Monday, October 13, 2003


Low-tech Anti-Comment Spam for Blosxom Writebacks


I’ve had an increasingly annoying problem with comment spam in the writebacks for some of my older entries. The usual suspects have devised semi-automatic comment spamming scripts that look for blogging-related entries via Google and serially spam comment-enabled weblogs with links to the expected sorts of things. Most of the discussion I’ve seen online about preventing this has been geared towards Movable Type-hosted blogs. Noticing that most of the comment spam happens in older entries that probably aren’t going to see any legitimate new comments, a lot of folks simply close discussion on older entries after a few weeks, which I think is natively supported in MT.

Closing comments for a Blosxom entry is pretty simple, as well: just make the writeback entry read only. On Unix platforms, just change the mode of the writeback (.wb) file to 444. I don’t know the Windows equivalent, but I’m sure it’s just as simple. If someone (usually a spammer) tries to post a writeback to one of your old entries, they get (at least in the default writeback setup) the message: “There was a problem posting your writeback.”, which is fine for my setup, though I suppose it’s easy enough to customize the message if you like.

I imagine it would be about a 3 line perl script to simply walk your writebacks file tree and close all extant writebacks older than a certain number of days, but I’m a little too lazy to do that today.

edit: Blosxom folks: there’s a blacklist plugin here.
MT People: there’s a blacklist plugin here.


:: Dave Walker 14:40 (EST/EDT) [+]

:: [/tech/computers/blosxom]
:: tags:

:: Comments (3)

Comments:

Quarter Life Crisis wrote:

Title: Notes

Date:

Response:
Nick Hornby's Desert Island discs and him cheating by using an iPod (via 2lmc). I do wonder, though, why no-one pointed to Hornby's 31 Songs on the way. Seems...
Rev. George wrote:

Title:

Date:

Response:
It seems like you could use find to do the same thing. The only problem is that find uses the mtime so you would need to identify old posts that have recent comments somehow... This is how you would close all comments:
find /path/to/your/writebacks -name '*.wb' -exec chmod 444 {} \;
Doug Alcorn wrote:

Title: Keyword Based Blacklisting

Date:

Response:
I saw all the stuff on the MT-Blacklist and "ported" the concepts over to blosxom. In fact, I use the same blacklist they do for preventing comments from known spammers. I've also written a little utility for cleaning up comment spam based on keywords while leaving the other writebacks intact. This means you don't have to "close" old blog entries unless you really want to.



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