In the era of cloud computing, the focus of cyber criminals has shifted from traditional IT infrastructures to the cloud. Cyber forensic investigations in the cloud present several challenges due to legal obligations, technical limitations, and the dynamic nature of cloud resources. For instance, access to digital assets is crucial for practical analysis but is often hindered, as investigators may not have complete access to disk images or log files. The mainstream forensic frameworks and solutions for identifying, retrieving, and preserving evidence in the cloud are lacking. Yet, NIST has identified 65 cloud forensics challenges, with 13 related to log files alone. The preservation and integrity of forensic evidence are the backbones of a digital forensic investigation, and the chain of custody proves the authenticity of the evidence. However, cloud environments are not designed to handle digital evidence with integrity, leading to severe issues when presenting evidence in a court of law. This paper delves into the challenges of cloud forensics investigation, focusing on log files, and aims to identify potential solutions and frameworks to support the chain of custody. For that purpose, the authors evaluate the suitability of blockchain technology for maintaining a proper chain of custody of log files in the cloud. A prototype is implemented to serve as a proof of concept.