Eclipse Foundation Eclipse Ditto: Improper Neutralization of Special Elements Used in a Template Engine

In Eclipse Ditto versions [1.3.0, 3.9.6], the ImplicitThingCreationMessageMapper of the connectivity service builds a CreateThing command by substituting placeholder values (e.g. {{ header:device_id }}) resolved from inbound message headers into a pre-configured JSON "thing" template as raw, un-escaped strings, and then parses the resulting string as JSON. Because the placeholder engine performs no JSON escaping and is unaware of the surrounding JSON string context, a resolved value containing a double-quote character can break out of its string and inject additional JSON structure. When a connection is configured to use this mapper with a template that reflects a header whose value a publishing device can control (for example an MQTT 5 user property, an AMQP 1.0 application property, or a Kafka record header), an attacker able to publish on that connection can inject an inline _policy object. The inline policy overrides the administrator-configured policyId, letting the attacker assign an arbitrary access-control policy to the newly created digital twin — gaining full read/write access to it and potentially revoking the legitimate owner's access, with no administrator interaction. Exploitation requires all of the following: the connection uses the (non-default) ImplicitThingCreation mapper; its template reflects an attacker-controllable header; and, for the policy-override impact, the connection's authorization subjects are permitted to create policies (the default). Deployments that restrict the connection's subjects to thing creation only via the entity-creation configuration are not affected by the policy-override impact.

The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.