无意中发现网站被收录了一些空链接，如何才能将这些空链接指向404页面，哪位高手请指点一下，万分感谢！

这些空链接的规律如下：

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/forum.php?mod=-2267)%20UNION%20ALL%20SELECT%203588%2C%203588--%20
/forum.php?mod=-2267)%20UNION%20ALL%20SELECT%203588%2C%203588--%20
/forum.php?mod=-2321
/forum.php?mod=-2321
/forum.php?mod=-2321
/forum.php?mod=252647
/forum.php?mod=-2575
/forum.php?mod=-2575
/forum.php?mod=-2643
/forum.php?mod=-3148
/forum.php?mod=-3148
/forum.php?mod=-3298
/forum.php?mod=-3357%27%20UNION%20ALL%20SELECT%205048%2C%205048%2C%205048%23
/forum.php?mod=-3357%27%20UNION%20ALL%20SELECT%205048%2C%205048%2C%205048%23
/forum.php?mod=-3357%27%20UNION%20ALL%20SELECT%205048%2C%205048%2C%205048%23
/forum.php?mod=-3419
/forum.php?mod=-3419
/forum.php?mod=-3588
/forum.php?mod=-3588
/forum.php?mod=-3664
/forum.php?mod=-3664
/forum.php?mod=-3695
/forum.php?mod=-3698%20UNION%20ALL%20SELECT%207458%2C%207458%23
/forum.php?mod=-3750%25%27%20UNION%20ALL%20SELECT%209808%2C%209808%23
/forum.php?mod=-3783
/forum.php?mod=-3783
/forum.php?mod=-3843
/forum.php?mod=-4071%20UNION%20ALL%20SELECT%201807%2C%201807%2C%201807%23
/forum.php?mod=-4071%20UNION%20ALL%20SELECT%201807%2C%201807%2C%201807%23
/forum.php?mod=-4071%20UNION%20ALL%20SELECT%201807%2C%201807%2C%201807%23