict your point of view.

If your machines are secure, and you notice some scans which you know are not
a severe threat, then why bother wasting time and effort trying to report
the perpetrator? Chances are they are using disposable dialup accounts in someone

elses name, and all you do is waste your time and that of the admins at the other

end, only for the guy to move to another network/ISP and continue.

A machine advertising itself by scanning like that surely wont have a long
lifespan
anyway. If you really care so badly, why not take the vigilante role and break in

and rm it?

My attitude is one of sensible packet filtering, sensible levels of logging,
realistic
assesment of threat levels, and ultimately, if they dont break in,then _I dont
care_.

If you are running any sort of public service like a webserver etc, its better to

ignore a few harmless portscans and allow global access, than to potentially
prevent people using your service due to a lack of ability to asses and deal with

threats realistically.

If your network is secured properly, then you have nothing to worry about, and
reporting every person who scans you essentially reduces you to the level of a
busybody.


Erik Fichtner wrote:

On Tue, Jul 23, 2002 at 09:49:13PM +0000, euan wrote:
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?

You're oversimplifying the issue.    Sure, having yet another .cn machine
infected with l10n and trying to scan you for portmapper shouldn't be much
of a big deal to *YOU SPECIFICALLY*. You're patched against that sort of
thing, right?

But... that machine isn't.   That machine is probably vulnerable to a good
20 or more well known simple exploits, as well as the unknown ones that
have been found by True Attackers ....

        .... and it's announcing that fact to the entire friggin world.

Which significantly lowers the bar for attackers to find systems with which
to launder their connections and launch attacks against something, anything,
that might *actually matter*.

Chinanet (and every other ISP in the world that does not deal with network
abuse issues) are a MENACE to THE ENTIRE INTERNET.     You may not lose
because of .cn's apathy, but someone will.

If everyone reading this went out, right now, and found ONE MACHINE in their
logs that is scanning them with some stupid worm infection that's been around
for a year or more, and went through the trouble to hassle the hell out of
the remote ISP until that machine ACTUALLY GOT DEALT WITH, the net would be
a better place for all of us.  (well, except maybe those poor sobs that can't
be bothered to secure their hosts in the slightest that might actually have to
put in a half hour's worth of work to get their ISP to let them pass packets
again.)

...but since that's not about to happen, I guess I might as well just keep
collecting stats on ISP's that don't care about what the hosts in their
netblocks are up to, and filter them out.

--
                        Erik Fichtner; Unix Ronin
                    http://www.obfuscation.org/techs/

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