CVE-2020-26262
Publication date 11 January 2021
Last updated 24 July 2024
Ubuntu priority
Coturn is free open source implementation of TURN and STUN Server. Coturn before version 4.5.2 by default does not allow peers to connect and relay packets to loopback addresses in the range of `127.x.x.x`. However, it was observed that when sending a `CONNECT` request with the `XOR-PEER-ADDRESS` value of `0.0.0.0`, a successful response was received and subsequently, `CONNECTIONBIND` also received a successful response. Coturn then is able to relay packets to the loopback interface. Additionally, when coturn is listening on IPv6, which is default, the loopback interface can also be reached by making use of either `[::1]` or `[::]` as the peer address. By using the address `0.0.0.0` as the peer address, a malicious user will be able to relay packets to the loopback interface, unless `--denied-peer-ip=0.0.0.0` (or similar) has been specified. Since the default configuration implies that loopback peers are not allowed, coturn administrators may choose to not set the `denied-peer-ip` setting. The issue patched in version 4.5.2. As a workaround the addresses in the address block `0.0.0.0/8`, `[::1]` and `[::]` should be denied by default unless `--allow-loopback-peers` has been specified.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| coturn | ||
| 20.04 LTS focal |
Fixed 4.5.1.1-1.1ubuntu0.20.04.2
|
|
| 18.04 LTS bionic |
Fixed 4.5.0.7-1ubuntu2.18.04.3
|
|
| 16.04 LTS xenial |
Fixed 4.5.0.3-1ubuntu0.4
|
|
| 14.04 LTS trusty | Not in release |
Notes
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
7.2 · High
|
| Attack vector | Network |
| Attack complexity | Low |
| Privileges required | None |
| User interaction | None |
| Scope | Changed |
| Confidentiality | Low |
| Integrity impact | Low |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N |
References
Related Ubuntu Security Notices (USN)
- USN-4690-1
- coTURN vulnerability
- 11 January 2021