Several vulnerabilities have been discovered in Samba, a SMB/CIFS file,
print, and login server for Unix.
Stefan Metzmacher reported that SMB1 client connections can be
downgraded to plaintext authentication.
Andrew Bartlett reported that Samba may map domain users to local
users in an undesired way, allowing for privilege escalation. The
update introduces a new parameter "min domain uid" (default to 1000)
to not accept a UNIX uid below this value.
Andrew Bartlett reported that Samba as AD DC, when joined by an
RODC, did not confirm if the RODC was allowed to print a ticket for
that user, allowing an RODC to print administrator tickets.
Andrew Bartlett reported that Samba as AD DC, did not always rely on
the SID and PAC in Kerberos tickets and could be confused about the
user a ticket represents. If a privileged account was attacked this
could lead to total domain compromise.
Andrew Bartlett reported that Samba as a AD DC did not provide a way
for Linux applications to obtain a reliable SID (and samAccountName)
in issued tickets.
Andrew Bartlett reported that Samba as AD DC did not do sufficient
access and conformance checking of data stored, potentially allowing
total domain compromise.
William Ross reported that the Samba AD DC RPC server can use memory
that was free'd when a sub-connection is closed, resulting in denial
of service, and potentially, escalation of privileges.
Stefan Metzmacher reported that if a client to a Samba server sent a
very large DCE/RPC request, and chose to fragment it, an attacker
could replace later fragments with their own data, bypassing the
For the stable distribution (bullseye), these problems have been fixed in version 2:4.13.13+dfsg-1~deb11u2.
We recommend that you upgrade your samba packages.