Abstract: Automated analysis techniques for lightweight block cipher algorithms have been a hot topic in recent research. The LLLWBC algorithm, proposed at the Inscrypt 2022 conference, is a novel low-latency lightweight block cipher that demonstrates excellent encryption and decryption performance in both software and hardware implementations. However, its security against emerging cryptanalytic techniques requires further investigation. In this paper, a new technique for constructing word-based propagation trails in block cipher algorithms is introduced, an automated detection method for seven distinct algebraic structures is proposed, then an automated search approach for integral distinguishers is also proposed based on these algebraic structures. Furthermore, the construction method for key guessing trails during the key recovery process of integral attacks is investigated, the optimal key guessing set can be obtained by using this method. Based on the proposed method, we construct a 9-round integral distinguisher for LLLWBC with a data complexity of 2^52 plaintext blocks, which are one rounds longer than the distinguishers given by the designers. Subsequently, based on the obtained 9-round integral distinguisher, a 12-round key-recovery attack of LLLWBC is proposed, which requires the data complexity of about 2^56.17 chosen data, the memory complexity of about 2^72 128-bit guess key and 2^52 64-bit ciphertexts, the time complexity of about 2^122.09 times encryptions of 12-round LLLWBC. Experimental results demonstrate that the 12-round LLLWBC algorithm is vulnerable to integral attacks, while the full 21-round LLLWBC maintains a sufficient security margin. The construction method of integral distinguisher and key recovery technique proposed in this paper can also be applied to other word-oriented block ciphers.