In Eclipse Jetty, versions <=9.4.57, <=10.0.25, <=11.0.25, <=12.0.21, <=12.1.0.alpha2, an HTTP/2 client may trigger the server to send RST_STREAM frames, for example by sending frames that are malformed or that should not be sent in a particular stream state, therefore forcing the server to consume resources such as CPU and memory.
For example, a client can open a stream and then send WINDOW_UPDATE frames with window size increment of 0, which is illegal. Per specification https://www.rfc-editor.org/rfc/rfc9113.html#name-window_update , the server should send a RST_STREAM frame. The client can now open another stream and send another bad WINDOW_UPDATE, therefore causing the server to consume more resources than necessary, as this case does not exceed the max number of concurrent streams, yet the client is able to create an enormous amount of streams in a short period of time.
The attack can be performed with other conditions (for example, a DATA frame for a closed stream) that cause the server to send a RST_STREAM frame.
Links:
The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system. There are at least three distinct scenarios which can commonly lead to resource exhaustion:
Resource exhaustion problems are often result due to an incorrect implementation of the following situations:
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.