Mobile Ad-hoc NETworks (MANETs) are exceedingly vulnerable as there is no trustworthy central authority and fixed topology. Moreover, several nodes act as same time in MANET and communication is hop by hop using in-between node. Due to a reason numerous different kind of attacks are probable on network. In this paper, the authors can explain various kind of attack that affected on mobile ad-hoc network. There are basic three kinds of attacks in nature like basis of nature, basis of location, and basis of protocol stack.