Abstract
Servers that consist of multiple nodes and sockets are interconnected
together with a high-bandwidth, low latency
processor interconnect network, such as Intel QPI or AMD
Hypertransport technologies. The different nodes exchange
packets through routers which communicate with other routers.
A key component of a router is the routing table which determines
which output port an arriving packet should be
forwarded through. However, because of the flexibility (or
programmability) of the routing tables, we show that it can
result in security vulnerability. We describe the procedures
for how the routing tables in a processor-interconnect router
can be modified. Based on these modifications, we propose
new system attacks in a server, which include both performance
attacks by degrading the latency and/or the bandwidth
of the processor interconnect as well as a livelock attack
that hangs the system. We implement these system
on an 8-node AMD server and show how performance can
be significantly degraded. Based on this vulnerability, we
propose alternative solutions that provide various trade-off
in terms of flexibility and cost while minimizing the routing
table security vulnerability.
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