ID CVE-2018-16853
Summary Samba from version 4.7.0 has a vulnerability that allows a user in a Samba AD domain to crash the KDC when Samba is built in the non-default MIT Kerberos configuration. With this advisory the Samba Team clarify that the MIT Kerberos build of the Samba AD DC is considered experimental. Therefore the Samba Team will not issue security patches for this configuration. Additionally, Samba 4.7.12, 4.8.7 and 4.9.3 have been issued as security releases to prevent building of the AD DC with MIT Kerberos unless --with-experimental-mit-ad-dc is specified to the configure command.
References
Vulnerable Configurations
  • Samba 4.7.0
    cpe:2.3:a:samba:samba:4.7.0
  • Samba 4.7.0 Release Candidate 1
    cpe:2.3:a:samba:samba:4.7.0:rc1
  • Samba 4.7.0 Release Candidate 2
    cpe:2.3:a:samba:samba:4.7.0:rc2
  • Samba 4.7.0 Release Candidate 3
    cpe:2.3:a:samba:samba:4.7.0:rc3
  • Samba 4.7.0 Release Candidate 4
    cpe:2.3:a:samba:samba:4.7.0:rc4
  • Samba 4.7.0 Release Candidate 5
    cpe:2.3:a:samba:samba:4.7.0:rc5
  • Samba 4.7.0 Release Candidate 6
    cpe:2.3:a:samba:samba:4.7.0:rc6
  • Samba 4.7.1
    cpe:2.3:a:samba:samba:4.7.1
  • Samba 4.7.2
    cpe:2.3:a:samba:samba:4.7.2
  • Samba 4.7.3
    cpe:2.3:a:samba:samba:4.7.3
  • Samba 4.7.4
    cpe:2.3:a:samba:samba:4.7.4
  • Samba 4.7.5
    cpe:2.3:a:samba:samba:4.7.5
  • Samba 4.7.6
    cpe:2.3:a:samba:samba:4.7.6
  • Samba 4.7.7
    cpe:2.3:a:samba:samba:4.7.7
  • Samba 4.7.8
    cpe:2.3:a:samba:samba:4.7.8
  • Samba 4.7.9
    cpe:2.3:a:samba:samba:4.7.9
  • Samba 4.7.10
    cpe:2.3:a:samba:samba:4.7.10
  • Samba 4.8.0
    cpe:2.3:a:samba:samba:4.8.0
  • Samba 4.8.0 Release Candidate 1
    cpe:2.3:a:samba:samba:4.8.0:rc1
  • Samba 4.8.0 Release Candidate 2
    cpe:2.3:a:samba:samba:4.8.0:rc2
  • Samba 4.8.0 Release Candidate 3
    cpe:2.3:a:samba:samba:4.8.0:rc3
  • Samba 4.8.0 Release Candidate 4
    cpe:2.3:a:samba:samba:4.8.0:rc4
  • Samba 4.8.1
    cpe:2.3:a:samba:samba:4.8.1
  • Samba 4.8.2
    cpe:2.3:a:samba:samba:4.8.2
  • Samba 4.8.3
    cpe:2.3:a:samba:samba:4.8.3
  • Samba 4.8.4
    cpe:2.3:a:samba:samba:4.8.4
  • Samba 4.8.5
    cpe:2.3:a:samba:samba:4.8.5
  • Samba 4.8.6
    cpe:2.3:a:samba:samba:4.8.6
  • Samba 4.9.0
    cpe:2.3:a:samba:samba:4.9.0
  • Samba 4.9.1
    cpe:2.3:a:samba:samba:4.9.1
CVSS
Base: 4.3
Impact:
Exploitability:
CWE CWE-400
CAPEC
  • XML Ping of the Death
    An attacker initiates a resource depletion attack where a large number of small XML messages are delivered at a sufficiently rapid rate to cause a denial of service or crash of the target. Transactions such as repetitive SOAP transactions can deplete resources faster than a simple flooding attack because of the additional resources used by the SOAP protocol and the resources necessary to process SOAP messages. The transactions used are immaterial as long as they cause resource utilization on the target. In other words, this is a normal flooding attack augmented by using messages that will require extra processing on the target.
  • XML Entity Expansion
    An attacker submits an XML document to a target application where the XML document uses nested entity expansion to produce an excessively large output XML. XML allows the definition of macro-like structures that can be used to simplify the creation of complex structures. However, this capability can be abused to create excessive demands on a processor's CPU and memory. A small number of nested expansions can result in an exponential growth in demands on memory.
  • Inducing Account Lockout
    An attacker leverages the security functionality of the system aimed at thwarting potential attacks to launch a denial of service attack against a legitimate system user. Many systems, for instance, implement a password throttling mechanism that locks an account after a certain number of incorrect log in attempts. An attacker can leverage this throttling mechanism to lock a legitimate user out of their own account. The weakness that is being leveraged by an attacker is the very security feature that has been put in place to counteract attacks.
  • Violating Implicit Assumptions Regarding XML Content (aka XML Denial of Service (XDoS))
    XML Denial of Service (XDoS) can be applied to any technology that utilizes XML data. This is, of course, most distributed systems technology including Java, .Net, databases, and so on. XDoS is most closely associated with web services, SOAP, and Rest, because remote service requesters can post malicious XML payloads to the service provider designed to exhaust the service provider's memory, CPU, and/or disk space. The main weakness in XDoS is that the service provider generally must inspect, parse, and validate the XML messages to determine routing, workflow, security considerations, and so on. It is exactly these inspection, parsing, and validation routines that XDoS targets. There are three primary attack vectors that XDoS can navigate Target CPU through recursion: attacker creates a recursive payload and sends to service provider Target memory through jumbo payloads: service provider uses DOM to parse XML. DOM creates in memory representation of XML document, but when document is very large (for example, north of 1 Gb) service provider host may exhaust memory trying to build memory objects. XML Ping of death: attack service provider with numerous small files that clog the system. All of the above attacks exploit the loosely coupled nature of web services, where the service provider has little to no control over the service requester and any messages the service requester sends.
nessus via4
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2018-4066-1.NASL
    description This update for samba fixes the following issues : Update to samba version 4.7.11. Security issues fixed : CVE-2018-14629: Fixed CNAME loops in Samba AD DC DNS server (bsc#1116319). CVE-2018-16841: Fixed segfault on PKINIT when mis-matching principal (bsc#1116320). CVE-2018-16851: Fixed NULL pointer de-reference in Samba AD DC LDAP server (bsc#1116322). CVE-2018-16853: Mark MIT support for the AD DC experimental (bsc#1116324). Non-security issues fixed: Fixed do not take over stderr when there is no log file (bsc#1101499). Fixed ctdb_mutex_ceph_rados_helper deadlock; (bsc#1102230). Fixed ntlm authentications with 'winbind use default domain = yes'; (bsc#1068059). Fixed idmap_rid to have primary group other than 'Domain Users'; (bsc#1087931). Fixed windows domain with one way trust that was not working (bsc#1087303). Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2019-02-05
    plugin id 120184
    published 2019-01-02
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=120184
    title SUSE SLED15 / SLES15 Security Update : samba (SUSE-SU-2018:4066-1)
  • NASL family FreeBSD Local Security Checks
    NASL id FREEBSD_PKG_54976998F24811E881E2005056A311D1.NASL
    description 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.
    last seen 2019-02-21
    modified 2019-02-05
    plugin id 119246
    published 2018-11-28
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=119246
    title FreeBSD : samba -- multiple vulnerabilities (54976998-f248-11e8-81e2-005056a311d1)
  • NASL family Slackware Local Security Checks
    NASL id SLACKWARE_SSA_2018-333-01.NASL
    description New samba packages are available for Slackware 14.0, 14.1, 14.2, and -current to fix security issues.
    last seen 2019-02-06
    modified 2019-02-05
    plugin id 119280
    published 2018-11-29
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=119280
    title Slackware 14.0 / 14.1 / 14.2 / current : samba (SSA:2018-333-01)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2018-C2A93F8E1B.NASL
    description Update to Samba 4.8.7 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.
    last seen 2019-02-21
    modified 2019-02-05
    plugin id 120763
    published 2019-01-03
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=120763
    title Fedora 28 : 2:samba (2018-c2a93f8e1b)
  • NASL family Misc.
    NASL id SAMBA_4_7_12.NASL
    description 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.
    last seen 2019-02-21
    modified 2018-11-30
    plugin id 119306
    published 2018-11-30
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=119306
    title Samba 4.7.x < 4.7.12 / 4.8.x < 4.8.7 / 4.9.x < 4.9.3 Multiple Vulnerabilities
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2018-E423E8743F.NASL
    description 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.
    last seen 2019-02-21
    modified 2019-02-05
    plugin id 120862
    published 2019-01-03
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=120862
    title Fedora 29 : 2:samba (2018-e423e8743f)
refmap via4
bid 106026
confirm
Last major update 28-11-2018 - 09:29
Published 28-11-2018 - 09:29
Last modified 04-02-2019 - 15:10
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