The name is based on admittedly weak evidence. According to the Russian Wikipedia page on Mal (knyaz):

http://ru.wikipedia.org/wiki/%D0%9C%D0%B0%D0%BB_(%D0%BA%D0%BD%D1%8F%D0%B7%D1%8C)

In English:

Possible kinship

According to Vasily Tatischev, in the Ioachimskoy Chronicle [1], Mal is said to be "Prince Drevlian, son of Niskinin.

Some historians believe that Mal's children could be Malusha (the housekeeper of Princess Olga and mother of Prince Vladimir), and Dobrynya. They occupied positions in the court household of Olga and Svyatoslav, but failed to reach any considerable height in public administration.

Dobrynya became governor of Novgorod, where he was soon sent with Vladimir and Malusha. The Chronicle calls the father of Malusha "Malk Lyubchanin". In epics, Dobrynya has a patronym of Nikitich, and is reputed to be a "country bumpkin." Given that Mal in some chronicles is called "Niskinya," as suggested by the patronym Nikitich, has provided some late rethinking of the patronym Niskinich.

Barn:
Mal Prince of the Drevlians, född cirka 860