Diameter Flooding

In telecommunications, Diameter Flooding is a denial-of-service attack that overwhelms a Diameter peer (HSS, MME, PCRF, DRA) with high-rate requests on interfaces such as S6a, S9, or Sh. It can disrupt authentication, policy, and roaming. Defenses include rate limiting at the Diameter Edge Agent, origin-realm whitelisting, and category-based screening.

Categories: Core NetworkSignalingRoaming and Interconnect

Diameter Flooding in context

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

To place Diameter Flooding in the wider telecom-security picture, review FS.07, Diameter, FS.19, HSS, Pentest and Defense in Depth.

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