Ensuring the web server logs are intact and secured is crucial in the initial steps of an investigation into a web application attack. These logs will provide valuable information about the traffic to the application leading up to and during the attack, enabling the investigation team to identify patterns and potentially malicious requests that could have led to the breach. Reviewing account integrity, examining user behavior, and performing a code review are all important steps as well, but they either build upon the information gathered from logs or are later steps in a thorough investigation process.