In spite of being replaced by AES (advanced encryption standard), DES (data encryption standard) still plays an important role as encryption standard. DES and the triple DES are still widely used in many areas, especially in the financial sector. Recently, some new cryptanalytic techniques are introduced and of which the Rectangle attack and the Boomerang attack had proved to be very powerful. Therefore, it is necessary to re-evaluate the effects that these new cryptanalytic techniques may have on DES. This paper examines the strength of DES against the Rectangle attack and the Boomerang attack. By using the best differential characteristic of DES, the paper gets an attack against up to 12-round DES using the Rectangle attack and an attack against 11-round DES using the Boomerang attack respectively. The Rectangle attack on 12-round DES requires 2⁶² chosen plaintexts and the time complexity is equivalent to 2⁴² 12-round encryptions, while the Boomerang attack on 11-round DES requires 2⁵⁸ adaptive chosen plaintexts and ciphertexts and the time complexity is equivalent to 2³⁸ 11-round encryptions. Because the differential characteristics used in the attacks are all the best ones, it is believed that the attacks are the best results that the Rectangle attack and the Boomerang attack can get on DES.