Vulnerabilities > CVE-2018-16853 - Resource Exhaustion vulnerability in Samba

047910
CVSS 5.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
HIGH
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
high complexity
samba
CWE-400
nessus

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.

Common Attack Pattern Enumeration and Classification (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

  • NASL familySlackware Local Security Checks
    NASL idSLACKWARE_SSA_2018-333-01.NASL
    descriptionNew samba packages are available for Slackware 14.0, 14.1, 14.2, and -current to fix security issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id119280
    published2018-11-29
    reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/119280
    titleSlackware 14.0 / 14.1 / 14.2 / current : samba (SSA:2018-333-01)
    code
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from Slackware Security Advisory 2018-333-01. The text 
    # itself is copyright (C) Slackware Linux, Inc.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(119280);
      script_version("1.4");
      script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/24");
    
      script_cve_id("CVE-2018-14629", "CVE-2018-16841", "CVE-2018-16851", "CVE-2018-16852", "CVE-2018-16853", "CVE-2018-16857");
      script_xref(name:"SSA", value:"2018-333-01");
    
      script_name(english:"Slackware 14.0 / 14.1 / 14.2 / current : samba (SSA:2018-333-01)");
      script_summary(english:"Checks for updated package in /var/log/packages");
    
      script_set_attribute(
        attribute:"synopsis",
        value:"The remote Slackware host is missing a security update."
      );
      script_set_attribute(
        attribute:"description",
        value:
    "New samba packages are available for Slackware 14.0, 14.1, 14.2, and
    -current to fix security issues."
      );
      # http://www.slackware.com/security/viewer.php?l=slackware-security&y=2018&m=slackware-security.507711
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?c18ee90c"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected samba package.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
      script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
      script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N");
      script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
      script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-16857");
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:slackware:slackware_linux:samba");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux:14.0");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux:14.1");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux:14.2");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2018/11/28");
      script_set_attribute(attribute:"patch_publication_date", value:"2018/11/29");
      script_set_attribute(attribute:"plugin_publication_date", value:"2018/11/29");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"Slackware Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/Slackware/release", "Host/Slackware/packages");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("global_settings.inc");
    include("slackware.inc");
    
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    if (!get_kb_item("Host/Slackware/release")) audit(AUDIT_OS_NOT, "Slackware");
    if (!get_kb_item("Host/Slackware/packages")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    
    cpu = get_kb_item("Host/cpu");
    if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
    if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "Slackware", cpu);
    
    
    flag = 0;
    if (slackware_check(osver:"14.0", pkgname:"samba", pkgver:"4.6.16", pkgarch:"i486", pkgnum:"2_slack14.0")) flag++;
    if (slackware_check(osver:"14.0", arch:"x86_64", pkgname:"samba", pkgver:"4.6.16", pkgarch:"x86_64", pkgnum:"2_slack14.0")) flag++;
    
    if (slackware_check(osver:"14.1", pkgname:"samba", pkgver:"4.6.16", pkgarch:"i486", pkgnum:"2_slack14.1")) flag++;
    if (slackware_check(osver:"14.1", arch:"x86_64", pkgname:"samba", pkgver:"4.6.16", pkgarch:"x86_64", pkgnum:"2_slack14.1")) flag++;
    
    if (slackware_check(osver:"14.2", pkgname:"samba", pkgver:"4.6.16", pkgarch:"i586", pkgnum:"2_slack14.2")) flag++;
    if (slackware_check(osver:"14.2", arch:"x86_64", pkgname:"samba", pkgver:"4.6.16", pkgarch:"x86_64", pkgnum:"2_slack14.2")) flag++;
    
    if (slackware_check(osver:"current", pkgname:"samba", pkgver:"4.9.3", pkgarch:"i586", pkgnum:"1")) flag++;
    if (slackware_check(osver:"current", arch:"x86_64", pkgname:"samba", pkgver:"4.9.3", pkgarch:"x86_64", pkgnum:"1")) flag++;
    
    
    if (flag)
    {
      if (report_verbosity > 0) security_warning(port:0, extra:slackware_report_get());
      else security_warning(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familyMisc.
    NASL idSAMBA_4_7_12.NASL
    descriptionThe 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
    last seen2020-06-01
    modified2020-06-02
    plugin id119306
    published2018-11-30
    reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/119306
    titleSamba 4.7.x < 4.7.12 / 4.8.x < 4.8.7 / 4.9.x < 4.9.3 Multiple Vulnerabilities
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2018-4066-1.NASL
    descriptionThis 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
    last seen2020-03-18
    modified2019-01-02
    plugin id120184
    published2019-01-02
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/120184
    titleSUSE SLED15 / SLES15 Security Update : samba (SUSE-SU-2018:4066-1)
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-202003-52.NASL
    descriptionThe 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.
    last seen2020-03-31
    modified2020-03-26
    plugin id134927
    published2020-03-26
    reporterThis script is Copyright (C) 2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/134927
    titleGLSA-202003-52 : Samba: Multiple vulnerabilities
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_54976998F24811E881E2005056A311D1.NASL
    descriptionThe 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
    last seen2020-06-01
    modified2020-06-02
    plugin id119246
    published2018-11-28
    reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/119246
    titleFreeBSD : samba -- multiple vulnerabilities (54976998-f248-11e8-81e2-005056a311d1)
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2018-C2A93F8E1B.NASL
    descriptionUpdate 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 seen2020-06-05
    modified2019-01-03
    plugin id120763
    published2019-01-03
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/120763
    titleFedora 28 : 2:samba (2018-c2a93f8e1b)
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2018-E423E8743F.NASL
    descriptionUpdate 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 seen2020-06-05
    modified2019-01-03
    plugin id120862
    published2019-01-03
    reporterThis script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/120862
    titleFedora 29 : 2:samba (2018-e423e8743f)