Assessing the Threats Targeting Low Latency Traffic: the Case of L4S

Marius Letourneau (1) , Kouame Boris N'Djore (1) , Guillaume Doyen (2) , Bertrand Mathieu (3) , Remi Cogranne (1) , Huu Nghia Nguyen (4)

1 UTT - Université de Technologie de Troyes
2 IMT Atlantique - SRCD - Département Systèmes Réseaux, Cybersécurité et Droit du numérique
3 Orange Innovation
4 Montimage [Paris]

New types of services with low-latency requirements have become a major challenge for the future Internet. Many optimizations, all targeting the latency reduction have been proposed. Among them, jointly re-architecting congestion control and active queue management has been particularly considered. In this effort, the L4S (Low Latency, Low Loss and Scalable Throughput) proposal aims at allowing both classic and lowlatency traffic to cohabit within a single node architecture. Although this architecture sounds promising for latency improvement, it can be exploited by an attacker to perform malicious actions whose purposes are to defeat its low-latency feature and consequently make their supported applications unusable. In this paper, we analyze a set of weaknesses of L4S architecture and show that application-layer protocols such as QUIC can easily be hacked in order to exploit the over-sensitivity of those new services to network variations. By implementing undesirable flows in a real testbed and evaluating how they impact the proper delivery of low-latency flows, we demonstrate their reality and relevance for future deployments.

Domains: Networking and Internet Architecture [cs.NI]

Marius Letourneau, Kouame Boris N'Djore, Guillaume Doyen, Bertrand Mathieu, Remi Cogranne, et al.. Assessing the Threats Targeting Low Latency Traffic: the Case of L4S. 2021 17th International Conference on Network and Service Management (CNSM), Oct 2021, Izmir, Turkey. pp.544-550, ⟨10.23919/CNSM52442.2021.9615534⟩. ⟨hal-04008210⟩