A security analyst receives an email from a peer that includes a sample of code from a piece of malware found in an application running in the organization's staging environment. During the incident response process, it is determined the code was introduced into the environment as a result of a compromised laptop being used to harvest credentials and access the organization's code repository. While the laptop itself was not used to access the code repository, an attacker was able to leverage the harvested credentials from another system in the development environment to bypass the ACLs limiting access to the repositories. Which of the following controls MOST likely would have interrupted the kill chain in this attack?