A vacuum operated brake booster, comprises a casing including a base defining at least one hole, and at least one tube extending through the casing and configured to receive a screw for fastening the brake booster to a wall of a passenger compartment of a vehicle. The tube defines a rear end with a peripheral fold forming a rear groove, and an extension extending beyond the rear groove, the extension defining a first outer edge and being configured to be folded toward an outer side of the tube to form a crimping lip. The at least one hole is bordered by a recessed ring having a form complementary to that of the rear groove of the rear end of the at least one tube. The extension is configured to be folded above a second outer edge of the recessed ring and blocked in the groove.