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Blog software upgrade helped with comment spam

Posted: 2013-09-30 18:41:00, Categories: General, Free software, 487 words (permalink)

I recently upgraded the software of my blog to the most recent version of b2evolution. The main reason was simply to stay current with security and bug fixes. Another reason was the new "mass delete" option to get quickly rid of comment spam. As a nice surprise, most of the daily load of spam disappeared without even needing to go through and remove it.

My blog doesn't have a large number of followers, who would regularly comment on the articles. Over 90% of the comments have already for a long time been spam, senseless junk messages trying to advertise some product. I haven't really understood why the spammers have been so persistent: the comments are moderated which means that their message never gets out to the public anyway. Besides, a Captcha plugin at the bottom of the comment form is at least attempting to make sure that commenters are humans and not spam generating robots. I'm not using the centralized blacklist of b2evolution, because I don't want to block domains or content based on keywords, at least if I haven't selected the blocking criteria myself.

In any case, by summer 2013 the situation had gotten pretty bad. The blog was collecting more than a thousand spam comments per month, the traffic of my website exceeded 10GB/month, and over 70% of hits were coming from China. That sounded strange: my site has no content about China or in Chinese language. A couple of Chinese sites link to a few of my photos, but that didn't explain the big mass of visits. Logs showed that most of the traffic was requesting articles from the blog and posting comments on them.

After the upgrade, the number of spam comments dropped immediately to about one per day. The share of hits coming from China dropped to less than half of the total, although it's still surprisingly high at 40%. When looking at the amount of transferred data, connections from United States are leading with about 30% of total, Chinese traffic is less than 10%. Before the upgrade, the amount of traffic from China was equal to that from the U.S.. Finland comes as number three, but far behind the top two. That sounds reasonable — as I write in English it's not a big surprise to have more visitors from U.S. than from Finland.

The most likely conclusion coming to my mind is that the old version of the software had a bug, allowing comments to be posted by automated scripts without going through the Captcha. Although I didn't change the Captcha plugin itself, now it seems again to keep most of the spam out. Or the scripts used by spammers simply aren't upgraded yet to match the new b2evo. Whatever the reason, let's hope it stays like this at least for a while.

Non-spam comments are welcome. :-) Particularly, if you notice something has been broken due to the upgrade, I'd be happy to hear about it.

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