Spam attack through wp-login.php?action=register

On the 15th of May my girlfriend started complaining abut the number of new users with suspicious data that have registered on her blog. Looking at the Apache logs:

111.94.XXX.XXX – – [15/May/2011:07:48:57 +0200] “POST /wp-login.php?action=register HTTP/1.1″ 200 2857 “http://www.domain.com/wp-login.php?action=register” “Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 GTB6 (.NET CLR 3.5.30729)”

I found out, that all visits came from different IPs and didn’t have the referral specified.

The captcha under the registration form didn’t seem to stop the spammers. I had to find the quick fix, until the registration stops and spam starts to roll in. The closest solution I found was four years old, so I had to do a little update with the help of Apache documentation.

# Disable spammy registrations
RewriteCond %{REQUEST_URI} “^/wp-login.php$” [NC]
RewriteCond %{QUERY_STRING} “action=register” [NC]
RewriteCond %{HTTP_REFERER} “!^http://([^.]+.)?domain.com/.*$”
RewriteRule (.*) “/wp-login.php?” [L,R]

What that means is: if a user doesn’t visit “/wp-login.php?action=register” through clicking on a link on “domain.com”, he will be redirected to “/wp-login.php”.

Update: And don’t forget to delete the spammy users form the database. Backup your data and run select, before you use the delete query. I executed this through phpMyAdmin:

DELETE u, um
— SELECT distinct u.*
FROM wp_users u
left join wp_usermeta um on um.user_id = u.id
WHERE u.id between X and Y
— and u.id not in (‘A’, ‘B’, ‘C’)

To get the numbers for X and Y, use Browse on ‘wp_users’ table to get the first and the last unwanted registration. If you find a legit user (A, B, C, etc.) in this range, exclude it with appropriate filter.

  1. I have the same problem.Tank you.

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