Re: [Asrg] Countering Botnets to Reduce Spam

Chris Lewis <clewis+ietf@mustelids.ca> Fri, 14 December 2012 15:08 UTC

Return-Path: <clewis+ietf@mustelids.ca>
X-Original-To: asrg@ietfa.amsl.com
Delivered-To: asrg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id B750821F85C9 for <asrg@ietfa.amsl.com>; Fri, 14 Dec 2012 07:08:53 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.667
X-Spam-Level:
X-Spam-Status: No, score=-0.667 tagged_above=-999 required=5 tests=[AWL=0.381, BAYES_00=-2.599, FH_RELAY_NODNS=1.451, RDNS_NONE=0.1]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id jdihbR2M8tdJ for <asrg@ietfa.amsl.com>; Fri, 14 Dec 2012 07:08:53 -0800 (PST)
Received: from mail.mustelids.ca (unknown [174.35.130.2]) by ietfa.amsl.com (Postfix) with ESMTP id 2655121F85C3 for <asrg@irtf.org>; Fri, 14 Dec 2012 07:08:52 -0800 (PST)
Received: from [192.168.0.8] (otter.mustelids.ca [192.168.0.8]) (authenticated bits=0) by mail.mustelids.ca (8.14.4/8.14.4/Debian-2ubuntu2) with ESMTP id qBEF8mXd021580 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NOT) for <asrg@irtf.org>; Fri, 14 Dec 2012 10:08:48 -0500
Message-ID: <50CB4100.2020408@mustelids.ca>
Date: Fri, 14 Dec 2012 10:08:48 -0500
From: Chris Lewis <clewis+ietf@mustelids.ca>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.8.1.23) Gecko/20090812 Thunderbird/2.0.0.23 Mnenhy/0.7.6.666
MIME-Version: 1.0
To: asrg@irtf.org
References: <SNT002-W143FB9A867C92FA80D90E04C54E0@phx.gbl> <DA14FA4D-13CB-4C61-90C4-4E690F0EC745@blighty.com> <SNT002-W1393526B62C0940EF697B2C54E0@phx.gbl> <20682.3413.665708.640636@world.std.com> <50CA0E91.2080304@mtcc.com> <20682.23612.451287.246798@world.std.com> <50CA805E.3010100@mtcc.com> <50CAA612.3070000@mustelids.ca> <SNT002-W117523E9206C73F54784577C54D0@phx.gbl> <50CABCB4.1030103@mustelids.ca> <20121214133937.GA23699@gsp.org>
In-Reply-To: <20121214133937.GA23699@gsp.org>
X-Enigmail-Version: 1.4.6
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: Re: [Asrg] Countering Botnets to Reduce Spam
X-BeenThere: asrg@irtf.org
X-Mailman-Version: 2.1.12
Precedence: list
Reply-To: Anti-Spam Research Group - IRTF <asrg@irtf.org>
List-Id: Anti-Spam Research Group - IRTF <asrg.irtf.org>
List-Unsubscribe: <http://www.irtf.org/mailman/options/asrg>, <mailto:asrg-request@irtf.org?subject=unsubscribe>
List-Archive: <http://www.irtf.org/mail-archive/web/asrg>
List-Post: <mailto:asrg@irtf.org>
List-Help: <mailto:asrg-request@irtf.org?subject=help>
List-Subscribe: <http://www.irtf.org/mailman/listinfo/asrg>, <mailto:asrg-request@irtf.org?subject=subscribe>
X-List-Received-Date: Fri, 14 Dec 2012 15:08:53 -0000

On 12-12-14 08:39 AM, Rich Kulawiec wrote:

> - Linux systems are not a significant component of botnets.  I've been
> doing passive OS fingerprinting for most of a decade, and they're in
> the noise floor.  It's still true now, as it was years ago, that
> bot-originated spam comes from Windows systems to about six 9's.

If only that were still true.  Sorry Rich.

Compromised Linux machines (mostly servers) are now responsible for ~40%
of all spam.

The actual _count_ of compromised Linux machines is indeed quite low.
Say 62K out of 8.6M observed compromised machines.  About .72%. Two 9's ;-)

But prolific?

I have individual IPs out in the wild that have shoved >1M spams into a
single trap in <48 hours.  I have a copy of one of these bots.  I
periodically run it on a wimpy dual-Atom linux laptop to characterize
what it's sending at the time.  It shoves 65 spams per _second_.

Imagine what a real server could do on industrial grade connections.

And the machine owners don't notice!

> - Better techniques already exist, such a firewalling outbound port 25
> by default and only punching holes for systems that actually need to
> send mail.  Another example: monitoring the TCP connection rate to
> port 25 on remote systems -- spam-senders are likely to push it much
> higher than "normal".

Unfortunately,, getting people to deploy those is worse than pulling teeth.