Apache Syncope offers the ability to extend / customize the base behavior on every deployment by allowing to provide custom implementations of a few Java interfaces; such implementations can be provided either as Java or Groovy classes, with the latter being particularly attractive as the machinery is set for runtime reload. Such a feature has been available for a while, but recently it was discovered that a malicious administrator can inject Groovy code that can be executed remotely by a running Apache Syncope Core instance. Users are recommended to upgrade to version 3.0.14 / 4.0.2, which fix this issue by forcing the Groovy code to run in a sandbox.

In Apache Syncope 2.1.X releases prior to 2.1.7, when the Flowable extension is enabled, an administrator with workflow entitlements can use Shell Service Tasks to perform malicious operations, including but not limited to file read, file write, and code execution.

An administrator with workflow definition entitlements can use DTD to perform malicious operations, including but not limited to file read, file write, and code execution.