CVE-2022-24777 is a vulnerability identified in grpc-swift, the Swift language implementation of the gRPC framework, which is widely used for remote procedure calls (RPC) in distributed systems. The vulnerability is classified as CWE-617, a reachable assertion flaw, which occurs due to incorrect logic in handling GOAWAY frames within grpc-swift versions prior to 1.7.2. GOAWAY frames are part of the HTTP/2 protocol used by gRPC to indicate that a server intends to close a connection gracefully. The flawed logic allows an attacker to send a crafted sequence of frames that triggers an assertion failure in the server code. This assertion failure causes the grpc-swift server to crash, resulting in a denial of service (DoS) condition. The attack requires minimal resources and effort, as the crafted frames are easy to construct and send. The impact on availability is significant because the server crash drops all in-flight connections and requests, disrupting service continuity. No known workarounds exist, but the issue is resolved in grpc-swift version 1.7.2 and later. There are no known exploits in the wild at this time, but the vulnerability’s low exploitation complexity and high impact on availability make it a critical concern for systems relying on grpc-swift servers below version 1.7.2.

For European organizations, the primary impact of CVE-2022-24777 is on service availability. Organizations using grpc-swift servers in their infrastructure—particularly those running versions earlier than 1.7.2—are at risk of denial of service attacks that can disrupt critical applications and services. This can affect sectors such as finance, healthcare, telecommunications, and public services, where gRPC is commonly used for microservices communication and backend APIs. The disruption of services can lead to operational downtime, loss of customer trust, and potential regulatory non-compliance related to service availability and reliability under frameworks like GDPR. Additionally, the crash of grpc-swift servers could indirectly impact data integrity if transactions or communications are abruptly terminated. Although no known exploits are currently active, the ease of exploitation means threat actors could develop attacks targeting vulnerable systems, especially in environments where swift-based gRPC implementations are prevalent. The lack of workarounds further elevates the risk until systems are patched.

1. Immediate upgrade of all grpc-swift server instances to version 1.7.2 or later to apply the official fix for the vulnerability. 2. Conduct an inventory audit to identify all systems and services using grpc-swift, including internal and third-party applications, to ensure comprehensive patching. 3. Implement network-level filtering to restrict or monitor incoming HTTP/2 traffic, especially GOAWAY frames, from untrusted sources to reduce exposure to crafted frame attacks. 4. Deploy runtime monitoring and alerting for grpc-swift server crashes or abnormal termination events to enable rapid incident response. 5. Where possible, isolate grpc-swift servers behind application gateways or proxies that can perform protocol validation and reject malformed frames. 6. Integrate grpc-swift version checks into CI/CD pipelines to prevent deployment of vulnerable versions. 7. Engage with vendors and third-party service providers to confirm their grpc-swift versions are patched or mitigated. 8. Prepare incident response plans specifically addressing grpc-swift DoS scenarios to minimize downtime and service disruption.