In this article we show that coding theory can be exploited efficiently for the cryptanalysis of hash functions. We will mainly focus on SHA-1. We present different linear codes that are used to find low-weight differences that lead to a collision. We extend existing approaches and include recent results in the cryptanalysis of hash functions. With our approach we are able to find differences with very low weight. Based on the weight of these differences we conjecture the complexity for a collision attack on the full SHA-1.