Final answer:
The most likely type of attack being conducted when an account attempts to transfer large amounts of money, based on the review of a web server log, is a Session replay attack. This attack involves the fraudulent repetition or delay of a valid data transmission to impersonate a user.
Step-by-step explanation:
If a security analyst notices that a particular account is attempting to transfer large amounts of money by reviewing a web server log, the type of attack that is MOST likely being conducted could be a Session replay attack. Session replay involves the unauthorized capture and re-use of a valid session control message to gain unauthorized access to information or services in a computer system. It's a form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed. This can occur in the context of web applications when an attacker is able to steal or predict a session cookie and thereby impersonate a legitimate user, without their knowledge.
Other possible attacks like SQL injection (SQLi) and Cross-Site Request Forgery (CSRF) are also common security threats. SQLi is a code injection technique that might be used to attack data-driven applications by inserting malicious SQL statements into an entry field for execution. CSRF, on the other hand, is an attack that forces an end user to execute unwanted actions on a web application in which they are currently authenticated. However, these are less likely to be associated with the unauthorized money transfer scenario described.