Web-based online customer service is an important service for a service provider. It contains the user's important data and provides critical operational functions of the user’s services. It is the service provider’s responsibility to provide security to web-based online customer service. This Recommendation analyses the security threats of web-based online customer service in three aspects: network security, system security, service security It specifies security guidelines of web-based online customer service and corresponding security measures. It also proposes test procedures to verify the specified security requirements are satisfied by corresponding security measures. This Recommendation can help service providers to ensure their web-based online customer services’ security and protect benefits of their users.