Security and anonymity are important issues for mobile ad hoc network (MANET) routing protocols especially in hostile environments. The adversary nodes can launch traffic analysis against routing information embedded in routing messages and data packets. In this paper we analyze the limitations of the several existing anonymous routing protocols, then we propose a new efficient anonymous on-demand routing protocol which is called MASR (MANET anonymous secure routing). It is inspired by a combination of DSR, TOR, ANODR and AnonDSR and can overcome the limitations of current anonymous routing protocols. Through analysis and simulation, we demonstrate that MASR has comparable performance with the AODV and DSR routing protocols and also has strong anonymity and security protection.