Headline
CVE-2020-14303: Empty UDP packet DoS in Samba AD DC nbtd
A flaw was found in the AD DC NBT server in all Samba versions before 4.10.17, before 4.11.11 and before 4.12.4. A samba user could send an empty UDP packet to cause the samba server to crash.
Description Huzaifa S. Sidhpurwala 2020-06-26 04:44:42 UTC
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.
Comment 1 Huzaifa S. Sidhpurwala 2020-06-26 04:44:46 UTC
Acknowledgments:
Name: the Samba project Upstream: Martin von Wittich (IServ GmbH), Wilko Meyer (IServ GmbH)
Comment 2 Huzaifa S. Sidhpurwala 2020-06-26 04:46:01 UTC
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.
Comment 4 Huzaifa S. Sidhpurwala 2020-07-02 09:37:12 UTC
Created samba tracking bugs for this issue:
Affects: fedora-all [bug 1853259]
Comment 6 Hardik Vyas 2020-07-02 11:52:38 UTC
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.