Image verification(captcha) on Login*Urgent

[parash]

I am currently using 3.7.4 version of vbulletin , In some days i noticed users accounts are being hacked...i tried to search image verification or captcha system while loging in the user accounts on board.
Is there any supportable addon for this 3.7.4 version ...or we can add that manually while logging in...If yes then How is it possible ?

Thanks.

--------------- Added [DATE]1229212210[/DATE] at [TIME]1229212210[/TIME] ---------------

Originally Posted by parash

I am currently using 3.7.4 version of vbulletin , In some days i noticed users accounts are being hacked...i tried to search image verification or captcha system while loging in the user accounts on board.
Is there any supportable addon for this 3.7.4 version ...or we can add that manually while logging in...If yes then How is it possible ?

Thanks.

Anyone ?