Vulnerabilities > CVE-2016-7431 - Improper Input Validation vulnerability in NTP 4.2.8
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
NONE Integrity impact
LOW Availability impact
NONE Summary
NTP before 4.2.8p9 allows remote attackers to bypass the origin timestamp protection mechanism via an origin timestamp of zero. NOTE: this vulnerability exists because of a CVE-2015-8138 regression.
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 family Slackware Local Security Checks NASL id SLACKWARE_SSA_2016-326-01.NASL description 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. last seen 2020-06-01 modified 2020-06-02 plugin id 95028 published 2016-11-22 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/95028 title Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : ntp (SSA:2016-326-01) code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from Slackware Security Advisory 2016-326-01. The text # itself is copyright (C) Slackware Linux, Inc. # include("compat.inc"); if (description) { script_id(95028); script_version("2.3"); script_cvs_date("Date: 2019/04/11 17:23:07"); script_cve_id("CVE-2016-7426", "CVE-2016-7427", "CVE-2016-7428", "CVE-2016-7429", "CVE-2016-7431", "CVE-2016-7433", "CVE-2016-7434", "CVE-2016-9310", "CVE-2016-9311", "CVE-2016-9312"); script_xref(name:"SSA", value:"2016-326-01"); script_name(english:"Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : ntp (SSA:2016-326-01)"); 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 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=2016&m=slackware-security.641761 script_set_attribute( attribute:"see_also", value:"http://www.nessus.org/u?271e3ad7" ); 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:N/UI:N/S:U/C:N/I:N/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: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:"2016/11/21"); script_set_attribute(attribute:"plugin_publication_date", value:"2016/11/22"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2016-2019 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:"13.0", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i486", pkgnum:"1_slack13.0")) flag++; if (slackware_check(osver:"13.0", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1_slack13.0")) flag++; if (slackware_check(osver:"13.1", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i486", pkgnum:"1_slack13.1")) flag++; if (slackware_check(osver:"13.1", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1_slack13.1")) flag++; if (slackware_check(osver:"13.37", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i486", pkgnum:"1_slack13.37")) flag++; if (slackware_check(osver:"13.37", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1_slack13.37")) flag++; if (slackware_check(osver:"14.0", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i486", pkgnum:"1_slack14.0")) flag++; if (slackware_check(osver:"14.0", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1_slack14.0")) flag++; if (slackware_check(osver:"14.1", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i486", pkgnum:"1_slack14.1")) flag++; if (slackware_check(osver:"14.1", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1_slack14.1")) flag++; if (slackware_check(osver:"14.2", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i586", pkgnum:"1_slack14.2")) flag++; if (slackware_check(osver:"14.2", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1_slack14.2")) flag++; if (slackware_check(osver:"current", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"i586", pkgnum:"1")) flag++; if (slackware_check(osver:"current", arch:"x86_64", pkgname:"ntp", pkgver:"4.2.8p9", pkgarch:"x86_64", pkgnum:"1")) flag++; if (flag) { if (report_verbosity > 0) security_hole(port:0, extra:slackware_report_get()); else security_hole(0); exit(0); } else audit(AUDIT_HOST_NOT, "affected");
NASL family SuSE Local Security Checks NASL id SUSE_SU-2017-0255-1.NASL description This update for ntp fixes the following issues: ntp was updated to 4.2.8p9. Security issues fixed : - CVE-2016-9311, CVE-2016-9310, bsc#1011377: Mode 6 unauthenticated trap information disclosure and DDoS vector. - CVE-2016-7427, bsc#1011390: Broadcast Mode Replay Prevention DoS. - CVE-2016-7428, bsc#1011417: Broadcast Mode Poll Interval Enforcement DoS. - CVE-2016-7431, bsc#1011395: Regression: 010-origin: Zero Origin Timestamp Bypass. - CVE-2016-7434, bsc#1011398: NULL pointer dereference in _IO_str_init_static_internal(). - CVE-2016-7429, bsc#1011404: Interface selection attack. - CVE-2016-7426, bsc#1011406: Client rate limiting and server responses. - CVE-2016-7433, bsc#1011411: Reboot sync calculation problem. - CVE-2015-8140: ntpq vulnerable to replay attacks. - CVE-2015-8139: Origin Leak: ntpq and ntpdc, disclose origin. - CVE-2015-5219: An endless loop due to incorrect precision to double conversion (bsc#943216). Non-security issues fixed : - Fix a spurious error message. - Other bugfixes, see /usr/share/doc/packages/ntp/ChangeLog. - Fix a regression in last seen 2020-06-01 modified 2020-06-02 plugin id 96715 published 2017-01-24 reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/96715 title SUSE SLES11 Security Update : ntp (SUSE-SU-2017:0255-1) NASL family SuSE Local Security Checks NASL id SUSE_SU-2016-3196-1.NASL description This update for ntp fixes the following issues: ntp was updated to 4.2.8p9. Security issues fixed : - CVE-2016-9311, CVE-2016-9310, bsc#1011377: Mode 6 unauthenticated trap information disclosure and DDoS vector. - CVE-2016-7427, bsc#1011390: Broadcast Mode Replay Prevention DoS. - CVE-2016-7428, bsc#1011417: Broadcast Mode Poll Interval Enforcement DoS. - CVE-2016-7431, bsc#1011395: Regression: 010-origin: Zero Origin Timestamp Bypass. - CVE-2016-7434, bsc#1011398: NULL pointer dereference in _IO_str_init_static_internal(). - CVE-2016-7429, bsc#1011404: Interface selection attack. - CVE-2016-7426, bsc#1011406: Client rate limiting and server responses. - CVE-2016-7433, bsc#1011411: Reboot sync calculation problem. - CVE-2015-5219: An endless loop due to incorrect precision to double conversion (bsc#943216). Non-security issues fixed : - Fix a spurious error message. - Other bugfixes, see /usr/share/doc/packages/ntp/ChangeLog. - Fix a regression in last seen 2020-06-01 modified 2020-06-02 plugin id 95988 published 2016-12-21 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/95988 title SUSE SLES12 Security Update : ntp (SUSE-SU-2016:3196-1) NASL family Ubuntu Local Security Checks NASL id UBUNTU_USN-3349-1.NASL description 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. last seen 2020-06-01 modified 2020-06-02 plugin id 101263 published 2017-07-06 reporter Ubuntu Security Notice (C) 2017-2019 Canonical, Inc. / NASL script (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/101263 title Ubuntu 14.04 LTS / 16.04 LTS / 16.10 / 17.04 : ntp vulnerabilities (USN-3349-1) NASL family SuSE Local Security Checks NASL id SUSE_SU-2016-3195-1.NASL description This update for ntp fixes the following issues: ntp was updated to 4.2.8p9. Security issues fixed : - CVE-2016-9311, CVE-2016-9310, bsc#1011377: Mode 6 unauthenticated trap information disclosure and DDoS vector. - CVE-2016-7427, bsc#1011390: Broadcast Mode Replay Prevention DoS. - CVE-2016-7428, bsc#1011417: Broadcast Mode Poll Interval Enforcement DoS. - CVE-2016-7431, bsc#1011395: Regression: 010-origin: Zero Origin Timestamp Bypass. - CVE-2016-7434, bsc#1011398: NULL pointer dereference in _IO_str_init_static_internal(). - CVE-2016-7429, bsc#1011404: Interface selection attack. - CVE-2016-7426, bsc#1011406: Client rate limiting and server responses. - CVE-2016-7433, bsc#1011411: Reboot sync calculation problem. - CVE-2015-5219: An endless loop due to incorrect precision to double conversion (bsc#943216). Non-security issues fixed : - Fix a spurious error message. - Other bugfixes, see /usr/share/doc/packages/ntp/ChangeLog. - Fix a regression in last seen 2020-06-01 modified 2020-06-02 plugin id 95987 published 2016-12-21 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/95987 title SUSE SLED12 / SLES12 Security Update : ntp (SUSE-SU-2016:3195-1) NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_FCEDCDBBC86E11E6B1CF14DAE9D210B8.NASL description Multiple vulnerabilities have been discovered in the NTP suite : CVE-2016-9311: Trap crash, Reported by Matthew Van Gundy of Cisco ASIG. CVE-2016-9310: Mode 6 unauthenticated trap information disclosure and DDoS vector. Reported by Matthew Van Gundy of Cisco ASIG. CVE-2016-7427: Broadcast Mode Replay Prevention DoS. Reported by Matthew Van Gundy of Cisco ASIG. CVE-2016-7428: Broadcast Mode Poll Interval Enforcement DoS. Reported by Matthew Van Gundy of Cisco ASIG. CVE-2016-7431: Regression: 010-origin: Zero Origin Timestamp Bypass. Reported by Sharon Goldberg and Aanchal Malhotra of Boston University. CVE-2016-7434: NULL pointer dereference in _IO_str_init_static_internal(). Reported by Magnus Stubman. CVE-2016-7426: Client rate limiting and server responses. Reported by Miroslav Lichvar of Red Hat. CVE-2016-7433: Reboot sync calculation problem. Reported independently by Brian Utterback of Oracle, and by Sharon Goldberg and Aanchal Malhotra of Boston University. Impact : A remote attacker who can send a specially crafted packet to cause a NULL pointer dereference that will crash ntpd, resulting in a Denial of Service. [CVE-2016-9311] An exploitable configuration modification vulnerability exists in the control mode (mode 6) functionality of ntpd. If, against long-standing BCP recommendations, last seen 2020-06-01 modified 2020-06-02 plugin id 96123 published 2016-12-27 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/96123 title FreeBSD : FreeBSD -- Multiple vulnerabilities of ntp (fcedcdbb-c86e-11e6-b1cf-14dae9d210b8) NASL family CGI abuses NASL id ORACLE_ILOM_3_2_6.NASL description According to its self-reported version number, the version of Oracle Integrated Lights Out Manager (ILOM) is affected by multiple vulnerabilities as described in the advisory. last seen 2020-06-01 modified 2020-06-02 plugin id 104047 published 2017-10-20 reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/104047 title Oracle Integrated Lights Out Manager (ILOM) < 3.2.6 Multiple Vulnerabilities (uncredentialed check) NASL family Misc. NASL id NTP_4_2_8P9.NASL description The version of the remote NTP server is 4.x prior to 4.2.8p9. It is, therefore, affected by the following vulnerabilities : - A denial of service vulnerability exists when rate limiting is configured for all associations, the limits also being applied to responses received from the configured sources. An unauthenticated, remote attacker can exploit this, by periodically sending spoofed packets, to keep rate limiting active, resulting in valid responses not being accepted by ntpd from its sources. (CVE-2016-7426) - A denial of service vulnerability exists in the broadcast mode replay prevention functionality. An unauthenticated, adjacent attacker can exploit this, via specially crafted broadcast mode NTP packets periodically injected into the broadcast domain, to cause ntpd to reject broadcast mode packets from legitimate NTP broadcast servers. (CVE-2016-7427) - A denial of service vulnerability exists in the broadcast mode poll interval functionality. An unauthenticated, adjacent attacker can exploit this, via specially crafted broadcast mode NTP packets, to cause ntpd to reject packets from a legitimate NTP broadcast server. (CVE-2016-7428) - A denial of service vulnerability exists when receiving server responses on sockets that correspond to different interfaces than what were used in the request. An unauthenticated, remote attacker can exploit this, by sending repeated requests using specially crafted packets with spoofed source addresses, to cause ntpd to select the incorrect interface for the source, which prevents it from sending new requests until the interface list is refreshed. This eventually results in preventing ntpd from synchronizing with the source. (CVE-2016-7429) - A flaw exists that allows packets with an origin timestamp of zero to bypass security checks. An unauthenticated, remote attacker can exploit this to spoof arbitrary content. (CVE-2016-7431) - A flaw exists due to the root delay being included twice, which may result in the jitter value being higher than expected. An unauthenticated, remote attacker can exploit this to cause a denial of service condition. (CVE-2016-7433) - A denial of service vulnerability exists when handling specially crafted mrulist query packets that allows an unauthenticated, remote attacker to crash ntpd. (CVE-2016-7434) - A flaw exists in the control mode (mode 6) functionality when handling specially crafted control mode packets. An unauthenticated, adjacent attacker can exploit this to set or disable ntpd traps, resulting in the disclosure of potentially sensitive information, disabling of legitimate monitoring, or DDoS amplification. (CVE-2016-9310) - A NULL pointer dereference flaw exists in the report_event() function within file ntpd/ntp_control.c when the trap service handles certain peer events. An unauthenticated, remote attacker can exploit this, via a specially crafted packet, to cause a denial of service condition. (CVE-2016-9311) - A denial of service vulnerability exists when handling oversize UDP packets that allows an unauthenticated, remote attacker to crash ntpd. Note that this vulnerability only affects Windows versions. (CVE-2016-9312) last seen 2020-04-30 modified 2016-12-06 plugin id 95575 published 2016-12-06 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/95575 title Network Time Protocol Daemon (ntpd) 4.x < 4.2.8p9 Multiple Vulnerabilities NASL family PhotonOS Local Security Checks NASL id PHOTONOS_PHSA-2017-0003.NASL description An update of [guile,ntp] packages for PhotonOS has been released. last seen 2019-02-08 modified 2019-02-07 plugin id 111852 published 2018-08-17 reporter Tenable source https://www.tenable.com/plugins/index.php?view=single&id=111852 title Photon OS 1.0: Guile / Ntp / Ntpstat PHSA-2017-0003 (deprecated) NASL family SuSE Local Security Checks NASL id SUSE_SU-2016-3193-1.NASL description This update for ntp fixes the following issues : - Simplify ntpd last seen 2020-06-01 modified 2020-06-02 plugin id 95986 published 2016-12-21 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/95986 title SUSE SLES11 Security Update : ntp (SUSE-SU-2016:3193-1) NASL family FreeBSD Local Security Checks NASL id FREEBSD_PKG_8DB8D62AB08B11E68EBAD050996490D0.NASL description Network Time Foundation reports : NTF last seen 2020-06-01 modified 2020-06-02 plugin id 95265 published 2016-11-23 reporter This script is Copyright (C) 2016-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/95265 title FreeBSD : ntp -- multiple vulnerabilities (8db8d62a-b08b-11e6-8eba-d050996490d0) NASL family PhotonOS Local Security Checks NASL id PHOTONOS_PHSA-2017-0003_NTP.NASL description An update of the ntp package has been released. last seen 2020-06-01 modified 2020-06-02 plugin id 121668 published 2019-02-07 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/121668 title Photon OS 1.0: Ntp PHSA-2017-0003 NASL family SuSE Local Security Checks NASL id OPENSUSE-2016-1525.NASL description This update for ntp fixes the following issues : ntp was updated to 4.2.8p9. Security issues fixed : - CVE-2016-9311, CVE-2016-9310, bsc#1011377: Mode 6 unauthenticated trap information disclosure and DDoS vector. - CVE-2016-7427, bsc#1011390: Broadcast Mode Replay Prevention DoS. - CVE-2016-7428, bsc#1011417: Broadcast Mode Poll Interval Enforcement DoS. - CVE-2016-7431, bsc#1011395: Regression: 010-origin: Zero Origin Timestamp Bypass. - CVE-2016-7434, bsc#1011398: NULL pointer dereference in _IO_str_init_static_internal(). - CVE-2016-7429, bsc#1011404: Interface selection attack. - CVE-2016-7426, bsc#1011406: Client rate limiting and server responses. - CVE-2016-7433, bsc#1011411: Reboot sync calculation problem. - CVE-2015-5219: An endless loop due to incorrect precision to double conversion (bsc#943216). Non-security issues fixed : - Fix a spurious error message. - Other bugfixes, see /usr/share/doc/packages/ntp/ChangeLog. - Fix a regression in last seen 2020-06-05 modified 2016-12-29 plugin id 96173 published 2016-12-29 reporter This script is Copyright (C) 2016-2020 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/96173 title openSUSE Security Update : ntp (openSUSE-2016-1525) NASL family Firewalls NASL id PFSENSE_SA-17_03.NASL description According to its self-reported version number, the remote pfSense install is affected by multiple vulnerabilities as stated in the referenced vendor advisories. last seen 2020-06-01 modified 2020-06-02 plugin id 106503 published 2018-01-31 reporter This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/106503 title pfSense < 2.3.3 Multiple Vulnerabilities (SA-17_01 - SA-17_03) NASL family PhotonOS Local Security Checks NASL id PHOTONOS_PHSA-2017-0003_NTPSTAT.NASL description An update of the ntpstat package has been released. last seen 2020-06-01 modified 2020-06-02 plugin id 121669 published 2019-02-07 reporter This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/121669 title Photon OS 1.0: Ntpstat PHSA-2017-0003
Seebug
bulletinFamily | exploit |
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. |
id | SSV:96543 |
last seen | 2017-11-19 |
modified | 2017-09-20 |
published | 2017-09-20 |
reporter | Root |
title | Network Time Protocol Origin Timestamp Check Denial of Service Vulnerability(CVE-2016-9042) |
Talos
id | TALOS-2016-0260 |
last seen | 2019-05-29 |
published | 2017-03-29 |
reporter | Talos Intelligence |
source | http://www.talosintelligence.com/vulnerability_reports/TALOS-2016-0260 |
title | Network Time Protocol Origin Timestamp Check Denial of Service Vulnerability |
References
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