defirisk.co
rubric v1.7.0

Bridge validator co-hosting

A cross-chain & bridge factor in the v1.7.0 rubric. Measured per protocol on a s cadence.

Methodology how we score#

What this measures
This factor checks whether bridge validators share ASN (Autonomous System Number), data-centre operator, or cloud custodian — indicating that multiple validators could be taken offline or compromised by a single infrastructure event. Assessment combines bridge documentation with OSINT on validator operator infrastructure. This factor applies only to bridge-touching protocols; non-bridge protocols show this factor as N/A.

Why it matters
Physical and infrastructure co-location transforms a nominally independent validator set into a correlated failure group. A 7-of-10 bridge with all validators hosted on the same AWS region effectively has a single infrastructure point of failure — a region outage or targeted attack against that provider can simultaneously compromise the quorum. The T-01 evidence base links co-hosting patterns to approximately 3 protocols in the hack database, including bridge incidents where signer-set compromise was facilitated by shared infrastructure. Harmony Bridge validators reportedly shared operational infrastructure that reduced the effective independence of its 2-of-5 threshold.

Green / Yellow / Red
Green is scored when validators use diverse cloud providers, geographic regions, and independent node operators with documented independence. Yellow is scored when some validators share a cloud provider or region but no single provider controls a quorum. Red is scored when validators sharing a single provider or region constitute a quorum, or when all validators are operated by the same entity.

Common gray cases
Gray is applied when validator infrastructure cannot be determined from public documentation and OSINT cannot confidently identify hosting relationships.

Notable historical examples
No cross-hacked incidents are currently linked in the database for this factor.

Measurement what to look for#

Determine whether validators share ASN or data-center/custodian per on-chain and OSINT inference.

Data & output #

Data source
Validator address list (from F148) + Chainalysis/TRM infrastructure OSINT + ASN lookup
Output format
Green / Yellow / Red
Evidence artifact
Validator address list + ASN/custodian inference per validator + co-hosting flag
Confidence signal
green = validators demonstrably on independent infrastructure; yellow = partial evidence or insufficient data; red = majority of validators share ASN or custodian; gray = bridge not identified or validator set not public

Scored protocols 0 carry this factor#

No protocols have been scored for this factor yet.

Linked hacks no historical incidents linked#

No historical incidents are linked to this factor.
rubric_version v1.7.0factor RD-F-150category 10carried 0critical no