1. A method comprising: identifying, using at least one data processing apparatus, a plurality of assets to scan in a network; identifying, using at least one data processing apparatus, a plurality of sets of known vulnerabilities in the plurality of assets, wherein identifying the plurality of sets of known vulnerabilities comprises identifying, for two or more of the plurality of assets, a respective set of known vulnerabilities previously detected as being present on the asset; identifying, using at least one data processing apparatus, a plurality of sets of new vulnerabilities in the plurality of assets, wherein identifying the plurality of sets of new vulnerabilities comprises identifying, for two or more of the plurality of assets, a respective set of new vulnerabilities for which the asset has not yet been scanned; selecting, using at least one data processing apparatus, a set of scripts comprising checks for particular vulnerabilities included in a union of the plurality of sets of known vulnerabilities and the plurality of sets of new vulnerabilities; and using the selected scripts to scan the plurality of assets for vulnerabilities.