#VU49937 Security features bypass in coTURN - CVE-2020-26262

Vulnerability identifier: #VU49937

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-26262

CWE-ID: CWE-254

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
coTURN
Server applications / Other server solutions

Vendor: coTURN

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists in the way the Coturn handles CONNECT requests with XOR-PEER-ADDRESS set to "0.0.0.0". A remote attacker can send specially crafted request to the affected server and force Coturn relay on the loopback addresses, such as 127.x.x.x and ::1, which is disabled by default.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

coTURN: 4.0.0.0 - 4.5.1.3

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External links
https://github.com/coturn/coturn/blob/57180ab60afcaeb13537e69ae8cb8aefd8f3f546/ChangeLog#L48
https://github.com/coturn/coturn/commit/abfe1fd08d78baa0947d17dac0f7411c3d948e4d
https://github.com/coturn/coturn/security/advisories/GHSA-6g6j-r9rf-cm7p
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G54UIUFTEC6RLPOISMB6FUW7456SBZC4/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/M4CJOPAQT43MYAFU3UROGLEXN3Z6RS4H/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.