Blocking a distributed, consistent spam attack? Could it be something more serious?

Posted by mattmcmanus on Server Fault See other posts from Server Fault or by mattmcmanus
Published on 2010-03-28T19:52:44Z Indexed on 2010/03/28 19:53 UTC
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I will do my best to try and explain this as it's strange and confusing to me. I posted a little while ago about a sustained spike in mysql queries on a VPS I had recently setup. It turned out to be a single post on a site I was developmenting. The post had over 30,000 spam comments! Since the site was one I was slowly building I hadn't configured the anti-spam comment software yet.

I've since deleted the particular post which has given the server a break but the post's url keeps on getting hit. The frustrating thing is every hit is from a different IP. How do I even start to block/prevent this? Is this even something I need to worry about?

Here are some more specific details about my setup, just to give some context:

  • Ubuntu 8.10 server with ufw setup
  • The site I'm building is in Drupal which now has Mollom setup for spam control. It wasn't configured before.
  • The requests happen inconsistently. Sometimes it's every couple seconds and other times it's a an or so between hits. However it's been going on pretty much constantly like that for over a week.

Here is a sample of my apache access log from the last 15 minutes just for the page in question:

dev.domain-name.com:80 97.87.97.169 - - [28/Mar/2010:06:47:40 +0000] "POST http://dev.domain-name.com/comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 202.149.24.193 - - [28/Mar/2010:06:50:37 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 193.106.92.77 - - [28/Mar/2010:06:50:39 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 194.85.136.187 - - [28/Mar/2010:06:52:03 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 220.255.7.13 - - [28/Mar/2010:06:52:14 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 195.70.55.151 - - [28/Mar/2010:06:53:41 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 71.91.4.31 - - [28/Mar/2010:06:56:07 +0000] "POST http://dev.domain-name.com/comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 98.209.203.170 - - [28/Mar/2010:06:56:10 +0000] "POST http://dev.domain-name.com/comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 24.255.137.159 - - [28/Mar/2010:06:56:19 +0000] "POST http://dev.domain-name.com/comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 77.242.20.18 - - [28/Mar/2010:07:00:15 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 94.75.215.42 - - [28/Mar/2010:07:01:34 +0000] "POST /comment/reply/3 HTTP/1.0" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 89.115.2.128 - - [28/Mar/2010:07:03:20 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 75.65.230.252 - - [28/Mar/2010:07:05:05 +0000] "POST http://dev.domain-name.com/comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 206.251.255.61 - - [28/Mar/2010:07:06:46 +0000] "POST /comment/reply/3 HTTP/1.0" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"
dev.domain-name.com:80 213.194.120.14 - - [28/Mar/2010:07:07:22 +0000] "POST /comment/reply/3 HTTP/1.1" 404 5895 "http://dev.domain-name.com/blog/2009/11/23/another" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"

I understand this is an open ended question, but any help or insight you could give would be much appreciated.

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