It was the second two-goal game of the season for Aubert, who also assisted on Keast's score to set a new career-high with five points.
Aubert's first goal was assisted by junior Alen Hataric at 26:46 and the score remained 1-0 for the rest of the opening half.
Aubert set up Keast at the 63:51 mark to double the visitors' advantage and then scored himself with 9:55 to play. His fourth goal in three games this season was assisted by sophomore Griffin Mitchell, who earned his first career point.
The shutout was the second in as many days for junior goalkeeper Jan Roessler, who made a pair of saves in the first half and four in the final 45 minutes.
The visitors outshot the Cougars 24-8 on the day.
The Foresters improved to 2-0-1 on the year while Concordia Chicago fell to 1-1-0.
Lake Forest's next two games will be played in California, beginning with a 7:00 p.m. (PT) contest on Friday at California Lutheran University. The team will also take on Occidental College on Sunday at 11:00 a.m. (PT).