In the scenario where your company sells Software as a Service (SaaS) and is hosted on the cloud using it as a Platform as a Service (PaaS), your company is responsible for eradicating malware in your customer's database. This is because, as the SaaS provider, your company manages the software and is responsible for its security and maintenance, including the databases that store customer data. While the PaaS provider is responsible for the underlying infrastructure, platform, and possibly some middleware security aspects, the application layer security, including data and application management, falls to the SaaS provider. Building management wouldnot be involved in digital security matters, and while customers are responsible for their data, the actual software maintenance and security in a SaaS model are the provider's responsibility.
References:Incident Handler (CREST CPTIA) certification materials often discuss cloud service models (IaaS, PaaS, SaaS) and their associated security responsibilities, highlighting the importance of understanding who is responsible for what in cloud environments.