无孔不入wú kǒng bù rù

没有什么孔隙不钻入的。比喻消极的东西易于渗透、侵入。亦指人善于钻营，有隙就乘机营求。

英(of odours,ideas,etc.)be all-pervasive; make one's way into every nook and coners; seize every opportunity to do evil;