Samba has just released new security patches for two critical vulnerabilities that could allow unprivileged remote attackers to launch DoS attacks against servers and change any other users' passwords, including admin's.

Samba is open-source software (re-implementation of SMB networking protocol) that runs on the majority of operating systems available today, including Windows, Linux, UNIX, IBM System 390, and OpenVMS.

Samba allows non-Windows operating systems, like GNU/Linux or Mac OS X, to share network shared folders, files, and printers with Windows operating system.

Denial of service vulnerability has been assigned CVE-2018-1050 that affects all versions of Samba from 4.0.0 onwards and can be exploited when the RPC spoolss service is configured to be run as an external daemon.

"Missing input sanitization checks on some of the input parameters to spoolss RPC calls could cause the print spooler service to crash. If the RPC spoolss service is left by default as an internal service, all a client can do is crash its own authenticated connection." Samba advisory says.

The second vulnerability, assigned CVE-2018-1057, allows unprivileged authenticated users to change any other users' passwords, including admin users.

This flaw exists on all versions of Samba from 4.0.0 onwards, and works only in Samba Active Directory DC, as it doesn’t validate permissions of the users while they modify passwords over LDAP.

A large number of users might potentially be at risk, because Samba ships with a wide range of Linux distributions.

The maintainers of Samba have addressed both vulnerabilities with the release of new Samba versions 4.7.6, 4.6.14 and 4.5.16.

Administrators who are running an older version of Samba can check this page if a contributed patch is available.