Subject: [asrg] 6. proposal of solution: Using Relay Honeypots to Reduce Spam

From: Brad Spencer <[email-masked]>
Date: Tue, 15 Apr 2003 06:51:19 -0500

ASRG and the end of spam

This started as a honeypot proposal and still ends with a honeypot 
proposal.  Along the way it grew.  the growth portion is now first.

ASRG was created to deal with the spam problem.  The proper way to deal 
with the spam problem is to end it, to end spam.  ASRG has considerable 
influence that it can use to help bring about such an end.  People expect 
it to make a proposal to end spam: if the proposal appears reasonable and 
workable people and organizations that want spam to end will cooperate in 
the effort to end spam.  This means that if ASRG provides a framework for 
action at several levels by several kinds of participant the action is very 
probably going to happen.  the ASRG proposal can anticipate cooperation 
from more than just those participating in ASRG and the organizations 
represented by those participating in ASRG.   As an important corollary, if 
the spammers see that ASRG has formulated a plan and that internet forces 
are cooperating to bring that plan to fruition the spammers should conclude 
that the ASRG will succeed and that they will ultimately be stopped from 
spamming by the ASRG plan.  That's perhaps difficult to assert or believe 
in the present environment but it should be clear that the described 
situation (spammers see no hope) should be the goal, if it can be 
attained.  Part of the purpose of the ASRG is to determine a plan of 
action, part of the purpose is to determine how successful that plan of 
action will be and part of the purpose is to maximize the results of the 
plan of action, as finally formulated.  What follows is presented as though 
it were that plan.  What finally results may bear a great resemblance to 
this proposal or may completely supplant it.  What matters is whether the 
final plan will be very likely to work, and will attract support from those 
whose support may be necessary for success, will convince the spammers that 
the days of spam are ending.

It is important to think of the scope of operations that ASRG can 
stimulate.  The spam problem can be analyzed into its component parts, ASRG 
can make proposals for each entity that might act against a particular 
component of spam.  There need not be a single, monolithic approach to 
ending spam.  If the proposed actions are reasonable (and part of the ASRG 
task is to search for the most powerful reasonable proposal) then the 
entities asked to take the actions very probably will take action.  (Note 
that the same reasoning suggested for the spammers applies to the ISPs that 
are in any degree spam supporters: there is very great reason to not want 
to be the ISP that was last to end its spam-support activities.  One ISP 
will be: the goal is to motivate such ISPs to change behavior well before 
the end.  If the end is coming and the profit can be seen to be coming to 
and end anyway the smarter path is to become vividly anti-spam.)

The ASRG solution can be comprehensive, can cover several stages of 
operation.  ASRG can anticipate that some spammers, at least for a while, 
will resist the effort to end spam and will attempt to overcome the ASRG 
methods.  While the ASRG proposal should be comprehensive enough to 
anticipate such moves the details of such moves cannot be 
anticipated.  ASRG must, therefore, be prepared to modify or augment their 
program, as new evidence of spammer evasion becomes known.  Again, the 
standard for action must be that it is action that will succeed: the new 
proposals of the ASRG should be convincing to those who will be asked to 
extend their efforts in order to thwart the modified spammer behavior.  In 
short, the ASRG should continue watching the spam process and should be 
quick to analyze new spammer tricks and to devise ways to combat those 
tricks and incorporate whatever changes are needed into their plan.

"Entities" denotes classes of those who can take actions specific to their 
position to help end spam.  ISPs that harbor spammers are an entity, ISPs 
in control of resources spammers abuse are an entity, ISPs that are at the 
target end of spam are an entity.   End users whose systems are abused to 
send spam are an entity, anti-virus companies are an entity.  Software 
companies and freeware providers may have a function in the final ASRG plan 
- they could make available any tools called for by the ASRG 
proposal.  These entities obviously may overlap.  the important point is 
that different actions can be taken at different points in the spam pathway 
and that the ASRG solution can, if necessary, call for action at many 
points, with the actions being those specific to the point.  It is quite 
likely that part of the final ASRG comprehensive plan will be a call for 
the continuation and perhaps intensification of existing anti-spam 
techniques.  The goal is not novelty but is the eradication of spam.  ASRG 
can provide a framework and mechanism to enhance the interaction of 
anti-spam forces and to intensify the targeting of specific aspects of the 
spam problem.  While not an "entity" as defined above the press and media 
may be important to the ASRG solution.  It's not enough that principles and 
methods be agreed upon: action must be taken by sufficient numbers of the 
people and organizations with the power to take action that success results.

The first analysis of spam is easy: spam has two types, direct, and 
non-direct.  Direct spam should be completely controllable by use of block 
lists, at least direct spam from spam-only sources.  (Filters may also 
identify and stop direct spam - there seems little reason to consider 
abandonment of filters as anti-spam tools and the redundancy of the filters 
provides backup for the blocklists in the case that the spammer gets a new IP.)

The rest of spam, non-direct spam, has a dual nature: it is both spam and 
is also the product of abuse.  Much of the abuse is possible because of the 
original model of the internet in which each user of the internet was 
assumed to be trustworthy.  That trust is now often misplaced.  The 
attempted solution to the loss of trust has mostly been to make individual 
systems no longer trusting (firewalls, secure MTAs, etc.)  That has worked 
(for the most part) for individual systems but has not cured the overall 
problem of abuse.  The common protections against abuse are passive and 
actionless.  As such they create little incentive for the abandonment of 
abusive behavior.  Perhaps ASRG can make a significant contribution by 
examining whether this single-system-centered passive approach is effective 
and appropriate.  (Looking ahead)  honeypots are also passive but differ 
from the traditional approach in that there are actions inherent in the 
operation of the honeypot and that further actions may be taken based on 
the results of the honeypot.  (In the broadest view honeypots are action 
against a specific form of abuse and can expand beyond the single-system 
limit.)

A honeypot (particularly an open proxy honeypot) can be a man-in-the-middle 
defense.  The spammer attempts to contact some resource through the open 
proxy honeypot.  The open proxy honeypot could simulate that contact or it 
could allow it.  In the SMTP dialog with the spammer's intended target the 
open proxy honeypot could function exactly as desired, with one 
exception.  After the data has been transferred to the SMTP server 
contacted through the honeypot the honeypot could silently add an RSET to 
the transaction (other schemes to disrupt the communication are possible - 
the point is that it looks real and is real, with the exception that the 
result is nil.  The open proxy honeypot could RSET after all recipients are 
specified and then create a single recipient of abuse@<the target>.)  To 
the spammer it will appear as though everything functioned as normal - it 
did.  The important exception is that the spam did not go through - it was 
obliterated.  (For completeness the open proxy honeypot should fully log 
the transactions form the spammer-sender.)  Whether the open proxy honeypot 
is being used to contact an open relay or is being used to send the spam 
directly to the victim doesn't matter: either way there is no spam 
delivered.  The Open proxy honeypot need only detect that port 25 is being 
contacted through it and to modify the dialog such that no spam is transmitted.

The long-term ASRG plan may include a replacement or strengthening of the 
SMTP protocol.  What ASRG does need not be limited to a single 
action.  Protocol enhancement may be the key part of the ASRG plan but the 
current intense level of spam calls for immediate action yo substantially 
reduce the amount of spam that reaches all users, as a whole.

What follows was written in response to a message from Paul Judge.  It 
starts by quoting what he suggested should be incorporated in a full 
honeypot proposal.  It isn't all there, but most of it is.  To me the most 
important point is the point made at the start of this posting: ASRG can 
take major action.  Relay spam honeypots, as done, have been of the form of 
minor isolated action.  If you broaden the concept to include action for an 
entire network segment the power of the approach is increased.  While the 
description of honeypots is useful the power, to me, is in the idea of 
taking concerted action to end the abuses committed by spammers to send 
spam.  Whether or not this results in a solution that looks like honeypots 
is unimportant.  What matters is that spam be ended.

Paul's suggestions:
>You should describe the benefits of R.H.
>Describe how to deply one from scratch
>         -who should do it? Large corporations? Individuals? A single
>non-profit?
>Give some metrics.
>         -how much spam will one see
>         -how many are needed to make a difference
>Discuss countermeasures
>Discuss deployment issues
>
>Put this in the form of a document that someone can pick up and read. It
>should convince people to run relay honeypots and show them how to do so. It
>should include all of the ideas that you have thrown around in the different
>emails.

Background:

That spam comes by abuse pathways is well known.  Spammer Alan Ralsky is 
reported to control 190 email servers, including 160 in the US. 
(http://www.freep.com/money/tech/mwend22_20021122.htm) Ralsky does not send 
direct spam - he must therefore send spam via an abuse pathway.  Similarly, 
many other spammers also send abuse spam.

Historically the abuse spam was sent via open relays almost 
exclusively.  Recently these have been supplemented by open proxies and by 
open proxy - open relay combinations.  Open relays are still used, are 
still a problem.  When open relay DNSBL services shut down because they 
have no function it will be known that open relay abuse is no longer a 
significant part of the spam problem.  Similarly, when open proxy DNSBLs 
shut down for a similar reason open proxy abuse will no longer be a 
component of the spam problem.  Neither of these shutdowns seems imminent.

That these spammers use abuse means two things: there is a constant flow of 
abuse packets from their servers and these packets are directed to systems 
vulnerable to abuse that the spammers have discovered.  That they discover 
vulnerable systems means that they look for vulnerable systems.  No doubt 
different spammers have different practices - some may seek abusable 
systems only overseas, some may seek them only in the US, some may do 
both.  Little data has been collected to determine what these practices are 
in general or for particular spammers (or groups of spammers, if 
any.)  Operators who set up relay spam honeypots are generally successful 
in detecting and delivering relay test messages.  Many operators of email 
systems report frequent log entries for rejected relay messages.  The 
evidence is that spammers appear to check for open relays essentially 
everywhere.  If it is necessary to the spammers then the practice creates a 
vulnerability on the part of the spammers.  the intnet is to fully exploit 
that vulnerabilty.

Whether or not the abuse meets the federal standard for action the abuse is 
theft of service.  It is appropriate to report such abuse to the ISP from 
which it originates, it is appropriate for the ISP to terminate service to 
the customer guilty of the abuse.  Surprisingly, some ISPs seem completely 
unaware of the abuse and of its implications.

Honeypots, in this context, are systems set up to appear to the spammer to 
be vulnerable to abuse but not be vulnerable - some key part of the abuse 
is intercepted, usually delivery of spam.  Functions of honeypots vary but 
include detection of the tests done by spammers to discover and verify 
abusable systems and delivering such tests so that the spammer deceives 
himself into believing the tested system is vulnerable.  When the spammer 
so deceives himself he may send relay spam to the system, spam which the 
system makes sure is not delivered.  The basic honeypot is a single system 
with a single IP address.  Those in charge of larger aggregates (e.g., full 
network segments of /24 or larger size) may be able to create giant 
honeypots, in which port 25 (or proxy port) traffic directed to IPs that 
don't service the port is diverted to a master honeypot.

This document will emphasize open relay honeypots.  Similar thinking can 
lead to design and implementation of open proxy honeypots.

An  open relay honeypot can be, broadly speaking, one of two types.  It can 
be a standard MTA configured or altered to make it a honeypot or it can be 
new code, specifically written to function as a honeypot.  The design 
criteria of an ideal honeypot are simple: always look like an open relay to 
the spammer, never deliver spam.  Additional criteria may be chosen that 
define the mode of operation of the honeypot.  It might be designed to be 
fully automatic, for example, or might be partially automatic and partially 
manual.  At the simplest level an open relay honeypot accepts and delivers 
the relay tests sent by spammers.  As the honeypot is supposed to deliver 
no spam and as the act of delivering a spammer relay test usually  leads to 
a spammer sending spam the honeypot needs to have a way to distinguish 
relay tests from spam.   Several approaches have been used.  In one 
approach each new message in the mail queue is examined automatically for 
relay-test-like character.  The easiest  mark of such character is the 
presence, in the message, of the IP address of the honeypot itself - the IP 
address of the open relay is the payload of the test message.  This address 
can either be plaintext (standard dotted quad) or it can be encoded.  A 
very frequently seen encoding is to re-express the IP address in its 
decimal ascii form and to put that before the "@" character in the 
message-ID.  A third form of IP encoding is one in which the periods in the 
dotted quad representation are replaced by slashes and each digit of the 
representation is replaced by the next higher digit.  Thus, 192.168.10.200 
would become 2:3/279/21/311 (the : is what has been observed as the symbol 
for 9 + 1.)  As these addresses always appear with the string MAILINF0 that 
string could be just as appropriate for recognizing relay tests, at least 
before spammers get clever.

A user deploys a honeypot by one of several methods.  If the honeypot is 
based on a standard MTA the honeypot is installed on a compatible system 
that has no MTA but does have a network connection and an ethernet card 
with an IP address.  If there is no such system an older unit may perhaps 
be pressed into service.  Successful honeypots have been based on a 100 MHz 
486 DX4, on a 120 MHz PENTIUM, and on a Vaxstation 4000/90.  The honeypot 
need do nothing compute-intensive - it can be an older system of limited 
capability and still succeed.   If the honeypot is one using 
honeypot-specific software it should be one compatible with the software, 
with nothing else using port 25, and no vital function that is put at 
greater risk by the implementation of the honeypot.  An example of such a 
program is Jackpot: http://jackpot.uk.net/

A very effective honeypot is one that is substituted for an open relay that 
is already being abused.  If the open relay is on a system that has no real 
need for an MTA the existing MTA can be stopped and an appropriate honeypot 
installed and run.  If the system has an email function then its IP number 
might be re-assigned and the honeypot put on a new system that is given the 
IP number taken from the old system.  Regular email follows DNS - spammers 
generally use IP numbers to contact the systems they abuse, so subsituting 
a different system for the one previously at a particular IP does work 
against the spammers.

A relay spam honeypot can be successfully run by anyone connected to a net 
segment the spammers test for open relays.  This appears to include some or 
all IPs in the US, great Britain, Korea, China, Taiwan, Denmark, Germany - 
anyplace the spammers look for open relays is appropriate for a 
honeypot.  This means top-level ISPs can do it, it also means home users 
with DSL or cable connections can do it.  It is important that honeypots be 
run by more than just anti-spammers  The real power of honeypots comes when 
they exist in large numbers - this requires that they be implemented beyond 
the anti-spam community.  Honeypots can be simple enough that this is 
readily possible.

Honeypot users will see varying amounts of spam (if they deliver relay 
tests.)  What they see depends on which spammer or spammers discover and 
decide to use the apparent open relay.  Some spammers will hit a relay with 
a flood of as much spam as they can pump out.  Others send metered 
amounts.  At one time it appeared a volume of around fifty 20-recipient 
messages/day was typical for a honeypot (and an open relay) in the US 
(based on a less-than-representative sample of one.).  Last February the 
Moscow honeypot started working and trapping orders of magnitude more 
spam.  Another foreign honeypot received spam at high levels, with bursts 
of well over 1 million recipients/day for the trapped spam.  (In the first 
year of operation that system stopped spam to 281 million recipients, with 
an average of less than 1 million recipients/day.)  The trapped spam isn't 
all that is important - the relay tests are the problem and the key to the 
action of the honeypot.  The real purpose of honeypots is to disrupt the 
ability of spammers to find open relays.  A natural consequence is that 
most honeypots will also trap spam - that's because they disrupt the 
ability to find open relays by masquerading as open relays.  If they don't 
accept spam the masquerade isn't very good.  Nonetheless the goal is to 
make discovering open relays so difficult that the spammers give up 
trying.  That will lead to the quicker end of relay spam.  (Similarly for 
open proxies.)

While it is a secondary function the spam-stopping power of individual 
honeypots is important, does make a small difference.  Compared to the 
total daily spam volume any small number of honeypots has little real 
impact.  That partly works to the advantage of current honeypot operators: 
if they make no real difference the spammers won't notice that honeypots 
exist.  Stopping spam is a side-effect of the real power of honeypots.  RFC 
2505 says that securing open relays is not an approach to ending spam.  The 
reason is that spammers will continue to discover open relays, so that even 
a 95% success in securing open relays won't stop spam.  The key word is 
discover: the problem is that spammers can discover open relays.  Anyone 
can: try to relay an email message through a million IPs and you'll find 
some that will.  Spammers work the same way: they look for IPs that will 
relay.  When the only relay-level anti-spam countermeasure is to secure 
open relays the spammers see a simple division of systems on the internet: 
those that don't deliver their test messages and aren't open relays, those 
that do deliver their test messages and are open relays.  It's very simple 
for the spammers: if a system delivers a test message it is an open relay 
with near 100% certainty.  That's what makes detection of open relays 
simple for spammers.  The real purpose of honeypots is to disrupt the 
detection of open relays.  It can be regarded this way: as long as 
anti-spammers can build a good list of open relays spammers can do the 
same.  In a way the spammers and the anti-spammers work cooperatively to 
build  a good list of open relays.  Spammers can and have used anti-spammer 
relay lists to find usable open relays to send spam.  Anti-spammers add to 
their lists any open relays discovered by the spammers that become known 
through relay spam reports.

To really disrupt the spammers may take a number of honeypots equal to or 
greater than the number of open relays.  If the numbers were equal then the 
honeypots would be expected to be receiving roughly half the spam, a 50% 
cut in spam volume.  At that level the spammers need only double their 
output to keep the same delivery level.  (Someday the headroom for 
increasing volume will run out - then nothing the spammers can do will keep 
up the volume.)  This analysis neglects the complaints that many honeypot 
operators can send - complaints about attempted theft of service, 
complaints about relay test messages.  These complaints multiply the 
effectiveness of honeypots since they help disrupt the entire spamming 
operation.

While this description is written in terms of open relay honeypots the 
advantage may be with open proxy honeypots: these days an open proxy 
honeypot is more likely to receive a direct connection from a spammer 
(making it possible to track the abuse to its source.)  The design of at 
least one kind of open proxy honeypot is simple: intercept all port 25 
traffic for other IPs and direct it to an SMTP honeypot (integral to the 
open proxy honeypot or external - whatever works.)  Other designs are 
possible.  The important considerations are, as with open relay honeypots, 
that the honeypot deceive the spammer and that the honeypot not deliver spam.

The prime countermeasure a spammer can take is to stop sending spam to the 
honeypot, once he discovers it is a honeypot. In other words, the spammer 
doesn't send spam.  That's the overall goal, for all destination IPs 
(0.0.0.0/0) - the spammer is doing the right thing if he stops sending 
spam.  The real issue would appear to be that of how easily the spammer can 
discover the honeypot.  If the goal is to make discovery of true open 
relays too difficult for the spammer to tolerate then if honeypots are used 
they have to be difficult to detect, have to look very much like true open 
relays.

An isolated honeypot should be easily detected, if the spammer tries.  He 
need only send some spam addressed to his own dropbox and use the fact of 
non-delivery to establish that an IP is a honeypot (other detection schemes 
are possible.)  Creating a situation in which it is necessary for the 
spammer to detect honeypots already has made open relay detection more 
expensive to the spammer, more difficult.  The goal is to increase the 
difficulty until the spammer gives up.  The original deception that got the 
spammer to send spam was to deliver his test message.  The same philosophy 
holds for later test messages, including spam addressed to the spammer's 
own dropbox: if you deliver them the spammer is fooled.  (In the past some 
spammers have sent their standard test message simultaneously with a spam 
run to discover if the relay remains open.  That's trivially easy 
to  handle.)  If the spammer sends spam to his own address then he probably 
will use that same address multiple times.  The honeypot 
counter-countermeasure may be to deposit all spammed addresses in a central 
database, shared by a consortium of honeypot operators.  If the spammer 
uses a test address with any frequency that address will receive 
proportionately more spam than do the ordinary addresses.  Once a test 
address is identified honeypots still working can simply deliver any spam 
that comes for that address, fooling the spammer.

Lower-level honeypots can also be run - ones that only trap relay 
tests.  These, too, will be detectable by the spammer.  If the operator 
believes his honeypot has been detected by the spammer and if he has 
another IP number available he can simply change the IP number and 
continue.  Eventually the spammer will discover that IP, and so on.  The 
goal would be for the spammer to abandon consideration of the entire 
network segment as  having potential abusable open relays.  Note that if 
the spammer regards acceptance of a test without subsequent delivery of the 
test as evidence of a honeypot it is very beneficial for operators of free 
email services used by the spammers for their dropboxes to divert email 
messages to those dropboxes but to leave the accounts active.  This looks 
the same to the spammer as does a failure of the tested IP to deliver.  The 
result could be that the spammer will conclude that an actual open relay is 
a honeypot because the test message was accepted but the spammer never 
received it (just as for the honeypot that accepts but doesn't 
deliver.)  The goal, always, is to disrupt the spammers' ability to test 
accurately.

                                     -o-

Where do honeypots fit in the draft taxonomy 
(<http://www1.ietf.org/mail-archive/working-groups/asrg/current/msg01794.html>)?

In 1. a), as v) Intercept spam

In 1. a), as vi)  Destroy ability to find open relays (open proxies)

In 1. b), under ii, Tracking.

In 2. as c)  If it's trapped by a honeypot and isn't a relay test: it's spam.

In 3) h) Feedback.  Honeypots may discover large numbers of open proxy IPS, 
may discover spammer IPs.

In 3) k)  Teergrubing is possible with a honeypot: Jackpot implements 
it.  Some hackback potential exists: the honeypot may be the spammer's 
first contact point in the spam chain.  The ethics of causing an open proxy 
crash by hackback could be debated - there's some justification for that 
action.

In 3), as l)   Raucous laughter.  You can become very amused at a spammer 
sending copious amounts of spam into a black hole.  It's even more amusing 
if the spammer uses some address "trick," to exploit an address-form 
vulnerability.

Drat, I forgot.  Part of simulating an open relay is simulating a bumbling 
operator.  A honeypot might simulate rejection of standard email addresses 
but simulate vulnerability to one of the other forms of address spammers 
sometimes use.  Similarly, a honeypot can have periods of down time and 
periods in which it responds with a "disk full" message.  I've sometimes 
totally blocked a spam-source IP: a real bumbling operator might do 
that.  The spammer need only change IP to get back in.  Golly, he got me 
again. :-)

Where do honeypots fit in the list of requirements 
(<http://www1.ietf.org/mail-archive/working-groups/asrg/current/msg01721.html>)?

1.  They do reduce the level of unwanted messages.  This would more or less 
be a linear function of the number of active and successful honeypots.
2.  They have nearly zero effect on all valid messages (only extremely 
unlikely situations lead to any disruption at all of valid email 
messages.).  The honeypot might contend for bandwidth with a local 
server.  That should be the full extent of the interference, unless some 
hotshot rogue blocklist somehow learns the honeypot IP and does an expanded 
listing around it.  No such blocklist operator is known to exist.
3.  The honeypot can be easy to use.  For Jackpot you download Jackpot, 
download a JVM, and run Jackpot.  You can configure Jackpot permanently, in 
the jackpot.properties file or you can make configuration changes using 
Jackpot's built-in web interface.  The web interface also allows 
examination of trapped tests and spam.
4.  The honeypot may be easy to deploy.  Jackpot is easy, as described.  A 
sendmail honeypot requires some special configuration.  That's easy, in 
sendmail terms.  Other honeypots could be implemented to be 
easy.  Honeypots could be distributed as an optional package to use with 
anti-virus software or as an optional package with hardware or software 
firewalls. Honeypots could be made part of the standard distribution of 
operating systems (e.g., Linux.)
5.  Honeypots do not depend on universal deployment to be effective - many 
of their features exist and have power at the single-implementation 
level.  To disable the ability to find open relays they will have to be 
widely deployed.  It will probably help tremendously if there are many 
versions and flavors of honeypot.  Much of the power of honeypots depends 
on spammers continuing to search for open relays.  If spammers decide to 
stop searching for open relays and use just the ones they know then the war 
will become one  of attrition, as existing open relays are secured (with 
the best method of securing often being conversion to a honeypot.)
6.  Privacy.  The operator of a honeypot that is successfully trapping spam 
learns the email addresses of the intended victims.
7.  Administration and implementation overhead.   More than one level of 
honeypot can be deployed.  Simple honeypots have minimal requirements.  (If 
honeypots become plentiful then a honeypot that simply accepted relay email 
messages and discarded them would be effective.  The spammers have no way 
of knowing which of such systems are he ones that lead to complaints to the 
spammers' ISPs.  They have to worry just as much about such a low-function 
relay test message trap as they do about a honeypot run by the most active 
anti-spammer. )  Activates based on data collected by the honeypot may take 
time.  Jackpot honeypots can report their activity to a central web server, 
sendmail honeypots could be very simple installations, not honeypots at 
all, and simply smarthost all email to a central master honeypot.  (That 
may carry a somewhat greater risk of spammer discovery but is possiblle.)
8.  Bandwidth is whatever the spammer consumes, as limited by the honeypot 
or by other means. Computational overhead is negligible - it's about like a 
mail server.
9.  Robustness.   Some forms of honeypot are detectable by easy means.  The 
response is to stop testing that IP for being an open relay.
10  Legal issues.  I'd probably die laughing if a spammer sued me for not 
letting him steal my service to send his spam.  If used at all to trigger 
law enforcement there might be an entrapment defense.  Just hooking a 
system to the internet is hard to see as being entrapment.

Who can use these ideas to fight spam?

Anyone who has contact with a resource the spammer uses or abuses in his 
activity.  The spammer's ISP can detect testing for open relays and take 
appropriate measures.  The ISP of the systems being tested can take 
appropriate measures.  The operator of tested systems can take appropriate 
measures.  The operator of a freemail service used by the spammer for his 
dropbox can take appropriate measures.

Conclusion:  This could be a better and more formal proposal but as it is 
it should serve to provide material for consideration and discussion - 
that's the main goal.  There is a long history of people finding fault with 
honeypots simultaneously with real honeypots operating and having 
significant effect.  The proposal is more about fighting spam by fighting 
the abuse committed by spammers to send spam.  The spammers are vulnerable 
to such a defense, such a defense, if pressed vigorously, should greatly 
affect the ability of spammers to continue operating.  That's the 
goal.  Honeypots are already working - their number could be increased at 
any time to increase their overall impact (there's no significant delay 
connected with their adoption - no RFC process that need be 
followed.)  Spam is a huge problem today, honeypots work today.  They need 
to receive careful consideration as a major component of the battle against 
spam.

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---

From: "Jon Kyme" <[email-masked]>
Date: Tue, 15 Apr 2003 14:04:55 +0100

> output to keep the same delivery level.  

Clearly.  What do you think that the trend in the number of open 
proxies / relays is (will be). How long will it take us to have the
neccessary number of honepots deployed?
How expensive is it for spammers to send out duplicate messages?

>This analysis neglects the complaints that many honeypot

But surely entities which receive spam are in as good (or better) position
to
complain (or sue - AOL anyone?) than the operator of what is, after all,
an entrapment device?

> that comes for that address, fooling the spammer.

But if the test address receives no more messages than a regular spam
target address this signature disappears. The spammer just needs a supply
of disposeable addresses.

I can't see how honeypots can have a major impact on the quantity of
unwanted mail
reaching my users unless undetected deployments substantially outnumber
abused relays/proxies. They'd have form a very large majority before they'd
begin to approach
the effectiveness of content-filters surely?

I can see that they might be useful as a research tool - but I can't see
how I could
use your arguments to persuade my boss to let me (fund me to) run one (or a
few)
on our network.

Regards.
Jon Kyme

--

---

From: Brad Spencer <[email-masked]>
Date: Tue, 15 Apr 2003 11:09:02 -0500

>How expensive is it for spammers to send out duplicate messages?

I suspect that open relays are approximately steady-state or slowly 
declining.  I put no great faith in my suspicions nor do I have any 
emotional attachment to them. In any case I don't anticipate any huge 
upsurge in the numbers of true open relays - the spammers surely have found 
99+% of them by now, continue to scan (I assume) because there are enough 
new ones appearing to make scanning worthwhile.

The length of time needed to have enough honeypots to really matter depends 
a lot on the rate at which they are created.  At the present rate it will 
take over 1000 years, probably.  Some of the emphasis in what I posted was 
on the ability of ASRG to influence what people do in a way that would 
speed implementation of whatever ASRG finally did recommend, which could 
include honeypots.  It's impossible to know how many it would take - my 
inclination would be to favor adding honeypots until everybody was saying 
there was no more spam.  If the honeypot is created from an idle old box 
the cost is the cost of the electricity to run it plus the manpower cost of 
setting it up.  That's if spam is dead and there is no traffic for the 
honeypot.  Until then there's also the cost of the network traffic.  If an 
organization feels it can't afford the cost of the network traffic then 
probably it should do at most the absolute bare-bones honeypot: a secure 
MTA that logs relay attempts.

>complain (or sue - AOL anyone?) than the operator of what is, after all,

The concept of entrapment applies only to law-enforcement, and putting a 
system on the net is not an invitation to the spammers to commit 
abuse.  (Entrapment occurs when a law-enforcement agency invites someone to 
commit  a crime and then charges that someone with the crime.   I think the 
discussion of entrapment belongs elsewhere, outside ASRG.  A honeypot is no 
more entrapment than is setting up an email address as a spam trap and 
putting that address on a web page.)

Yes, ISPs and users can complain, but when they do they complain about 
spam.  When a honeypot operator complains he complains about attempted 
theft of service or about relay tests, a prelude to attempted theft of 
service.  Practically speaking the honeypot operator's complaint carries 
more weight.  As far as I know uu.net has acted on every honeypot complaint 
they've gotten, where "acted" means a spammer account was cancelled.  As 
far as I know they have not acted on every spam complaint.  Some ISPs don't 
appear to even know what I'm talking about when I report a relay 
test.  There's clearly not much real understanding of the spam problem in 
the ISP mental space.

>of disposeable addresses.

A huge supply, if there is a huge supply of honeypots and if the honeypots 
share their information.  Plus there are other ploys the spammers can try 
(which I don't particularly want to tell them.)  In  any case it is more 
work than they now must do, since now they can just do their tests and 
trust the results.

>abused relays/proxies.

I can't either.  There are two possible scenarios:

(1) not many honeypots, no major impact
(2) many honeypots, major impact

>  They'd have form a very large majority before they'd
>begin to approach

They work differently from content filters (and blocklists) but yes, they'd 
have to ba a large majority to have a large impact.

A honeypot in the path before a good blocklist or good content filter 
merely grabs the spam first - if the spam was going to be stopped anyway 
the honeypot merely did it sooner.  In front of no blocklist and no filter 
it still grabs the spam.  The honeypot grabs all the spam sent "through" 
it. Blocklists and content filters apparently do not stop all spam.  I can 
envision the ASRG final proposal being strictly one of increased usage of 
blocklists and of content filters.  While those leak and aren't universal 
the honeypots do grab spam that would otherwise be delivered.  The 
honeypots also are an irritant to the spammer in a way the other two are 
not.  I'd say the final proposal should combine several effective 
techniques, with honeypots being one of them.  Honeypots are simpler and 
yet are 100% efficient - a powerful combination.

>use your arguments to persuade my boss to let me (fund me to) run one (or a

Again, trapping spam is a side effect.  The real goal is to make it 
impossible for the spammers to know which systems are and which are not 
open relays or open proxies.  Just as one more honeypot doesn't greatly 
increase spam stoppage one less doesn't greatly decrease spam 
stoppage.  Your boss doesn't have to hear a proposal at all.  If ASRG were 
to recommend honeypots then part of what ASRG would do would be (I think) 
to create a description of what the honeypots are and why they are needed 
sufficiently detailed and sufficiently in "boss language" that many bosses 
would approve.  Better would be for your ISP to tackle the problem of 
spammer abuse - you'd be able to continue what you are doing, your ISP 
would capture the relay and open proxy tests and complain to other ISPs 
about the spammers searching for vulnerable systems to abuse.  All your 
boos need do would be to say how glad he was the ISP was fighting 
abuse.  Your ISP could also simulate a flock of honeypots - pretty soon I 
predict they'd be seeing no abuse traffic at all.  That's the goal, for 
everywhere.  What I really want is for ASRG to focus part of their 
attention on the abuse aspect of spam - that's an area ripe with promise 
for anti-spam activity.  It's so ripe with promise that individuals CAN, if 
they are in the "right" network segment, stop spam to millions of 
recipients with a computer that was obsolete years ago.  Individuals can 
also trap and report relay and open proxy tests, also causing spammers some 
difficulty (if the ISPs wise up.)  The abuse has been almost totally 
ignored up to now.  Combating the abuse is a powerful step forward in the 
fight against spam.

---

From: "Jon Kyme" <[email-masked]>
Date: Tue, 15 Apr 2003 17:57:50 +0100

> Better would be for your ISP to tackle the problem of 
> about the spammers searching for vulnerable systems to abuse.  

What's the incentive to deploy (requirements 4.a ?) for an ISP?