Senkou no Whiteout

Matsuyuki Sakura, a boy who looks as pretty as any girl, becomes a “magical girl” to fights against a malicious virus that is lurking in a huge server.
Matsuyuki is asked to help Shiori Himuro, the “Gospel of Darkness,” the ace of magical girls, but Shiori finds out that Matsuyuki is a man and calls him a disgusting pervert.
In the meantime, the two are attacked by the “Queen,” the source of the virus. He needs the cheering comments from online spectators, but if they find out he's a boy, it will surely be the doom of his social life.

This is a magical girl battle comedy in which a boy fights alongside the heroine. At the same time, he must also protect the content of under his skirt.

(Source: Pony Canyon Books, translated)