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Re: [Asrg] Summary/outline of why the junk button idea is pre-failed
2010-03-02 07:53:05
I'm top posting to give a short answer. Sorry.
I do research on anti-spam filters. Some ideas I investigate are related to
having user feedback, reliable or not. For my requirements, John is right :
I just need two kind of feedbacks : this is ham/wanted or this is spam/unwanted.
This is ok for me.
I may agree with some of your arguments. But OK, you're not interested in
having user feedback. Other people are. So, let they get it. If you think
this is useless, just don't use it. It's an option : MAY, not MUST.
Regards,
JM
Rich Kulawiec wrote:
I'm going to try to summarize and enumerate some of the arguments against
the general idea of a report-as-spam button. My position is that several
of these points (individually) make the case that it's a truly bad idea
and should be abandoned immediately and permanently, and that collectively,
they're an overwhelming rationale. Others differ, of course.
This is a *summary* and not an attempt to provide every nuance
of every argument, so nitpicking is discouraged. You may rest
assured that I read the traffic on this list and have been paying
close attention to the spam problem for the past several decades. ;-)
1. User incompetence
Users have spent the last quarter-century conclusively proving
that they cannot reliably discern spam from non-spam. They stack
the pile of evidence higher every day, by misclassifying spam
as non-spam and vice versa, by replying to spam, by trying to
unsubscribe from spam, by falling for phishes, by handing over
valuable information to spammers, etc. How many "unsubscribe"
requests do we see sent to entire mailing lists, even by
supposedly-mail-literate technical personnel? How many people
on public mailing lists cannot distinguish between on-list and
off-list replies? It's not reasonable to expect that anyone who
has failed to master these rudimentary email tasks will be able
to distinguish spam from non-spam, especially when some spam is
more competently composed and delivered than some non-spam.
This is, I'm sorry to say, not a solvable problem. And it will
steadily get worse as more (less-experienced) people get online,
and as spammers get craftier: evolutionary pressure on spammers
is clearly selecting for the smarter ones.
This can't be avoided by educating users: "educating users"
is one of Marcus Ranum's six dumbest ideas in security for very
good reason. In the case of spam, we KNOW it has failed because
we wouldn't have much of a spam problem to worry about if it
had worked even modestly well.
2. User time
Let's assume that #1 is completely wrong: let's assume that
most/all users are competent spam/non-spam classifying engines.
Let's further assume that they're so proficient at it that they
can do so in 5 seconds per message.
Based on both these incredibly over-optimistic assumptions, we can
then calculate how much end-user time will be spent performing
this classification task and hitting the button. 6.3 million
decisions/pushes equates to about a man-year, which means that even
a single small spam run (say 300 million attempts, 3% delivery rate,
thus 9 million deliveries) can easily chew up well over a man-year
of time. Do the math.
Part of the reason we try to stop spam/spammers is to prevent
them from using up end-user time. We should not be tasking
users with this, as it neatly undercuts part of what we're
trying to do.
3. User exposure
Many clueless users, unfortunately, use web browsers or otherwise
HTML-enabled mail clients to read their mail. (Of course we can
safely presume that competent professional postmasters or abuse
desk personnel don't do this, but the report-as-spam button is
intended for the masses, and they, sadly, do.)
It is certain that in the process of trying to perform classification
tasks, they'll click on links "just to see what's there". This
not only provides very useful information to spammers, but it will
assist phishers, trojan downloaders and others whose goal isn't
really spamming per se, but using spamming to penetrate
systems/networks or perform reconnaissance on them.
4. User influence on security policy
Anti-spam defenses are similar to firewall rules: they control
site security. End-users should not be permitted to override
or otherwise modify firewall settings: neither should they
be permitted to override or otherwise modify anti-spam settings.
First, because it's not their job, second, because they're
not responsible for the consequences, third, because they
lack expertise in this area.
(This is not to say that they shouldn't have input. But all such
input should be manually, carefully reviewed by qualified and very
skeptical personnel before any decisions are made about using it.)
5. Duplicates existing functionality
All competently-run sites support the RFC 2142-stipulated
"abuse" role address and have appropriately experienced,
trained, qualified and diligent staff reading every message
sent there. It's trivially easy for any user to forward
questionable mail traffic (with full headers of course) to
the abuse address of their own mail provider, who can then
decide what to do about it. These personnel are far better
situated to decipher headers, correlate against logs,
assess threat severity, etc. They're also much less likely --
presuming that they're competent -- to hand over useful
information to the enemy. See next point as well.
6. Free useful intelligence for spammers
It's great when your enemy hands you useful information.
It's even better when they expend considerable time and effort to
do so. Spammers can quite easily rig this methodology to provide them
with a wealth of actionable intelligence -- and some of them will.
We should not be building mechanisms that directly support the enemy.
7. Creating more Internet mail traffic is a bad move
We're drowning in (as a more generic term than "spam") junk
SMTP traffic. The last thing we should do is create more of it.
Every possible thing we do to fight spam should dampen the response,
not amplify it.
This (sending outbound traffic) also violates a fundamental
principle of abuse control: do not allow attackers to generate
outbound traffic from *your* site to destinations of
*their* choosing. This never ends well.
8. Report-as-spam button repurposed as weapon
We've already seen how spammers have repurposed any number of
ill-conceived anti-spam concepts (e.g., SAV) as weapons.
They'll do that with this too, should it profit them to do so.
I trust at least a few methods are obvious on inspection;
there's also a few non-obvious ones that I will not be discussing
on a public mailing list, some of which relate to the next point.
9. The zombie problem
There are, at bare minimum, 100 million fully-0wned systems
out there. I've seen estimates as high as 250M (Cerf) and more
moderately, 140M (Kletnieks). My back-of-the-envelope
estimate is currently 200M. And climbing.
It doesn't really matter. Whatever the number is, it's enormous,
and growing steadily. And abusers who now own those systems *also*
own every report-as-spam button that those users have access to,
e.g., if they have a work email account, home email account,
freemail account, then they fully control all three. They can
suppress pushes; they can create pushes. They can generate
ersatz traffic in order to suppress or create pushes related
to it. They can manipulate this any way, every way, they wish.
They can create additional email accounts -- at their own ISP
(many consumer ISPs offer 5 per household and similar) or at
freemail providers just to have more buttons to push more often.
Or *not* to push, which is just as important.
Moreover, they can do this easily and cheaply, and far faster
than real live users can. And they can do it in much greater
numbers -- surely it is extremely unrealistic to expect all
users, or a majority of users, to use such a button,
even if furnished to them.
Which means that spammers can easily dominate the statistics by
as much as they wish. They could, on a whim, account for 10% or 50%
or 90% or 99% of them. Of course, *today* there is little reason
for them to bother. But if we (again, very over-optimistically)
presume that a report-as-spam mechanism is deployed tomorrow
without any of the *other* issues listed above, THEN they will
have a reason to. Spammers have long since proven that they can
and will innovate when they need to -- and quickly.
Summary of the summary:
I think any of 1, 6, 7, 8, and 9 alone are sufficient to kill the
idea outright. 9 kills a lot of ideas outright: it's the elephant
in the room that lots of people like to ignore or wishful-think away
because it neatly undercuts what they're proposing. 6 is often
badly under-estimated by those who haven't put in the time required
to study the enemy.
I think 2 and 3 are strong points but not sufficient to kill it.
I think 4 is arguable, but sites which allow users to override system
and network administrators tend to show up on the dataloss mailing
list and similar. It's a very bad move to allow users to make any
decision related to security: they will invariably choose poorly.
(e.g., Knight-in-cave-after-bad-guy-dies-horribly: "He chose...poorly".
Yeah. Like that.)
We've had 5 for years; what we unfortunately don't have are sites
that operate their abuse desks properly. A button is not a substitute
for diligent staff who are willing to individually investigate every
single abuse report. This is called "baseline competence" and it's quite
reasonable to expect it of every operation, regardless of size.
Could *some* of these be mitigated? Yes. Rate-limiting, DNS bogusing,
firewalling, and other mechanisms might be able to at least slow down some
of the resulting attacks and abuse. (For example, DNS bogusing can be
used to prevent users on intranets from resolving the hostnames of
known-phishing sites, thus probably preventing them from accessing their
web sites. Of course this won't work for users who are reading their
work email from home and using their ISP's resolvers.) But there's no
fixing 1, 2, 6, 8 or 9.
Bottom line: widescale deployment of this builds a mechanism that spammers
will own the moment they choose to do so. I can't say for certain what
they'll choose to do with it, but it would be silly to think that whatever
they do with their brand-new toy will be for *our* benefit.
---Rsk
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