Don't allow multiple INTRODUCE1s on the same circuit
|Reported by:||asn||Owned by:|
|Component:||Core Tor/Tor||Version:||Tor: 0.2.7|
|Severity:||Keywords:||026-backport, 025-backport, 024-backport, 027-triaged-1-in, SponsorU, 2016-bug-retrospective|
Currently, it seems like clients are able to send multiple INTRODUCE1 cells to the IP. The result is that many INTRODUCE2 cells reach the HS, which means that the HS will try to establish multiple rendezvous circuits.
This gives a better position to attackers who want to flood a HS with rendezvous circuits (like #15463), since with a single circuit they can cause hundreds of rendezvous.
We should fix this in the IP-side, by closing the circuit after sending the INTRODUCE_ACK to the client. An alternate behavior, is to change the state of the circuit after INTRODUCE1 is received and close it if more such cells are received.
Change History (31)
comment:5 Changed 2 years ago by nickm
- Keywords 025-backport added
- Milestone changed from Tor: 0.2.7.x-final to Tor: 0.2.6.x-final
comment:9 in reply to: ↑ 3 ; follow-ups: ↓ 10 ↓ 12 Changed 2 years ago by asn
comment:25 Changed 2 years ago by isabela
- Keywords 027-triaged-1-in SponsorU added
- Points set to small
- Priority changed from normal to major
- Version set to Tor: 0.2.7
comment:29 Changed 2 years ago by dgoulet
- Resolution set to fixed
- Status changed from needs_review to closed