Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
0

CVE-2020-26262

Disclosure Date: January 13, 2021
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

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.

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CVSS V3 Severity and Metrics
Base Score:
7.2 High
Impact Score:
2.7
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Changed
Confidentiality (C):
Low
Integrity (I):
Low
Availability (A):
None

General Information

Vendors

  • coturn project,
  • fedoraproject

Products

  • coturn,
  • fedora 32,
  • fedora 33
Technical Analysis