As per upstream advisory: The NetBIOS over TCP/IP name resolution protocol is implemented as a UDP datagram on port 137. The AD DC client and server-side processing code for NBT name resolution will enter a tight loop if a UDP packet with 0 data length is received. The client for this case is only found in the AD DC side of the codebase, not that used by the the member server or file server.
Acknowledgments: Name: the Samba project Upstream: Martin von Wittich (IServ GmbH), Wilko Meyer (IServ GmbH)
Mitigation: The NetBIOS over TCP/IP name resolution protocol is implemented as a UDP datagram on port 137. The AD DC client and server-side processing code for NBT name resolution will enter a tight loop if a UDP packet with 0 data length is received. The client for this case is only found in the AD DC side of the codebase, not that used by the the member server or file server.
External References: https://www.samba.org/samba/security/CVE-2020-14303.html
Created samba tracking bugs for this issue: Affects: fedora-all [bug 1853259]
Upstream patch: https://github.com/samba-team/samba/commit/3cc0f1eeda5f133532dda31eef9fc1b394127e50
Statement: This flaw does not affect the version of samba shipped with Red Hat Enterprise Linux and Red Hat Gluster Storage 3 because there is no support for samba as Active Directory Domain Controller.