A computer-implemented method for securing a service implemented on a computer network, wherein the service involves multiple network assets, the method comprising: identifying network assets (101-n) in the computer network used by the service, with describing logical dependencies of the network assets (101-n) in the computer network by a service model; identifying computer security vulnerabilities in one or more of the network assets (101-n), each computer security vulnerability having one or more vulnerability risk dimensions, wherein the computer security vulnerabilities are identified with determining a risk value for each vulnerability risk dimension, by using information obtained from one or more network security tools; based on the identified computer security vulnerabilities, determining an asset risk score for each of the network assets (101-n), based on the risk values of the vulnerability risk dimensions of the vulnerabilities in each of the network assets, by using an asset criticality value as a multiplier, wherein the asset criticality value indicates an importance of each network asset relative to other network assets, and by applying the criticality value to a sum of the one or more vulnerability risk dimensions as weighted by the risk value for each of the vulnerability risk dimensions; based on the determined asset risk scores of the network assets (101-n), determining a service risk score for the service, by processing the logical dependencies between the network assets in the service model and by aggregating the asset risk scores of the network assets (101-n) used by the service; and prioritizing implementation of one or more vulnerability remediation actions on the computer network to best reduce the service risk score and secure the service. identifying network assets (101-n) in the computer network used by the service, with describing logical dependencies of the network assets (101-n) in the computer network by a service model; identifying computer security vulnerabilities in one or more of the network assets (101-n), each computer security vulnerability having one or more vulnerability risk dimensions, wherein the computer security vulnerabilities are identified with determining a risk value for each vulnerability risk dimension, by using information obtained from one or more network security tools; based on the identified computer security vulnerabilities, determining an asset risk score for each of the network assets (101-n), based on the risk values of the vulnerability risk dimensions of the vulnerabilities in each of the network assets, by using an asset criticality value as a multiplier, wherein the asset criticality value indicates an importance of each network asset relative to other network assets, and by applying the criticality value to a sum of the one or more vulnerability risk dimensions as weighted by the risk value for each of the vulnerability risk dimensions; based on the determined asset risk scores of the network assets (101-n), determining a service risk score for the service, by processing the logical dependencies between the network assets in the service model and by aggregating the asset risk scores of the network assets (101-n) used by the service; and prioritizing implementation of one or more vulnerability remediation actions on the computer network to best reduce the service risk score and secure the service.