CWE-1331 describes a Network on Chip (NoC) that does not isolate its on-chip fabric and internal resources, so they are shared between trusted and untrusted agents. That sharing creates timing channels.
How it happens
NoCs have many internal resources that carry packets from different trust domains: internal buffers, crossbars and switches, individual ports and channels. Shared resources mean contention, and contention means one domain can feel the traffic of another. An attacker can read that interference as a timing channel and infer data that belongs to a trusted agent. It can also reduce throughput and increase latency.
The record lists CVE-2021-33096: improper isolation of a shared resource in a network-on-chip leads to denial of service.
What an attacker gains
Confidentiality, because data belonging to a trusted agent can be inferred, and availability, through increased resource consumption. The attack may show up as noticeably higher resource use.
How to find it
MITRE suggests manual analysis: send marker flags through the interfaces and examine which users can read or change them, to verify that isolation is in place and effective.
How to fix it
Implement priority-based arbitration inside the NoC, and use dedicated buffers or virtual channels to route secret data from trusted agents.
Quick check
What makes the leak a timing channel?
Shared resources cause contention. The interference between trust domains is measurable, so an attacker can infer a trusted agent's data from timing.
