RE: SQL Slammer - lessons learned

[John.Airey () rnib org uk]

> -----Original Message-----
> From: Nicob [mailto:nicob () nicob net]
> Sent: 06 February 2003 10:42
> To: full-disclosure () lists netsys com
> Subject: RE: [Full-disclosure] SQL Slammer - lessons learned
>
>
> On Wed, 2003-02-05 at 16:38, Paul Schmehl wrote:
>
> > Can you think of a legitimate reason why ISPs should allow ports
> > 135-139/TCP/UDP to be open to the Internet?  How about port 
> 445/UDP? 
>
> IMO, it's not to the ISP to choose wich ports and services 
> should I use.
> I pay it (sort of) for a pipe running from my home-computer 
> to the wild
> Internet and *that's all*.
>
> I don't want some "services" like transparent proxies, AV scanning at
> the mail relay or port filtering. I just want a pipe ...
>
> > What about the ISPs whose policy it is to not allow
> > customers to run servers?
>
> That's another problem.
>
> If I ask for a pipe, I want a pipe.
> If I ask for a discount ADSL access with limited amount of 
> trafic and no
> allowed hosting (HTTP, FTP, SMTP, SSH, ...), the ISP can restrict the
> inbound ports.
>
> If the next big vuln/worm is a SSH one, would you agree with an ISP
> blocking inbound TCP/22 and forbidding to users to connect to their
> home-LAN to check mails, get some files, start the 
> coffe-maker or manage
> downloads ?
Not at all, especially when that would stop me tunnelling VNC through SSH,
a lot cheaper than PC/Anywhere!

We've drifted from my original point, that ports used dynamically by IP
stacks should be distinct from service ports, so that ISPs or administrator
CAN block them without impacting the end user if they so wish. At the minute
we need stateful filtering to rescue us from the port allocation mess we are
in. SQL Slammer was only as successful as it was because stateful filtering
isn't widespread, ie this one got past many administrators of large networks
who are already careful about which services are publicly available.

Given the choice between controlling traffic at the border or keeping
thousands of "non-public" machines up to date, I know which I'd choose.

- 
John Airey, BSc (Jt Hons), CNA, RHCE
Internet systems support officer, ITCSD, Royal National Institute of the
Blind,
Bakewell Road, Peterborough PE2 6XU,
Tel.: +44 (0) 1733 375299 Fax: +44 (0) 1733 370848 John.Airey () rnib org uk 

Am I the only person in the UK who finds it strange that our Prime Minister
complains of Human Rights abuses around the world, yet wishes to opt out of
the European Convention of Human Rights?

- 

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