Samba from version 4.9.0 and before version 4.9.3 is vulnerable to a NULL pointer de-reference. During the processing of an DNS zone in the DNS management DCE/RPC server, the internal DNS server or the Samba DLZ plugin for BIND9, if the DSPROPERTY_ZONE_MASTER_SERVERS property or DSPROPERTY_ZONE_SCAVENGING_SERVERS property is set, the server will follow a NULL pointer and terminate. There is no further vulnerability associated with this issue, merely a denial of service.

The remote host is affected by the vulnerability described in GLSA-202003-52 (Samba: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in Samba. Please review       the CVE identifiers referenced below for details.
  Impact :

    A remote attacker could possibly execute arbitrary code, cause a Denial       of Service condition, conduct a man-in-the-middle attack, or obtain       sensitive information.
  Workaround :

    There is no known workaround at this time.

According to the versions of the samba packages installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerabilities :

  - Samba from version 4.9.0 and before version 4.9.3 that     have AD DC configurations watching for bad passwords     (to restrict brute forcing of passwords) in a window of     more than 3 minutes may not watch for bad passwords at     all. The primary risk from this issue is with regards     to domains that have been upgraded from Samba 4.8 and     earlier. In these cases the manual testing done to     confirm an organisation's password policies apply as     expected may not have been re-done after the     upgrade.(CVE-2018-16857)

  - Samba from version 4.9.0 and before version 4.9.3 is     vulnerable to a NULL pointer de-reference. During the     processing of an DNS zone in the DNS management DCE/RPC     server, the internal DNS server or the Samba DLZ plugin     for BIND9, if the DSPROPERTY_ZONE_MASTER_SERVERS     property or DSPROPERTY_ZONE_SCAVENGING_SERVERS property     is set, the server will follow a NULL pointer and     terminate. There is no further vulnerability associated     with this issue, merely a denial of     service.(CVE-2018-16852)

  - A flaw was found in samba versions 4.9.x up to 4.9.13,     samba 4.10.x up to 4.10.8 and samba 4.11.x up to     4.11.0rc3, when certain parameters were set in the     samba configuration file. An unauthenticated attacker     could use this flaw to escape the shared directory and     access the contents of directories outside the     share.(CVE-2019-10197)

  - A flaw was found in samba 4.0.0 before samba 4.9.15 and     samba 4.10.x before 4.10.10. An attacker can crash AD     DC LDAP server via dirsync resulting in denial of     service. Privilege escalation is not possible with this     issue.(CVE-2019-14847)

  - A flaw was found in Samba, all versions starting samba     4.5.0 before samba 4.9.15, samba 4.10.10, samba 4.11.2,     in the way it handles a user password change or a new     password for a samba user. The Samba Active Directory     Domain Controller can be configured to use a custom     script to check for password complexity. This     configuration can fail to verify password complexity     when non-ASCII characters are used in the password,     which could lead to weak passwords being set for samba     users, making it vulnerable to dictionary     attacks.(CVE-2019-14833)

  - A flaw was found in the samba client, all samba     versions before samba 4.11.2, 4.10.10 and 4.9.15, where     a malicious server can supply a pathname to the client     with separators. This could allow the client to access     files and folders outside of the SMB network pathnames.
    An attacker could use this vulnerability to create     files outside of the current working directory using     the privileges of the client user.(CVE-2019-10218)

  - A flaw was found in the way an LDAP search expression     could crash the shared LDAP server process of a samba     AD DC in samba before version 4.10. An authenticated     user, having read permissions on the LDAP server, could     use this flaw to cause denial of     service.(CVE-2019-3824)

  - All Samba versions 4.x.x before 4.9.17, 4.10.x before     4.10.11 and 4.11.x before 4.11.3 have an issue, where     the S4U (MS-SFU) Kerberos delegation model includes a     feature allowing for a subset of clients to be opted     out of constrained delegation in any way, either     S4U2Self or regular Kerberos authentication, by forcing     all tickets for these clients to be non-forwardable. In     AD this is implemented by a user attribute     delegation_not_allowed (aka not-delegated), which     translates to disallow-forwardable. However the Samba     AD DC does not do that for S4U2Self and does set the     forwardable flag even if the impersonated client has     the not-delegated flag set.(CVE-2019-14870)

  - All Samba versions 4.x.x before 4.9.17, 4.10.x before     4.10.11 and 4.11.x before 4.11.3 have an issue, where     the (poorly named) dnsserver RPC pipe provides     administrative facilities to modify DNS records and     zones. Samba, when acting as an AD DC, stores DNS     records in LDAP. In AD, the default permissions on the     DNS partition allow creation of new records by     authenticated users. This is used for example to allow     machines to self-register in DNS. If a DNS record was     created that case-insensitively matched the name of the     zone, the ldb_qsort() and dns_name_compare() routines     could be confused into reading memory prior to the list     of DNS entries when responding to DnssrvEnumRecords()     or DnssrvEnumRecords2() and so following invalid memory     as a pointer.(CVE-2019-14861)

  - A flaw was found in samba's Heimdal KDC implementation,     versions 4.8.x up to, excluding 4.8.12, 4.9.x up to,     excluding 4.9.8 and 4.10.x up to, excluding 4.10.3,     when used in AD DC mode. A man in the middle attacker     could use this flaw to intercept the request to the KDC     and replace the user name (principal) in the request     with any desired user name (principal) that exists in     the KDC effectively obtaining a ticket for that     principal.(CVE-2018-16860)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the samba packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

  - A flaw was found in samba versions 4.9.x up to 4.9.13,     samba 4.10.x up to 4.10.8 and samba 4.11.x up to     4.11.0rc3, when certain parameters were set in the     samba configuration file. An unauthenticated attacker     could use this flaw to escape the shared directory and     access the contents of directories outside the     share.(CVE-2019-10197)

  - A null pointer dereference flaw was found in the Samba     DNS Management server when used as an Active Directory     Domain Controller. A remote attacker could use this     flaw to cause a denial of service (application     crash).Samba from version 4.9.0 and before version     4.9.3 is vulnerable to a NULL pointer de-reference.
    During the processing of an DNS zone in the DNS     management DCE/RPC server, the internal DNS server or     the Samba DLZ plugin for BIND9, if the     DSPROPERTY_ZONE_MASTER_SERVERS property or     DSPROPERTY_ZONE_SCAVENGING_SERVERS property is set, the     server will follow a NULL pointer and terminate. There     is no further vulnerability associated with this issue,     merely a denial of service.(CVE-2018-16852)

  - It was found that the 'bad password observation window'     was ineffective when set to a value greater than 3     minutes. This could allow for brute force password     attacks in some situations.(CVE-2018-16857)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Update to Samba 4.9.3

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The version of Samba running on the remote host is 4.7.x prior to 4.7.12, or 4.8.x prior to 4.8.7, or 4.9.x prior to 4.9.3. It is, therefore, affected by multiple vulnerabilities.

Notes: 
  - Refer to vendor advisories for possible workarounds.
  - CVE-2018-16852 and CVE-2018-16857 only apply to 4.9.x.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

New samba packages are available for Slackware 14.0, 14.1, 14.2, and
-current to fix security issues.

The samba project reports :

All versions of Samba from 4.0.0 onwards are vulnerable to infinite query recursion caused by CNAME loops. Any dns record can be added via ldap by an unprivileged user using the ldbadd tool, so this is a security issue.

When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ.

During the processing of an LDAP search before Samba's AD DC returns the LDAP entries to the client, the entries are cached in a single memory object with a maximum size of 256MB. When this size is reached, the Samba process providing the LDAP service will follow the NULL pointer, terminating the process.

During the processing of an DNS zone in the DNS management DCE/RPC server, the internal DNS server or the Samba DLZ plugin for BIND9, if the DSPROPERTY_ZONE_MASTER_SERVERS property or DSPROPERTY_ZONE_SCAVENGING_SERVERS property is set, the server will follow a NULL pointer and terminate

A user in a Samba AD domain can crash the KDC when Samba is built in the non-default MIT Kerberos configuration.

AD DC Configurations watching for bad passwords (to restrict brute forcing of passwords) in a window of more than 3 minutes may not watch for bad passwords at all.

ID	Name	Product	Family	Severity
134927	GLSA-202003-52 : Samba: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	critical
132794	EulerOS Virtualization for ARM 64 3.0.5.0 : samba (EulerOS-SA-2020-1040)	Nessus	Huawei Local Security Checks	critical
130825	EulerOS 2.0 SP8 : samba (EulerOS-SA-2019-2116)	Nessus	Huawei Local Security Checks	critical
120862	Fedora 29 : 2:samba (2018-e423e8743f)	Nessus	Fedora Local Security Checks	medium
119306	Samba 4.7.x < 4.7.12 / 4.8.x < 4.8.7 / 4.9.x < 4.9.3 Multiple Vulnerabilities	Nessus	Misc.	medium
119280	Slackware 14.0 / 14.1 / 14.2 / current : samba (SSA:2018-333-01)	Nessus	Slackware Local Security Checks	medium
119246	FreeBSD : samba -- multiple vulnerabilities (54976998-f248-11e8-81e2-005056a311d1)	Nessus	FreeBSD Local Security Checks	medium

Detections

Analytics

CVE-2018-16852

medium

Tenable Plugins

critical

critical

critical

medium

medium

medium

medium