bem visto: os defacements são em si pouco graves mas revelam a existência de ameaças e vulnerabilidades que não o são:
"I may be in the minority by stating the following, however, I believe that web defacements are a serious problem and are a critical barometer for estimating exploitable vulnerabilities in websites. Defacement statistics are valuable as they are one of the few incidents that are publicly facing and thus can not easily be swept under the rug.
The resulting risk of a web defacement might be low because the the impact may not be deemed a high enough severity for particular organizations. What most people are missing, however, is that the threat and vulnerability components of the equation still exist."
do blog Tactical Web Application Security (post)