CVE-2017-8819
Publication date 3 December 2017
Last updated 25 August 2025
Ubuntu priority
Description
In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, the replay-cache protection mechanism is ineffective for v2 onion services, aka TROVE-2017-009. An attacker can send many INTRODUCE2 cells to trigger this issue.
From the Ubuntu Security Team
It was discovered that the replay-cache protection mechanism used by Tor is ineffective for v2 onion services. An attacker could possible use this to facilitate a traffic confirmation attack.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| tor | ||
| 18.04 LTS bionic |
Not affected
|
|
| 16.04 LTS xenial |
Fixed 0.2.9.14-1ubuntu1~16.04.2
|
|
| 14.04 LTS trusty |
Fixed 0.2.4.27-1ubuntu0.1
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
7.5 · High
|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | None |
| Availability impact | High |
| Vector | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |