Normally, we would assert that any factory installed software, such as found in /system/app, would not be malicious and could not become malicious unless modified by a user who has rooted their phone.
So with the help of Google, I questioned that assumption and was surprised to find
http://www.cs.cuhk.hk/~cslui/PUBLICATION/ASIACCS2014DROIDRAY.pdf
DroidRay: A Security Evaluation System for Customized Android Firmwares
Min Zheng, Mingshen Sun, John C.S. Lui
Computer Science & Engineering Department
The Chinese University of Hong Kong
It's a scholarly examination of the assumption with a survey of devices and software.
They concluded in no uncertain terms that your phone was shipped with malicious software right from ZTE.
Rooting is the same thing as administrator access on your pc.
If I were you, I would read that article in its entirety, see if you agree with my reading, and if so, see if you can root your phone. If so, you can proceed to freeze the app in question (make it not runable and therefore harmless) and replace it with something else.
You can also begin by checking under settings, Apps, All, find it and see if it will let you disable it without rooting.