Mailman-Developers August 2009

mailman-developers@python.org

24 participants
12 discussions

Proposed: remove address-obfuscation code from Mailman 3

by Rich Kulawiec

Summary: Spammers now have so many ways of "harvesting" addresses from so many systems, and so many ways of exchanging those with each other, that any email address which is actually used WILL eventually be harvested. (Where what "eventually" means varies widely, of course, but can be expected to steadily decrease.) Pretending that address obfuscation in mailing list [or newsgroup] archives will have any meaningful effect on this process gives users a false sense of security and has zero anti-spam value. Summary of summary: It's pointless. Explanation: Spammers maintain extensive databases of email addresses. Some of those databases are merely lists of addresses; others are more sophisticated and include data such as "harvested-date", "havesting-method", "last-seen date", "last-seen-context", "last-known-valid date" and more. Some of these databases are private; others are available for sale/lease. Some are maintained by spammers themselves, others by spammer support services don't directly engage in spamming. The harvesting engines used to acquire email addresses are myriad, as are the methods by which spammers acquire the raw data to use as input to them. *Some* of those methods, and there are many more, include: - subscribing to mailing lists - acquiring Usenet news (NNTP) feeds - querying mail servers - acquiring corporate email directories - insecure LDAP servers - insecure AD servers - use of backscatter/outscatter - use of auto-responders - use of mailing list mechanisms - use of abusive "callback" mechanisms - dictionary attacks - construction of plausible addresses (e.g. "firstname.lastname") - purchase of addresses in bulk on the open market. - purchase of addresses from vendors, web sites, etc. - purchase of addresses from registrars, ISPs, web hosts, etc. - domain registration (some registrars ARE spammers) [1] - misplaced/lost/sold media (hard disk, tape, CD, DVD, USB stick, etc.) and perhaps most significantly: - harvesting of the mail, address books and any other files present on any of the hundreds of millions of compromised Windows systems [2] Consider for example: the first time a newly-created address is used by someone (who is sending a message to it), it's now present on their system: in their saved outbound mail, or perhaps in their address book (if they have one), or in some cache. Any sensible malware resident on their system will of course pick it up and eventually hand it over to a harvesting agent. (Competent malware will harvest it in real time *and* associate it with the sender's address.) And if that particular system happens to be clean? Doesn't help much, because the more times that address is used, the more systems it's present on. And the more systems it's present on, the greater the probability that one of them is already compromised or will be soon. Thus even if we eliminate the originating end-user system as a possible source, we still have to consider the outbound mail server used by that end-user system, which is also a candidate for compromise. And then the inbound mail server used by the recipient, and then the recipient end-user system. And if there's some filtering appliance or intermediate system in place at either end, then it's there too. If the message is forwarded to a third party, then another set of systems is in play. If mail server logs are rolled up and moved to some central location, then it's there too. If backups are made, then it's present there, and subsequently may be present on any system where the backups are read/restored. And finally, if the destination of a mail message isn't an individual user, but an entire mailing list, then we must multiply the number of possible harvesting points by at least the number of people on the mailing list plus a factor for mail servers/gateways/filters/etc. (modulo overlaps). This in turns means that messages to sent to lists of any appreciable size (say, 1000 members) will turn up on considerably more than 1000 systems -- and the chances that all 1000-plus are secure are microscopic. Please note that the previous paragraph's recitation only covered the last vector I enumerated in the [indented] list above: compromised systems. That laundry list of methods also affords many other opportunities for addresses to find their way into spammers' hands. As just one pointed example out of a great many more that could be cited: how do you know that the address user(a)example.com which has just subscribed to the list you run is a real person and not just the front-end for an address-harvester that will pick up every address used to send traffic to the list? And so on. There are far too many others to enumerate, all of which have discussed at great length in anti-spam forums for many years, and are depressingly familiar to experienced practitioners working in the field. The bottom line is that any email address which is actually used [3], *especially* any email address used to send traffic to a mailing list, is going to be harvested. It's only a matter of when, not if, and "when" is getting sooner all the time. Incidentally, everyone (including me) can produce anecdotal tales of addresses that have remained surprisingly under-targeted by spammers over long periods of time. But this is clearly not the way to bet: it is in spammers' interests to ferret out as many addresses as possible and to use them as soon and as often as possible. Note, however, that some addresses are *deliberately* un-/under-targeted, so lack of substantial spam traffic to a given address is NOT an indicator that the address hasn't been harvested. That's because along with target lists, spammers maintain "suppression" lists, which they use to avoid hitting the addresses of people they think are likely to cause issues for them. [4] And obviously, people with postmaster or mailing list roles would be good candidates for membership on those lists. I know that if I were in their shoes, I'd add everyone who's ever sent a message to the mailman-* mailing lists to mine: a quick check indicates that it's on the order of only 10K addresses. Skipping those would be inconsequential when sending spam to a few hundred million addresses, and I trust it's obvious why spammers would benefit from doing so. With all this in mind, it's clearly pointless to pretend that address obfuscation in archives provides any protection at all. [5] It would be better to remove the code entirely than to continue to maintain the facade that it actually has any anti-spam value. Everyone should simply presume that all email addresses are in the hands of spammers and prepare defenses accordingly -- because even if that's not quite true yet, it will be soon enough. Notes: [1] I deliberately didn't mention mass WHOIS queries. While some efforts in this direction were made by spammers years ago, they've found it far more efficient and cost-effective to simply buy WHOIS data in bulk. There's always someone who wants to sell, and a CD/DVD or USB stick will suffice. This is why attempts by registrars to rate-limit queries or restrict access are not only foolish, but disengenuous: spammers already *have* the data, and can acquire updates at will, and they are clearly doing so via processes that lead back to registrars themselves. [2] The exact number of such systems is not only unknown, but unknowable, since any compromised system which (a) doesn't make its presence known (b) to a suitable detector will remain undetected indefinitely. However, two things are clear: (1) any estimate under 100 million should be laughed out of the room, and (2) there is no reason to suspect that the number is decreasing, and there are numerous reasons to suspect that it's increasing. Note, incidentally, that some detectors have reported observing 200,000 new such systems in a single day; and further note that it's now quite routine for individual botnets with several million *known* members to turn up. [3] Addresses which aren't used may remain out of spammer view for considerable time, depending on the care with which they're selected and maintained. However, this obviously excludes addresses used for participation in mailing lists. [4] For the purpose of this discussion, I'm just talking about suppression lists which enumerate individual email addresses. It's well-known that spammers also maintain suppression lists of MX's, domains, network allocations, ASNs, etc., in an attempt to avoid hitting spamtraps and/or hitting the mailboxes of those who might be in a position to file complaints or take action against them. [5] The only people left who are impeded in the slightest by obfuscation code are NON-spammers: that is, people who are trying to contact someone who has previously sent a message to some mailing list. ---Rsk

12 years, 1 month

Looking for a mailman developer to hire

by John Goodell

Am looking for an experienced mailman developer to hire for a few small installations/upgrade to our deployment, including: personalized header/footer fields (using qmail injection), attachment issue for HTML messages, and a few others. Thanks, John

12 years, 3 months

Re: [Mailman-Developers] Proposed: remove address-obfuscation code fromMailman 3

by Ian Eiloart

--On 24 August 2009 13:15:03 -0500 "Hopkins, Justin" <hopkinsju(a)umsystem.edu> wrote: > Thanks for such a detailed and compelling post..but I must disagree. I > can't refute any of the arguments you made, they are all quite sound, but > I do take issue with your conclusion. > > Obfuscating the email addresses is just a part of 'defense in depth' - > same as patching your computer, using a firewall, etc. Each layer, no > matter how thin, still adds something. > > Cheers, > Justin Quite right. Rich's argument is, essentially, that obfuscation isn't 100% effective so it shouldn't be used. Frankly, if it's 10% effective, then it's worth doing in my view. Further, Rich offers no evidence of significant harm done by obfuscation. Finally, there are other privacy concerns than spam harvesting that may also be mitigated by address obfuscation. -- Ian Eiloart IT Services, University of Sussex 01273-873148 x3148 For new support requests, see http://www.sussex.ac.uk/its/help/

12 years, 4 months

Sysadmin/Mailman gig

by Barry Warsaw

A friend of mine forwarded this sysadmin/mailman gig announcement to me. Apparently the Mailman component is fairly high priority. If you're interested, please respond directly to them -- I have no connection to or vested interest in Dreamfish. http://network.dreamfish.com/wiki/Lead_Systems_Administrator_-_Dreamfish_Se… -Barry

12 years, 5 months

Re: [Mailman-Developers] Proposed: remove address-obfuscation code fromMailman 3

by Stephen J. Turnbull

Justin Hopkins writes: > Obfuscating the email addresses is just a part of 'defense in > depth' - same as patching your computer, using a firewall, > etc. Each layer, no matter how thin, still adds something. That's true. Rich's argument is more subtle than a claim that obfuscation is worth nothing, though. It is that benefits to obfuscation are small, and the cost is significantly larger than the benefit. You have to address the issue of the cost (obfuscating the address obstructs legitimate third-party users) as well. Note that the other strategies you mention -- patches, firewalls, etc -- do not impose costs on third parties, only on you. Personally, I subscribe to Rich's argument. I do not obfuscate my own addresses, and I argue against it when I have input into policy for processes like archiving mailing list posts. But Mailman needs to serve people who have different cost/benefit tradeoffs than Rich and I do -- I agree with you and Bernd that Mailman should provide the facility (though I would advise against relying on it, and generally deprecate its use, myself).

12 years, 5 months

RELEASED GNU Mailman 3.0 alpha 3 (Working Man)

by Barry Warsaw

I am happy to announce the release of the third alpha version of Mailman 3, code named "Working Man". This is primarily a preview release so that developers and other interested people can download the code and participate in Mailman 3's further development. I believe we are on track for a final release by the end of the year, and your contributions of code, feedback, documentation, etc. will be welcome and appreciated! Please note that this is an alpha release and as such is not ready for production use. You can get the code from the Cheeseshop: http://pypi.python.org/pypi/mailman/3.0.0a3 Mailman 3 is buildout based and requires Python 2.6. To build it, run this after unpacking the tarball and cd'ing into it % python bootstrap.py % bin/buildout From there you can run the tests % bin/test and build the documentation % bin/docs Highlights in this release include the start of a REST admin server for integrating Mailman with external web sites, a combined bin/ mailman uber-command, configuration now done through ini-files using lazr.config, and better LMTP support. Enjoy, -Barry

12 years, 5 months

Getting code in? (was: Storm based MemberAdaptor for Mailman)

by Andrew Grover

On Sat, Aug 8, 2009 at 1:25 AM, Malveeka Tewari<malveeka(a)gmail.com> wrote: > I am working on writing a storm based member adaptor for mailman so that the > mailman membership data can be stored in a database instead of .pck files. > The reason for choosing storm is that it provides an abstraction to use any > underlying db language- either mysql, postgresql or sqllite. Hi, I'm one of the GSOC mentors for Systers, all of whose students are working on Mailman enhancements. Some of these (Like Malveeka's) would be suitable for merging upstream, but the review and acceptance process is not clear. * Do people on this list regularly provide review of proposed enhancement patches? * Is there a set of people who explicitly ACK or NAK all proposed patches? * Once reviewed, merging is via LP merge requests, right? Or does one do the merge request and *then* get reviewed? * More fundamentally, is Mailman currently accepting patches from external contributors? We have code to contribute. It's not perfect yet but we will make it better. We need some Official Mailman participation or our improvements will never make it out of our branch. Even a response of "we're not interested in X, thanks" would be much superior to no response at all. Thanks -- Regards -- Andy

12 years, 5 months

Re: [Mailman-Developers] Searchable archives for MM

by Siggy Brentrup

Args, I knew I forgot sth, I should have selected MIME digest :) On Thu, Aug 06, 2009 at 22:19:30 -0700, Jordan Hayes wrote: > Here's my solution: > > http://infothecary.org/jordan/mailman.html Nice solution Jordan, but I think about a pythonic way to fully integrate searchable archives into MM. I was using the debian archive search only as an example for what can be achieved on big archives. Thanks Siggy -- bsb-at-psycho-dot-informationsanarchistik-dot-de or: bsb-at-psycho-dot-i21k-dot-de O< ascii ribbon campaign - stop html mail - www.asciiribbon.org

12 years, 5 months

Storm based MemberAdaptor for Mailman

by Malveeka Tewari

Hi all I am working on writing a storm based member adaptor for mailman so that the mailman membership data can be stored in a database instead of .pck files. The reason for choosing storm is that it provides an abstraction to use any underlying db language- either mysql, postgresql or sqllite. I have created a branch on launchpad for this adaptor and would be great if I can get a code review of the adaptor ,t he schema of the db that I am using for storing memberships data and an opinion of whether such a member adaptor is desired at all. Presently the storm adaptor is written for Postgresql but it will support mysql and sqllite with slight modifications. Please take a look at *Mailman/PgsqlMemberships.py* at * https://code.launchpad.net/~malveeka/+junk/StormMemberAdaptor* under the first revision. The work is under progress and for now, I using to storm to create a database with memberships data alongwith the pickle files. The Mailman/PgsqlMemberships.py subclasses OldStyleMemberships.py and still uses the accessor methods in OldStyleMemberships instead of accessing the data from the postgres db. The ideal case would be to use only a database and no pickle files for Memberships data but I have not reached there. I had tried to read and use the data from the database instead of pickle files and that had broken my Mailman which leaves me with few questions In OldStyleMemberships.py the lower cased email address is used as a key for accessing the membership properties. However in my schema, I am using the (listname, case preserved email address) as the PK. Is it possible that not storing and using LCE as a key might break something. I also want to make sure that in the database I am caturing all the Memberships data. Presently my database uses the following class as a storm abstraction for the database. Do I need to add/remove anything? class PgsqlMembers(object): __storm_table__ = "mailman_test" __storm_primary__ = "listname","address" listname = Unicode() address = Unicode() password = Unicode() lang = Unicode() name = Unicode() digest = Unicode() delivery_status = Int() user_options = Int() topics_userinterest = Unicode() bounce_info = Unicode() delivery_status_timestamp = Unicode() Looking forward to your reviews and finally getting the thing in place!! Thanks a lot all Malveeka

12 years, 5 months

Re: [Mailman-Developers] [Mailman-Users] mailman user password

by Adam McGreggor

*shimmied over to mailman-devs* (from -users) On Fri, Aug 07, 2009 at 10:33:06AM -0400, Barry Warsaw wrote: > It kind of sucks that there are so many other Mailman command line > scripts, which is one reason why I've always put them in a separate > Mailman specific bin directory. With MM3 though I intend to use a > 'subcommand' approach so that there's only one 'mailman' command. > Think things like 'mailman listmembers foo'. I'll probably keep > mailmanctl separate though I haven't decided about that yet. Would it too much to ask for the 'old' (read 'current') scripts/commands to be aliased: at least in the first few releases? e.g., for 'list_members' to link to 'mailman listmembers' Perhaps as an install/configure/compilation option? "Create old-style links?" --old-style-links (maybe that's more for people who package: ISTR a couple of packagers are on list, yes?) (wonders how many other people have scripts that would need re-writing otherwise...)

12 years, 5 months

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Mailman-Developers August 2009