sycophant /sĭk′ə-fənt, sī′kə-/ noun

A person who attempts to gain advantage by flattering influential people or behaving in a servile manner. A tale-bearer or informer in general. A parasite; a mean flatterer; especially, a flatterer of princes and great men. 

The American Heritage® Dictionary of the English Language, 5th Edition

https://en.wiktionary.org/wiki/sycophant

In this case, either:

One who uses obsequious compliments to gain self-serving favour or advantage from another; a servile flatterer

or

One who seeks to gain through the powerful and influential