CGA-4gr3-q9wm-59rc

Summary

QUIC's Connection ID Mechanism vulnerable to Memory Exhaustion Attack

Description

An attacker can cause its peer to run out of memory by sending a large number of NEW_CONNECTION_ID frames that retire old connection IDs. The receiver is supposed to respond to each retirement frame with a RETIRE_CONNECTION_ID frame. The attacker can prevent the receiver from sending out (the vast majority of) these RETIRE_CONNECTION_ID frames by collapsing the peers congestion window (by selectively acknowledging received packets) and by manipulating the peer's RTT estimate.

I published a more detailed description of the attack and its mitigation in this blog post: https://seemann.io/posts/2024-03-19-exploiting-quics-connection-id-management/. I also presented this attack in the IETF QUIC working group session at IETF 119: https://youtu.be/JqXtYcZAtIA?si=nJ31QKLBSTRXY35U&t=3683

There's no way to mitigate this attack, please update quic-go to a version that contains the fix.