In a large skillet, heat the oil over medium-high heat. Add the garlic and chiles and cook until aromatic, about 30 seconds. Add the steak and cook, stirring frequently, for 2 minutes. Add the shallots and bell pepper and cook for 1 minute. Add the fish sauce, sweet soy sauce, black soy sauce and chili paste. Bring the mixture to a low simmer and cook, stirring frequently until the meat is cooked through and the vegetables are tender, about 3 minutes. Remove the skillet from the heat and stir in the basil and mint until wilted. Transfer to a serving dish and serve over steamed white rice.