Stefan Gast

The issue is related to a timing side channel in the TCP protocol, making it easier for remote attackers to infer the content of one TCP connection from a client system to any server. This can occur when the client system is concurrently obtaining TCP data at a slow rate from an attacker-controlled server. The attack can begin by measuring RTTs via the TCP segments whose role is to provide an ACK control bit and an Acknowledgment Number.

The issue is related to execution unit scheduler contention, which may lead to a side channel vulnerability. By measuring the contention level on scheduler queues, an attacker may potentially leak sensitive information. This vulnerability, known as SQUIP, affects AMD processors and allows an attacker to determine data used in other processes or virtual machines or establish a hidden communication channel between them, bypassing system access control mechanisms.