Controlled SSRF through URL in the WireMock

WireMock is a tool for mocking HTTP services. WireMock can be configured to only permit proxying (and therefore recording) to certain addresses. This is achieved via a list of allowed address rules and a list of denied address rules, where the allowed list is evaluated first.

Until WireMock Webhooks Extension 3.0.0-beta-15, the filtering of target addresses from the proxy mode DID NOT work for Webhooks, so the users were potentially vulnerable regardless of the `limitProxyTargets` settings. Via the WireMock webhooks configuration, POST requests from a webhook might be forwarded to an arbitrary service reachable from WireMock’s instance. For example, If someone is running the WireMock docker Container inside a private cluster, they can trigger internal POST requests against unsecured APIs or even against secure ones by passing a token, discovered using another exploit, via authentication headers. This issue has been addressed in versions 2.35.1 and 3.0.3 of wiremock. Wiremock studio has been discontinued and will not see a fix. Users unable to upgrade should use external firewall rules to define the list of permitted destinations.