Vulnerabilities > CVE-2016-9042 - Improper Input Validation vulnerability in multiple products

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
ntp
freebsd
hpe
siemens
CWE-20
nessus
NVD
Published: 2018-06-04
Updated: 2023-11-07

Summary

An exploitable denial of service vulnerability exists in the origin timestamp check functionality of ntpd 4.2.8p9. A specially crafted unauthenticated network packet can be used to reset the expected origin timestamp for target peers. Legitimate replies from targeted peers will fail the origin timestamp check (TEST2) causing the reply to be dropped and creating a denial of service condition.

Vulnerable Configurations

Part Description Count
Application
Ntp
1
Application
Hpe
6
OS
Freebsd
2
OS
Siemens
1
Hardware
Siemens
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Nessus

  • NASL familySlackware Local Security Checks
    NASL idSLACKWARE_SSA_2017-112-02.NASL
    descriptionNew ntp packages are available for Slackware 13.0, 13.1, 13.37, 14.0, 14.1, 14.2, and -current to fix security issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id99597
    published2017-04-24
    reporterThis script is Copyright (C) 2017-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/99597
    titleSlackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : ntp (SSA:2017-112-02)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were  
# extracted from Slackware Security Advisory 2017-112-02. The text 
# itself is copyright (C) Slackware Linux, Inc.
#

include("compat.inc");

if (description)
{
  script_id(99597);
  script_version("$Revision: 3.4 $");
  script_cvs_date("$Date: 2018/01/26 17:50:31 $");

  script_cve_id("CVE-2016-9042", "CVE-2017-6451", "CVE-2017-6452", "CVE-2017-6455", "CVE-2017-6458", "CVE-2017-6459", "CVE-2017-6460", "CVE-2017-6462", "CVE-2017-6463", "CVE-2017-6464");
  script_xref(name:"SSA", value:"2017-112-02");

  script_name(english:"Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : ntp (SSA:2017-112-02)");
  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 ntp packages are available for Slackware 13.0, 13.1, 13.37, 14.0,
14.1, 14.2, and -current to fix security issues."
  );
  # http://www.slackware.com/security/viewer.php?l=slackware-security&y=2017&m=slackware-security.648848
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?7a77564e"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected ntp package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:slackware:slackware_linux:ntp");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux:13.1");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:slackware:slackware_linux:13.37");
  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:"patch_publication_date", value:"2017/04/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/04/24");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2018 Tenable Network Security, Inc.");
  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:"13.0", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i486", pkgnum:"1_slack13.0")) flag++;
if (slackware_check(osver:"13.0", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"x86_64", pkgnum:"1_slack13.0")) flag++;

if (slackware_check(osver:"13.1", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i486", pkgnum:"1_slack13.1")) flag++;
if (slackware_check(osver:"13.1", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"x86_64", pkgnum:"1_slack13.1")) flag++;

if (slackware_check(osver:"13.37", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i486", pkgnum:"1_slack13.37")) flag++;
if (slackware_check(osver:"13.37", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"x86_64", pkgnum:"1_slack13.37")) flag++;

if (slackware_check(osver:"14.0", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i486", pkgnum:"1_slack14.0")) flag++;
if (slackware_check(osver:"14.0", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"x86_64", pkgnum:"1_slack14.0")) flag++;

if (slackware_check(osver:"14.1", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i486", pkgnum:"1_slack14.1")) flag++;
if (slackware_check(osver:"14.1", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"x86_64", pkgnum:"1_slack14.1")) flag++;

if (slackware_check(osver:"14.2", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i586", pkgnum:"1_slack14.2")) flag++;
if (slackware_check(osver:"14.2", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"x86_64", pkgnum:"1_slack14.2")) flag++;

if (slackware_check(osver:"current", pkgname:"ntp", pkgver:"4.2.8p10", pkgarch:"i586", pkgnum:"1")) flag++;
if (slackware_check(osver:"current", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p10", 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 familySuSE Local Security Checks
    NASL idSUSE_SU-2017-1052-1.NASL
    descriptionThis ntp update to version 4.2.8p10 fixes the following issues: Security issues fixed (bsc#1030050) : - CVE-2017-6464: Denial of Service via Malformed Config - CVE-2017-6462: Buffer Overflow in DPTS Clock - CVE-2017-6463: Authenticated DoS via Malicious Config Option - CVE-2017-6458: Potential Overflows in ctl_put() functions - CVE-2017-6451: Improper use of snprintf() in mx4200_send() - CVE-2017-6460: Buffer Overflow in ntpq when fetching reslist - CVE-2016-9042: 0rigin (zero origin) DoS. - ntpq_stripquotes() returns incorrect Value - ereallocarray()/eallocarray() underused - Copious amounts of Unused Code - Off-by-one in Oncore GPS Receiver - Makefile does not enforce Security Flags Bugfixes : - Remove spurious log messages (bsc#1014172). - Fixing ppc and ppc64 linker issue (bsc#1031085). - clang scan-build findings - Support for openssl-1.1.0 without compatibility modes - Bugfix 3072 breaks multicastclient - forking async worker: interrupted pipe I/O - (...) time_pps_create: Exec format error - Incorrect Logic for Peer Event Limiting - Change the process name of forked DNS worker - Trap Configuration Fail - Nothing happens if minsane - allow -4/-6 on restrict line with mask - out-of-bound pointers in ctl_putsys and decode_bitflags - Move ntp-kod to /var/lib/ntp, because /var/db is not a standard directory and causes problems for transactional updates. 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 seen2020-06-01
    modified2020-06-02
    plugin id99469
    published2017-04-19
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99469
    titleSUSE SLES11 Security Update : ntp (SUSE-SU-2017:1052-1)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from SUSE update advisory SUSE-SU-2017:1052-1.
# The text itself is copyright (C) SUSE.
#

include("compat.inc");

if (description)
{
  script_id(99469);
  script_version("3.12");
  script_cvs_date("Date: 2019/09/11 11:22:15");

  script_cve_id("CVE-2016-9042", "CVE-2017-6451", "CVE-2017-6458", "CVE-2017-6460", "CVE-2017-6462", "CVE-2017-6463", "CVE-2017-6464");

  script_name(english:"SUSE SLES11 Security Update : ntp (SUSE-SU-2017:1052-1)");
  script_summary(english:"Checks rpm output for the updated packages.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote SUSE host is missing one or more security updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"This ntp update to version 4.2.8p10 fixes the following issues:
Security issues fixed (bsc#1030050) :

  - CVE-2017-6464: Denial of Service via Malformed Config

  - CVE-2017-6462: Buffer Overflow in DPTS Clock

  - CVE-2017-6463: Authenticated DoS via Malicious Config
    Option

  - CVE-2017-6458: Potential Overflows in ctl_put()
    functions

  - CVE-2017-6451: Improper use of snprintf() in
    mx4200_send()

  - CVE-2017-6460: Buffer Overflow in ntpq when fetching
    reslist

  - CVE-2016-9042: 0rigin (zero origin) DoS.

  - ntpq_stripquotes() returns incorrect Value

  - ereallocarray()/eallocarray() underused

  - Copious amounts of Unused Code

  - Off-by-one in Oncore GPS Receiver

  - Makefile does not enforce Security Flags Bugfixes :

  - Remove spurious log messages (bsc#1014172).

  - Fixing ppc and ppc64 linker issue (bsc#1031085).

  - clang scan-build findings

  - Support for openssl-1.1.0 without compatibility modes

  - Bugfix 3072 breaks multicastclient

  - forking async worker: interrupted pipe I/O

  - (...) time_pps_create: Exec format error

  - Incorrect Logic for Peer Event Limiting

  - Change the process name of forked DNS worker

  - Trap Configuration Fail

  - Nothing happens if minsane 

  - allow -4/-6 on restrict line with mask

  - out-of-bound pointers in ctl_putsys and decode_bitflags

  - Move ntp-kod to /var/lib/ntp, because /var/db is not a
    standard directory and causes problems for transactional
    updates.

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."
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.suse.com/show_bug.cgi?id=1014172"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.suse.com/show_bug.cgi?id=1030050"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://bugzilla.suse.com/show_bug.cgi?id=1031085"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2016-9042/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2017-6451/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2017-6458/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2017-6460/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2017-6462/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2017-6463/"
  );
  script_set_attribute(
    attribute:"see_also",
    value:"https://www.suse.com/security/cve/CVE-2017-6464/"
  );
  # https://www.suse.com/support/update/announcement/2017/suse-su-20171052-1/
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?1dfa73fc"
  );
  script_set_attribute(
    attribute:"solution", 
    value:
"To install this SUSE Security Update use YaST online_update.
Alternatively you can run the command listed for your product :

SUSE Linux Enterprise Server 11-SP4:zypper in -t patch
slessp4-ntp-13066=1

SUSE Linux Enterprise Debuginfo 11-SP4:zypper in -t patch
dbgsp4-ntp-13066=1

To bring your system up-to-date, use 'zypper patch'."
  );
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:ntp");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:suse_linux:ntp-doc");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:suse_linux:11");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/03/27");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/04/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/04/19");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"SuSE Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/SuSE/release", "Host/SuSE/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/SuSE/release");
if (isnull(release) || release !~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "SUSE");
os_ver = pregmatch(pattern: "^(SLE(S|D)\d+)", string:release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "SUSE");
os_ver = os_ver[1];
if (! preg(pattern:"^(SLES11)$", string:os_ver)) audit(AUDIT_OS_NOT, "SUSE SLES11", "SUSE " + os_ver);

if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if (cpu !~ "^i[3-6]86$" && "x86_64" >!< cpu && "s390x" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "SUSE " + os_ver, cpu);

sp = get_kb_item("Host/SuSE/patchlevel");
if (isnull(sp)) sp = "0";
if (os_ver == "SLES11" && (! preg(pattern:"^(4)$", string:sp))) audit(AUDIT_OS_NOT, "SLES11 SP4", os_ver + " SP" + sp);


flag = 0;
if (rpm_check(release:"SLES11", sp:"4", reference:"ntp-4.2.8p10-63.1")) flag++;
if (rpm_check(release:"SLES11", sp:"4", reference:"ntp-doc-4.2.8p10-63.1")) flag++;


if (flag)
{
  if (report_verbosity > 0) security_warning(port:0, extra:rpm_report_get());
  else security_warning(0);
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "ntp");
}
  • NASL familyUbuntu Local Security Checks
    NASL idUBUNTU_USN-3349-1.NASL
    descriptionYihan Lian discovered that NTP incorrectly handled certain large request data values. A remote attacker could possibly use this issue to cause NTP to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS. (CVE-2016-2519) Miroslav Lichvar discovered that NTP incorrectly handled certain spoofed addresses when performing rate limiting. A remote attacker could possibly use this issue to perform a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-7426) Matthew Van Gundy discovered that NTP incorrectly handled certain crafted broadcast mode packets. A remote attacker could possibly use this issue to perform a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-7427, CVE-2016-7428) Miroslav Lichvar discovered that NTP incorrectly handled certain responses. A remote attacker could possibly use this issue to perform a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-7429) Sharon Goldberg and Aanchal Malhotra discovered that NTP incorrectly handled origin timestamps of zero. A remote attacker could possibly use this issue to bypass the origin timestamp protection mechanism. This issue only affected Ubuntu 16.10. (CVE-2016-7431) Brian Utterback, Sharon Goldberg and Aanchal Malhotra discovered that NTP incorrectly performed initial sync calculations. This issue only applied to Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-7433) Magnus Stubman discovered that NTP incorrectly handled certain mrulist queries. A remote attacker could possibly use this issue to cause NTP to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-7434) Matthew Van Gund discovered that NTP incorrectly handled origin timestamp checks. A remote attacker could possibly use this issue to perform a denial of service. This issue only affected Ubuntu Ubuntu 16.10, and Ubuntu 17.04. (CVE-2016-9042) Matthew Van Gundy discovered that NTP incorrectly handled certain control mode packets. A remote attacker could use this issue to set or unset traps. This issue only applied to Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-9310) Matthew Van Gundy discovered that NTP incorrectly handled the trap service. A remote attacker could possibly use this issue to cause NTP to crash, resulting in a denial of service. This issue only applied to Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-9311) It was discovered that NTP incorrectly handled memory when processing long variables. A remote authenticated user could possibly use this issue to cause NTP to crash, resulting in a denial of service. (CVE-2017-6458) It was discovered that NTP incorrectly handled memory when processing long variables. A remote authenticated user could possibly use this issue to cause NTP to crash, resulting in a denial of service. This issue only applied to Ubuntu 16.04 LTS, Ubuntu 16.10 and Ubuntu 17.04. (CVE-2017-6460) It was discovered that the NTP legacy DPTS refclock driver incorrectly handled the /dev/datum device. A local attacker could possibly use this issue to cause a denial of service. (CVE-2017-6462) It was discovered that NTP incorrectly handled certain invalid settings in a :config directive. A remote authenticated user could possibly use this issue to cause NTP to crash, resulting in a denial of service. (CVE-2017-6463) It was discovered that NTP incorrectly handled certain invalid mode configuration directives. A remote authenticated user could possibly use this issue to cause NTP to crash, resulting in a denial of service. (CVE-2017-6464). Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen2020-06-01
    modified2020-06-02
    plugin id101263
    published2017-07-06
    reporterUbuntu Security Notice (C) 2017-2019 Canonical, Inc. / NASL script (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/101263
    titleUbuntu 14.04 LTS / 16.04 LTS / 16.10 / 17.04 : ntp vulnerabilities (USN-3349-1)
    code
    #
# (C) Tenable Network Security, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Ubuntu Security Notice USN-3349-1. The text 
# itself is copyright (C) Canonical, Inc. See 
# <http://www.ubuntu.com/usn/>. Ubuntu(R) is a registered 
# trademark of Canonical, Inc.
#

include("compat.inc");

if (description)
{
  script_id(101263);
  script_version("3.9");
  script_cvs_date("Date: 2019/09/18 12:31:47");

  script_cve_id("CVE-2016-2519", "CVE-2016-7426", "CVE-2016-7427", "CVE-2016-7428", "CVE-2016-7429", "CVE-2016-7431", "CVE-2016-7433", "CVE-2016-7434", "CVE-2016-9042", "CVE-2016-9310", "CVE-2016-9311", "CVE-2017-6458", "CVE-2017-6460", "CVE-2017-6462", "CVE-2017-6463", "CVE-2017-6464");
  script_xref(name:"USN", value:"3349-1");

  script_name(english:"Ubuntu 14.04 LTS / 16.04 LTS / 16.10 / 17.04 : ntp vulnerabilities (USN-3349-1)");
  script_summary(english:"Checks dpkg output for updated package.");

  script_set_attribute(
    attribute:"synopsis", 
    value:"The remote Ubuntu host is missing a security-related patch."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"Yihan Lian discovered that NTP incorrectly handled certain large
request data values. A remote attacker could possibly use this issue
to cause NTP to crash, resulting in a denial of service. This issue
only affected Ubuntu 16.04 LTS. (CVE-2016-2519)

Miroslav Lichvar discovered that NTP incorrectly handled certain
spoofed addresses when performing rate limiting. A remote attacker
could possibly use this issue to perform a denial of service. This
issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu
16.10. (CVE-2016-7426)

Matthew Van Gundy discovered that NTP incorrectly handled certain
crafted broadcast mode packets. A remote attacker could possibly use
this issue to perform a denial of service. This issue only affected
Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, and Ubuntu 16.10. (CVE-2016-7427,
CVE-2016-7428)

Miroslav Lichvar discovered that NTP incorrectly handled certain
responses. A remote attacker could possibly use this issue to perform
a denial of service. This issue only affected Ubuntu 14.04 LTS, Ubuntu
16.04 LTS, and Ubuntu 16.10. (CVE-2016-7429)

Sharon Goldberg and Aanchal Malhotra discovered that NTP incorrectly
handled origin timestamps of zero. A remote attacker could possibly
use this issue to bypass the origin timestamp protection mechanism.
This issue only affected Ubuntu 16.10. (CVE-2016-7431)

Brian Utterback, Sharon Goldberg and Aanchal Malhotra discovered that
NTP incorrectly performed initial sync calculations. This issue only
applied to Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-7433)

Magnus Stubman discovered that NTP incorrectly handled certain mrulist
queries. A remote attacker could possibly use this issue to cause NTP
to crash, resulting in a denial of service. This issue only affected
Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-7434)

Matthew Van Gund discovered that NTP incorrectly handled origin
timestamp checks. A remote attacker could possibly use this issue to
perform a denial of service. This issue only affected Ubuntu Ubuntu
16.10, and Ubuntu 17.04. (CVE-2016-9042)

Matthew Van Gundy discovered that NTP incorrectly handled certain
control mode packets. A remote attacker could use this issue to set or
unset traps. This issue only applied to Ubuntu 14.04 LTS, Ubuntu 16.04
LTS and Ubuntu 16.10. (CVE-2016-9310)

Matthew Van Gundy discovered that NTP incorrectly handled the trap
service. A remote attacker could possibly use this issue to cause NTP
to crash, resulting in a denial of service. This issue only applied to
Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2016-9311)

It was discovered that NTP incorrectly handled memory when processing
long variables. A remote authenticated user could possibly use this
issue to cause NTP to crash, resulting in a denial of service.
(CVE-2017-6458)

It was discovered that NTP incorrectly handled memory when processing
long variables. A remote authenticated user could possibly use this
issue to cause NTP to crash, resulting in a denial of service. This
issue only applied to Ubuntu 16.04 LTS, Ubuntu 16.10 and Ubuntu 17.04.
(CVE-2017-6460)

It was discovered that the NTP legacy DPTS refclock driver incorrectly
handled the /dev/datum device. A local attacker could possibly use
this issue to cause a denial of service. (CVE-2017-6462)

It was discovered that NTP incorrectly handled certain invalid
settings in a :config directive. A remote authenticated user could
possibly use this issue to cause NTP to crash, resulting in a denial
of service. (CVE-2017-6463)

It was discovered that NTP incorrectly handled certain invalid mode
configuration directives. A remote authenticated user could possibly
use this issue to cause NTP to crash, resulting in a denial of
service. (CVE-2017-6464).

Note that Tenable Network Security has extracted the preceding
description block directly from the Ubuntu security advisory. 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://usn.ubuntu.com/3349-1/"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected ntp package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:ntp");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:14.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.10");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:17.04");

  script_set_attribute(attribute:"vuln_publication_date", value:"2017/01/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2017/07/05");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/07/06");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"Ubuntu Security Notice (C) 2017-2019 Canonical, Inc. / NASL script (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
  script_family(english:"Ubuntu Local Security Checks");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}


include("audit.inc");
include("ubuntu.inc");
include("misc_func.inc");

if ( ! get_kb_item("Host/local_checks_enabled") ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
release = get_kb_item("Host/Ubuntu/release");
if ( isnull(release) ) audit(AUDIT_OS_NOT, "Ubuntu");
release = chomp(release);
if (! preg(pattern:"^(14\.04|16\.04|16\.10|17\.04)$", string:release)) audit(AUDIT_OS_NOT, "Ubuntu 14.04 / 16.04 / 16.10 / 17.04", "Ubuntu " + release);
if ( ! get_kb_item("Host/Debian/dpkg-l") ) 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, "Ubuntu", cpu);

flag = 0;

if (ubuntu_check(osver:"14.04", pkgname:"ntp", pkgver:"1:4.2.6.p5+dfsg-3ubuntu2.14.04.11")) flag++;
if (ubuntu_check(osver:"16.04", pkgname:"ntp", pkgver:"1:4.2.8p4+dfsg-3ubuntu5.5")) flag++;
if (ubuntu_check(osver:"16.10", pkgname:"ntp", pkgver:"1:4.2.8p8+dfsg-1ubuntu2.1")) flag++;
if (ubuntu_check(osver:"17.04", pkgname:"ntp", pkgver:"1:4.2.8p9+dfsg-2ubuntu1.1")) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_HOLE,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "ntp");
}
  • NASL familyMisc.
    NASL idNTP_4_2_8P10.NASL
    descriptionThe version of the remote NTP server is 4.x prior to 4.2.8p10. It is, therefore, affected by the following vulnerabilities : - A denial of service vulnerability exists in the receive() function within file ntpd/ntp_proto.c due to the expected origin timestamp being cleared when a packet with a zero origin timestamp is received. An unauthenticated, remote attacker can exploit this issue, via specially crafted network packets, to reset the expected origin timestamp for a target peer, resulting in legitimate replies being dropped. (CVE-2016-9042) - An out-of-bounds write error exists in the mx4200_send() function within file ntpd/refclock_mx4200.c due to improper handling of the return value of the snprintf() and vsnprintf() functions. An unauthenticated, remote attacker can exploit this to cause a denial of service condition or possibly the execution of arbitrary code. However, neither the researcher nor vendor could find any exploitable code path. (CVE-2017-6451) - A stack-based buffer overflow condition exists in the addSourceToRegistry() function within file ports/winnt/instsrv/instsrv.c due to improper validation of certain input when adding registry keys. A local attacker can exploit this to execute arbitrary code. (CVE-2017-6452) - A flaw exists due to dynamic link library (DLL) files being preloaded when they are defined in the inherited environment variable
    last seen2020-06-01
    modified2020-06-02
    plugin id97988
    published2017-03-27
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/97988
    titleNetwork Time Protocol Daemon (ntpd) 4.x < 4.2.8p10 Multiple Vulnerabilities
  • NASL familyMacOS X Local Security Checks
    NASL idMACOS_10_13.NASL
    descriptionThe remote host is running a version of Mac OS X that is prior to 10.10.5, 10.11.x prior to 10.11.6, 10.12.x prior to 10.12.6, or is not macOS 10.13. It is, therefore, affected by multiple vulnerabilities in the following components : - apache - AppSandbox - AppleScript - Application Firewall - ATS - Audio - CFNetwork - CFNetwork Proxies - CFString - Captive Network Assistant - CoreAudio - CoreText - DesktopServices - Directory Utility - file - Fonts - fsck_msdos - HFS - Heimdal - HelpViewer - IOFireWireFamily - ImageIO - Installer - Kernel - kext tools - libarchive - libc - libexpat - Mail - Mail Drafts - ntp - Open Scripting Architecture - PCRE - Postfix - Quick Look - QuickTime - Remote Management - SQLite - Sandbox - Screen Lock - Security - Spotlight - WebKit - zlib Note that successful exploitation of the most serious issues can result in arbitrary code execution.
    last seen2020-06-01
    modified2020-06-02
    plugin id103598
    published2017-10-03
    reporterThis script is Copyright (C) 2017-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/103598
    titlemacOS < 10.13 Multiple Vulnerabilities
  • NASL familyFedora Local Security Checks
    NASL idFEDORA_2017-20D54B2782.NASL
    descriptionSecurity fix for CVE-2017-6464 CVE-2017-6462 CVE-2017-6463 CVE-2017-6458 CVE-2017-6451 CVE-2017-6460 CVE-2016-9042. ---- This update improves the default configuration file to use the pool directive. It also replaces the ntpstat program with a shell script that uses the ntpq program instead of implementing the mode 6 protocol. 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
    modified2017-07-17
    plugin id101588
    published2017-07-17
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/101588
    titleFedora 26 : ntp (2017-20d54b2782)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2017-1048-1.NASL
    descriptionThis ntp update to version 4.2.8p10 fixes serveral issues. This updated enables leap smearing. See /usr/share/doc/packages/ntp/README.leapsmear for details. Security issues fixed (bsc#1030050) : - CVE-2017-6464: Denial of Service via Malformed Config - CVE-2017-6462: Buffer Overflow in DPTS Clock - CVE-2017-6463: Authenticated DoS via Malicious Config Option - CVE-2017-6458: Potential Overflows in ctl_put() functions - CVE-2017-6451: Improper use of snprintf() in mx4200_send() - CVE-2017-6460: Buffer Overflow in ntpq when fetching reslist - CVE-2016-9042: 0rigin (zero origin) DoS. - ntpq_stripquotes() returns incorrect Value - ereallocarray()/eallocarray() underused - Copious amounts of Unused Code - Off-by-one in Oncore GPS Receiver - Makefile does not enforce Security Flags Bugfixes : - Remove spurious log messages (bsc#1014172). - clang scan-build findings - Support for openssl-1.1.0 without compatibility modes - Bugfix 3072 breaks multicastclient - forking async worker: interrupted pipe I/O - (...) time_pps_create: Exec format error - Incorrect Logic for Peer Event Limiting - Change the process name of forked DNS worker - Trap Configuration Fail - Nothing happens if minsane - allow -4/-6 on restrict line with mask - out-of-bound pointers in ctl_putsys and decode_bitflags - Move ntp-kod to /var/lib/ntp, because /var/db is not a standard directory and causes problems for transactional updates. 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 seen2020-06-01
    modified2020-06-02
    plugin id99468
    published2017-04-19
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99468
    titleSUSE SLED12 / SLES12 Security Update : ntp (SUSE-SU-2017:1048-1)
  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_3C0237F5420E11E782C514DAE9D210B8.NASL
    descriptionA vulnerability was discovered in the NTP server
    last seen2020-06-01
    modified2020-06-02
    plugin id100496
    published2017-05-30
    reporterThis script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/100496
    titleFreeBSD : FreeBSD -- Multiple vulnerabilities of ntp (3c0237f5-420e-11e7-82c5-14dae9d210b8)
  • NASL familySuSE Local Security Checks
    NASL idOPENSUSE-2017-511.NASL
    descriptionThis ntp update to version 4.2.8p10 fixes serveral issues. This updated enables leap smearing. See /usr/share/doc/packages/ntp/README.leapsmear for details. Security issues fixed (bsc#1030050) : - CVE-2017-6464: Denial of Service via Malformed Config - CVE-2017-6462: Buffer Overflow in DPTS Clock - CVE-2017-6463: Authenticated DoS via Malicious Config Option - CVE-2017-6458: Potential Overflows in ctl_put() functions - CVE-2017-6451: Improper use of snprintf() in mx4200_send() - CVE-2017-6460: Buffer Overflow in ntpq when fetching reslist - CVE-2016-9042: 0rigin (zero origin) DoS. - ntpq_stripquotes() returns incorrect Value - ereallocarray()/eallocarray() underused - Copious amounts of Unused Code - Off-by-one in Oncore GPS Receiver - Makefile does not enforce Security Flags Bugfixes : - Remove spurious log messages (bsc#1014172). - clang scan-build findings - Support for openssl-1.1.0 without compatibility modes - Bugfix 3072 breaks multicastclient - forking async worker: interrupted pipe I/O - (...) time_pps_create: Exec format error - Incorrect Logic for Peer Event Limiting - Change the process name of forked DNS worker - Trap Configuration Fail - Nothing happens if minsane < maxclock < minclock - allow -4/-6 on restrict line with mask - out-of-bound pointers in ctl_putsys and decode_bitflags - Move ntp-kod to /var/lib/ntp, because /var/db is not a standard directory and causes problems for transactional updates. This update was imported from the SUSE:SLE-12-SP1:Update update project.
    last seen2020-06-05
    modified2017-04-27
    plugin id99700
    published2017-04-27
    reporterThis script is Copyright (C) 2017-2020 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99700
    titleopenSUSE Security Update : ntp (openSUSE-2017-511)
  • NASL familySuSE Local Security Checks
    NASL idSUSE_SU-2017-1047-1.NASL
    descriptionThis ntp update to version 4.2.8p10 fixes serveral issues. This updated enables leap smearing. See /usr/share/doc/packages/ntp/README.leapsmear for details. Security issues fixed (bsc#1030050) : - CVE-2017-6464: Denial of Service via Malformed Config - CVE-2017-6462: Buffer Overflow in DPTS Clock - CVE-2017-6463: Authenticated DoS via Malicious Config Option - CVE-2017-6458: Potential Overflows in ctl_put() functions - CVE-2017-6451: Improper use of snprintf() in mx4200_send() - CVE-2017-6460: Buffer Overflow in ntpq when fetching reslist - CVE-2016-9042: 0rigin (zero origin) DoS. - ntpq_stripquotes() returns incorrect Value - ereallocarray()/eallocarray() underused - Copious amounts of Unused Code - Off-by-one in Oncore GPS Receiver - Makefile does not enforce Security Flags Bugfixes : - Remove spurious log messages (bsc#1014172). - clang scan-build findings - Support for openssl-1.1.0 without compatibility modes - Bugfix 3072 breaks multicastclient - forking async worker: interrupted pipe I/O - (...) time_pps_create: Exec format error - Incorrect Logic for Peer Event Limiting - Change the process name of forked DNS worker - Trap Configuration Fail - Nothing happens if minsane - allow -4/-6 on restrict line with mask - out-of-bound pointers in ctl_putsys and decode_bitflags - Move ntp-kod to /var/lib/ntp, because /var/db is not a standard directory and causes problems for transactional updates. 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 seen2020-06-01
    modified2020-06-02
    plugin id99467
    published2017-04-19
    reporterThis script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/99467
    titleSUSE SLES12 Security Update : ntp (SUSE-SU-2017:1047-1)
  • NASL familyFirewalls
    NASL idPFSENSE_SA-17_04.NASL
    descriptionAccording to its self-reported version number, the remote pfSense install is affected by multiple vulnerabilities as stated in the referenced vendor advisories.
    last seen2020-06-01
    modified2020-06-02
    plugin id106504
    published2018-01-31
    reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/106504
    titlepfSense < 2.3.4 Multiple Vulnerabilities (SA-17_04)

Seebug

bulletinFamilyexploit
description### Summary An exploitable denial of service vulnerability exists in the origin timestamp check functionality of ntpd 4.2.8p9. A specially crafted unauthenticated network packet can be used to reset the expected origin timestamp for target peers. Legitimate replies from targeted peers will fail the origin timestamp check (TEST2) causing the reply to be dropped and creating a denial of service condition. ### Tested Versions NTP 4.2.8p9 ### Product URLs http://www.ntp.org ### CVSSv3 Score CVSSv2: 4.3 - (AV:N/AC:M/Au:N/C:N/I:N/A:P) CVSSv3: 3.7 - CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L ### Details In most modes, NTP prevents spoofing by off-path attackers by verifying that the origin timestamp of an incoming NTP packet matches the transmit timestamp on the daemon's last outgoing packet --- using the transmit and origin timestamps as a per-request nonce. This test described in RFC 5905 and dubbed TEST2 in ntpd's source code. To prevent an NTP daemon from accepting responses to duplicated request packets, RFC 5095 also specifies that the expected origin timestamp should be set to zero after successfully validating the origin timestamp of an incoming packet. Unfortunately, ntpd releases before 4.2.8p9 did not correctly reject incoming packets bearing a zero origin timestamp. This allowed a trivial bypass of TEST2, the origin timestamp check, by setting the origin timestamp on spoofed packets equal to zero (CVE-2015-8138,CVE-2016-7431). ntp-4.2.8p9 fixes CVE-2015-8138 by rejecting packets with zero origin timestamps in all modes where that is not expected legitimate behavior. However, for reasons unknown, before rejecting a packet bearing a zero origin timestamp, ntp-4.2.8p9 clears the expected origin timestamp (peer->aorg) as can be seen in the following abstracted code: ``` if (0) { } else if (L_ISZERO(&p_org)) { char *action; L_CLR(&peer->aorg); ... peer->bogusorg++; peer->flash |= TEST2; /* bogus */ ... /* packet will be dropped */ } else if (!L_ISEQU(&p_org, &peer->aorg)) { peer->bogusorg++; peer->flash |= TEST2; /* bogus */ ... /* packet will be dropped */ } else { L_CLR(&peer->aorg); } ``` This leads to a trivial denial of service. An unauthenticated network attacker who knows the address of one of the peers of a victim ntpd process can send the victim ntpd spoofed packets with the source address of the peer and a zero origin timestamp in order to reset peer->aorg for that peer. This will cause the next packet sent from the peer to fail the origin timestamp check (TEST2) and be dropped. The attacker can repeat this each poll period for all known peers in order to prevent their packets from being accepted by the victim ntpd. This attack is very effective against symmetric associations where the duration between an outgoing packet from the victim ntpd and its "response" will be on the order of seconds to minutes. The attack is more difficult for client-server associations where the request-response window is likely to be on the order of milliseconds. However, if the attacker can observe the victim ntpd's request packet, it can attempt to race the remote peer's legitimate response. An attacker can learn the currently selected peer of a victim ntpd process by sending the victim a client mode request and reading the peer's address from the refid field of the victim's response. This allows the attacker to target the currently selected peer one at a time until it has learned and targeted all peers of the victim ntpd process. If the victim allows NTP control queries or the attacker can observe the victim's NTP traffic, the attacker can easily learn all the victim's peers. The call to LCLR(&peer->aorg) when a zero-origin timestamp packet is received appears unnecessary and should be removed. To see that clearing peer->aorg is unnecessary, let's consider the operation of each NTP mode in turn after omitting the LCLR(&peer->aorg): * Client-Server: Servers are stateless, so the change has no effect on them. Clients should not be sending requests with zero transmit timestamps and, therefore, should not be receiving responses with zero origin timestamps. Thus, removing the L_CLR(&peer->aorg) should have no effect on legitimate client-server behavior. * Broadcast: Broadcast packets are handled separately and thus are not influenced by the behavior of this code. * Symmetric (Active and Passive): When two symmetric peers are synchronized to a legitimate time source (0 < stratum < 16) and the association between them is fully operational, the origin timestamp on incoming packets will be non-zero and equal to peer->aorg, thus avoiding the L_CLR(&peer->aorg). The interesting cases occur when there is packet loss or one peer resets their association (e.g. ntpd is restarted). Without loss of generality, let A be the sender and B the recipient of the first packet with pkt->org != peer->aorg. If A reset its association with B, pkt->org == 0. Otherwise, pkt->org != 0 && pkt->org != peer->aorg. In either case, B will mark the packet as having failed TEST2. However, if the packet is authenticated correctly for the association, B will update peer->xmt = pkt->xmt before rejecting the packet due to failing TEST2. In B's next packet to A, it will set pkt->org = peer->xmt and peer->aorg = pkt->xmt, ensuring that the packet will pass TEST2 at A, causing it to be accepted by A, and overwriting any previous value of peer->aorg at B. A will update its peer variables for B as well, ensuring that A's next packet will be accepted by B. From this point on, the symmetric association between A and B has successfully resynchronized. Thus, we see that recovery from packet loss or peer restart is not hampered by allowing peer->aorg to maintain its previous value when a packet with a zero origin timestamp is received. Further to the point, ntpd versions prior to ntp-4.2.8p6 did not clear peer->aorg upon receipt of a packet bearing a zero origin timestamp. ### Mitigation The only ntpd-based mitigations for this vulnerability are to try to make it harder for an attacker to guess the peers of ntpd instances and to monitor ntpd logs for messages such as the following: ``` ntpd[16767]: receive: Drop 0 origin timestamp from [email protected] xmt 0xdbe84918.63324800 ntpd[16767]: receive: Unexpected origin timestamp 0xdbe849a1.279a6fea does not match aorg 0000000000.00000000 from [email protected] xmt 0xdbe849a4.52a12e3a ``` All ntpd instances should be configured to block control queries from untrusted servers. This is best practice. All ntpd clients should block all incoming traffic that does not originate from a known peer address. This can be accomplished with a stateful firewall. Because peer->aorg is cleared before authentication is enforced, enabling NTP authentication does not prevent exploitation of this vulnerability. ### Timeline * 2017-01-04 - Vendor Disclosure * 2017-03-29 - Public Release ### CREDIT * Discovered by Matthew Van Gundy of Cisco ASIG.
idSSV:96543
last seen2017-11-19
modified2017-09-20
published2017-09-20
reporterRoot
titleNetwork Time Protocol Origin Timestamp Check Denial of Service Vulnerability(CVE-2016-9042)

Talos

idTALOS-2016-0260
last seen2019-05-29
published2017-03-29
reporterTalos Intelligence
sourcehttp://www.talosintelligence.com/vulnerability_reports/TALOS-2016-0260
titleNetwork Time Protocol Origin Timestamp Check Denial of Service Vulnerability

References