CVE-2020-4067

In coturn before version 4.5.1.3, there is an issue whereby STUN/TURN response buffer is not initialized properly. There is a leak of information between different client connections. One client (an attacker) could use their connection to intelligently query coturn to get interesting bytes in the padding bytes from the connection of another client. This has been fixed in 4.5.1.3.

Weakness

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable’s type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00010.html
• https://github.com/coturn/coturn/blob/aab60340b201d55c007bcdc853230f47aa2dfdf1/ChangeLog#L15
• https://github.com/coturn/coturn/issues/583
• https://github.com/coturn/coturn/security/advisories/GHSA-c8r8-8vp5-6gcm
• https://lists.debian.org/debian-lts-announce/2020/07/msg00002.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5G35UBNSRLL6SYRTODYTMBJ65TLQILUM/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNJJO77ZLGGFJWNUGP6VDG5HPAC5UDBK/
• https://usn.ubuntu.com/4415-1/
• https://www.debian.org/security/2020/dsa-4711