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, 2 minutes.
Add the shallots and bell pepper and cook 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.