In recent years Wireless technology iswidely used with the advent of IEEE 802 standard. Lowrate Wireless personal area networks are widely usedbecause of low cost. A mobile ad-hoc network isinfrastructure less network which consist of mobile devices connected wirelesslyand usually move to other places from time totime, move around or join the network. Over the pastyears simulation work has been carried out to achievereliable routing protocol for IEEE 802 standard. The Wireless sensor and ad hoc networks are easily prone to security attacks, once deployed these networks are prone to be attacked and are unprotected. This paper mainly concentrates on various attacks that degrade the network performance. Attacks on the node degrade systemperformance, especially during the route discovery process by malicious entities which results in data loss and slower the network speed. In this paper various security threats will be discussed extensively.

1. Haowen Chan and Adrian Perrig, Security and privacy in sensor networks, Computer 36 , IEEE 2003.
2. Eugene Y. Vasserman and Nicholas Hopper "Vampire Attacks: Draining Life from Wireless Ad Hoc Sensor Networks"- IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 12,NO. 2, FEBRUARY. 2013.
3. Denial of service attacks(Timothy J. Mc Nevin, Jung-Min Park), IEEE 2004 University of Texas at San Antonio, San Antonio, TX 782490667.
4. J. Deng, R. Han, and S. Mishra,"Defending against Path-Based DoS Attacks in Wireless Sensor Networks," Proc. ACM Workshop Security of Ad Hoc and Sensor Networks, IEEE 2005.
5. Aashima, Gagandeep, Pawan Kumar,Analysisof Different Security Attacks in MANETs on Protocol Stack A – Review,International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 –8958, Volume-1,Issue-5, June2012
6. Frank Stajano and Ross Anderson, The resurrecting duckling: security issues for ad-hoc wireless networks, International workshop on Security protocols, IEEE 1999.
7. Rashid Hafeez Khokhar, Md Asri Ngadi & Satria Mandala,A Review of Current Routing Attacks inMobile Ad Hoc Networks,International Journal of Computer Science andSecurity, volume (2) issue (3).

Ad Hoc Networks Attacks Vampire Black Hole protocols