Combine vinegar, soy sauce, oil, catsup and garlic.
Place steak in utility dish or plastic bag and pour marinade over it, turning to coat.
Cover dish or tie bag securely and place in pan. Marinate in refrigerator 6 hours or overnight, turning at least once.
Remove steak from marinade and place on rack in broiler pan with surface of meat 4 inches from heat.
Broil 7 to 10 minutes on each side, depending upon degree of doneness desired (rare or medium).