Routing under siege: how traffic engineering decisions facilitate prefix hijackings#

Renan Paredes Barreto (Universidade Federal do Rio Grande — FURG; slides also credit Leandro Bertholdo and Pedro Marcos)

• Why: Controlled, real-Internet experiments that quantify how operators' own traffic engineering choices change hijack exposure — turning received wisdom ("prepends are harmless") into measured numbers with direct configuration implications.
• What: Using the PEERING testbed (real BGP announcements from five PoPs: Amsterdam, UFMG, Seoul, Johannesburg, and a Northeast-US site), the authors ran type-0 hijack experiments in controlled windows (Nov 2024–Feb 2025) against 127,421 responsive data-plane targets across 45,462 ASes, measuring both control-plane reach (RIS Live monitors) and data-plane impact (ping responses). Key results: increasing AS-path prepends by the victim increases hijack impact; ASes can be significantly impacted even without prepending; more-specific-prefix hijacks affect even well-connected ASes with fairly uniform impact; and impact varies materially by PoP/location.
• How: Victim and hijacker announce the same prefix from different PEERING sites; impact percentage = monitors/hosts selecting the hijacker's path vs. the victim's; each iteration varies TE technique (prepend count, prefix length, selective announcements), AS locations, and connectivity.
• Where applicable: Any operator using prepends or managing announcement granularity — the practical lesson (heavy prepending measurably increases sub-prefix hijack exposure) is broadly applicable. Constraints: IPv4 only, type-0 hijacks only, no ROAs created — findings are scenario-specific rather than universal.