Everyday my directory got around 500 submissions, but around 450 of them are spam submissions. I enabled captcha, but it's not working. Looks like the there are some softwares or scripts which can read the captcha. Most of the links submitted are Russian which come from different IP. Sometimes it's English and from the samep IP, and then I will block that IP. So I want to know what are the softwares and scripts which can read the captcha in my directory submit page. Please list them here, thanks a lot.
I think they are not submitting via form or by reading captcha. If you can change the background of your captcha. Also check out if your site has been hacked. I may be wrong.
Are you sure the captcha is being broken? Captcha-breaking is sometimes outsourced to sweatshop workers. Anyhow, your best bet is to upgrade to version 3 of phpld, the spam controls are better and it will save you a lot of hassle. A trivia question that requires the submitter to read and understand English is one of the most effective protections, so look into that.
I don't want to upgrade to phpld v3 now, since my directory is free and I have budget for that. I only want to know those softwares which can read captcha like botmaster.net.
As I recall correctly, there was a bug in earlier free phpLD versions that allows spammer easy to bypass CAPTCHA. This bus was fixed in latest free version only (I don't know the version number). So, if you don't want to get paid phpld V3, at least upgrade to latest free one.