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.

The remote Fedora 32 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-32d0068851 advisory.

  - 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. (CVE-2020-26262)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Fedora 33 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-dee141fc61 advisory.

  - 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. (CVE-2020-26262)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

A flaw was discovered in coturn, a TURN and STUN server for VoIP. By default coturn does not allow peers on the loopback addresses (127.x.x.x and ::1). A remote attacker can bypass the protection via a specially crafted request using a peer address of '0.0.0.0' and trick coturn in relaying to the loopback interface. If listening on IPv6 the loopback interface can also be reached by using either [::1] or [::] as the address.

For Debian 9 stretch, this problem has been fixed in version 4.5.0.5-1+deb9u3.

We recommend that you upgrade your coturn packages.

For the detailed security status of coturn please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/coturn

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has a package installed that is affected by a vulnerability as referenced in the USN-4690-1 advisory.

    It was discovered that coTURN allowed peers to connect and relay packets to loopback addresses in the     range of 127.x.x.x. A malicious user could use this vulnerability to insert packages into the loopback     interface.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

A flaw was discovered in coturn, a TURN and STUN server for VoIP. By default coturn does not allow peers on the loopback addresses (127.x.x.x and ::1). A remote attacker can bypass the protection via a specially crafted request using a peer address of '0.0.0.0' and trick coturn in relaying to the loopback interface. If listening on IPv6 the loopback interface can also be reached by using either [::1] or [::] as the address.

ID	Name	Product	Family	Severity
145152	Fedora 32 : coturn (2021-32d0068851)	Nessus	Fedora Local Security Checks	high
145112	Fedora 33 : coturn (2021-dee141fc61)	Nessus	Fedora Local Security Checks	high
144924	Debian DLA-2522-1 : coturn security update	Nessus	Debian Local Security Checks	high
144870	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : coTURN vulnerability (USN-4690-1)	Nessus	Ubuntu Local Security Checks	high
144866	Debian DSA-4829-1 : coturn - security update	Nessus	Debian Local Security Checks	high

Detections

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CVE-2020-26262

high

Tenable Plugins

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high

high

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high