Vulnerabilities > CVE-2016-6171 - Resource Exhaustion vulnerability in Knot-Dns Knot DNS 2.1.1/2.2.0/2.2.1

047910
CVSS 8.6 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
HIGH
network
low complexity
knot-dns
CWE-400
nessus
NVD
Published: 2017-02-09
Updated: 2020-06-11

Summary

Knot DNS before 2.3.0 allows remote DNS servers to cause a denial of service (memory exhaustion and slave server crash) via a large zone transfer for (1) DDNS, (2) AXFR, or (3) IXFR.

Vulnerable Configurations

Part Description Count
Application
Knot-Dns
3

Common Weakness Enumeration (CWE)

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 familyFedora Local Security Checks
    NASL idFEDORA_2016-66C0C2105B.NASL
    descriptionfix build on big endian ---- new upstream release, security fix for CVE-2016-6171 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
    modified2016-08-22
    plugin id93057
    published2016-08-22
    reporterThis script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/93057
    titleFedora 23 : knot (2016-66c0c2105b)
    code
    #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2016-66c0c2105b.
#

include("compat.inc");

if (description)
{
  script_id(93057);
  script_version("2.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2016-6171");
  script_xref(name:"FEDORA", value:"2016-66c0c2105b");

  script_name(english:"Fedora 23 : knot (2016-66c0c2105b)");
  script_summary(english:"Checks rpm output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"fix build on big endian

----

new upstream release, security fix for CVE-2016-6171

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."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bodhi.fedoraproject.org/updates/FEDORA-2016-66c0c2105b"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected knot package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:knot");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:23");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/08/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/08/22");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^23([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 23", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) 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, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC23", reference:"knot-2.3.0-2.fc23")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "knot");
}
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_7D08E6085E9511E6B334002590263BF5.NASL
    descriptionISC reports : DNS protocols were designed with the assumption that a certain amount of trust could be presumed between the operators of primary and secondary servers for a given zone. However, in current practice some organizations have scenarios which require them to accept zone data from sources that are not fully trusted (for example: providers of secondary name service). A party who is allowed to feed data into a zone (e.g. by AXFR, IXFR, or Dynamic DNS updates) can overwhelm the server which is accepting data by intentionally or accidentally exhausting that server
    last seen2020-06-01
    modified2020-06-02
    plugin id92832
    published2016-08-10
    reporterThis script is Copyright (C) 2016-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/92832
    titleFreeBSD : BIND,Knot,NSD,PowerDNS -- denial over service via oversized zone transfers (7d08e608-5e95-11e6-b334-002590263bf5)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from the FreeBSD VuXML database :
#
# Copyright 2003-2018 Jacques Vidrine and contributors
#
# Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
# HTML, PDF, PostScript, RTF and so forth) with or without modification,
# are permitted provided that the following conditions are met:
# 1. Redistributions of source code (VuXML) must retain the above
#    copyright notice, this list of conditions and the following
#    disclaimer as the first lines of this file unmodified.
# 2. Redistributions in compiled form (transformed to other DTDs,
#    published online in any format, converted to PDF, PostScript,
#    RTF and other formats) must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer
#    in the documentation and/or other materials provided with the
#    distribution.
# 
# THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
# OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
# OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
# BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
# OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

include("compat.inc");

if (description)
{
  script_id(92832);
  script_version("2.9");
  script_cvs_date("Date: 2018/12/19 13:21:18");

  script_cve_id("CVE-2016-6170", "CVE-2016-6171", "CVE-2016-6172", "CVE-2016-6173");

  script_name(english:"FreeBSD : BIND,Knot,NSD,PowerDNS -- denial over service via oversized zone transfers (7d08e608-5e95-11e6-b334-002590263bf5)");
  script_summary(english:"Checks for updated packages in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote FreeBSD host is missing one or more security-related
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"ISC reports :

DNS protocols were designed with the assumption that a certain amount
of trust could be presumed between the operators of primary and
secondary servers for a given zone. However, in current practice some
organizations have scenarios which require them to accept zone data
from sources that are not fully trusted (for example: providers of
secondary name service). A party who is allowed to feed data into a
zone (e.g. by AXFR, IXFR, or Dynamic DNS updates) can overwhelm the
server which is accepting data by intentionally or accidentally
exhausting that server's memory."
  );
  # https://kb.isc.org/article/AA-01390
  script_set_attribute(
    attribute:"see_also",
    value:"https://kb.isc.org/docs/aa-01390"
  );
  # http://www.openwall.com/lists/oss-security/2016/07/06/4
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.openwall.com/lists/oss-security/2016/07/06/4"
  );
  # https://vuxml.freebsd.org/freebsd/7d08e608-5e95-11e6-b334-002590263bf5.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?302429c0"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:bind9-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:bind910");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:bind911");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:bind99");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:knot");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:knot1");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:knot2");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:nsd");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:powerdns");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2016/07/06");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/08/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/08/10");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"FreeBSD Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info");

  exit(0);
}


include("audit.inc");
include("freebsd_package.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);


flag = 0;

if (pkg_test(save_report:TRUE, pkg:"bind99<=9.9.9P2")) flag++;
if (pkg_test(save_report:TRUE, pkg:"bind910<=9.10.4P2")) flag++;
if (pkg_test(save_report:TRUE, pkg:"bind911<=9.11.0.b2")) flag++;
if (pkg_test(save_report:TRUE, pkg:"bind9-devel<=9.12.0.a.2016.11.02")) flag++;
if (pkg_test(save_report:TRUE, pkg:"knot<1.6.8")) flag++;
if (pkg_test(save_report:TRUE, pkg:"knot1<1.6.8")) flag++;
if (pkg_test(save_report:TRUE, pkg:"knot2<2.3.0")) flag++;
if (pkg_test(save_report:TRUE, pkg:"nsd<4.1.11")) flag++;
if (pkg_test(save_report:TRUE, pkg:"powerdns<4.0.1")) flag++;

if (flag)
{
  if (report_verbosity > 0) security_hole(port:0, extra:pkg_report_get());
  else security_hole(0);
  exit(0);
}
else audit(AUDIT_HOST_NOT, "affected");
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2016-3479F8E060.NASL
    descriptionfix build on big endian ---- new upstream release, security fix for CVE-2016-6171 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
    modified2016-08-22
    plugin id93055
    published2016-08-22
    reporterThis script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/93055
    titleFedora 24 : knot (2016-3479f8e060)
    code
    #%NASL_MIN_LEVEL 80502
#
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Fedora Security Advisory FEDORA-2016-3479f8e060.
#

include("compat.inc");

if (description)
{
  script_id(93055);
  script_version("2.5");
  script_set_attribute(attribute:"plugin_modification_date", value:"2020/06/04");

  script_cve_id("CVE-2016-6171");
  script_xref(name:"FEDORA", value:"2016-3479f8e060");

  script_name(english:"Fedora 24 : knot (2016-3479f8e060)");
  script_summary(english:"Checks rpm output for the updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Fedora host is missing a security update."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"fix build on big endian

----

new upstream release, security fix for CVE-2016-6171

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."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bodhi.fedoraproject.org/updates/FEDORA-2016-3479f8e060"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected knot package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:knot");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:24");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/02/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/08/19");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/08/22");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Fedora Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/RedHat/release", "Host/RedHat/rpm-list");

  exit(0);
}


include("audit.inc");
include("global_settings.inc");
include("rpm.inc");


if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/RedHat/release");
if (isnull(release) || "Fedora" >!< release) audit(AUDIT_OS_NOT, "Fedora");
os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Fedora");
os_ver = os_ver[1];
if (! preg(pattern:"^24([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, "Fedora 24", "Fedora " + os_ver);

if (!get_kb_item("Host/RedHat/rpm-list")) 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, "Fedora", cpu);


flag = 0;
if (rpm_check(release:"FC24", reference:"knot-2.3.0-2.fc24")) flag++;


if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "knot");
}
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2016-7F0FB9B38D.NASL
    descriptionfix build on big endian ---- new upstream release, security fix for CVE-2016-6171 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
    modified2016-11-15
    plugin id94824
    published2016-11-15
    reporterThis script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/94824
    titleFedora 25 : knot (2016-7f0fb9b38d)

References