ntprequest.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODEPRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODEPRIVATE error responses between two NTP daemons.
NTP 4.x before 4.2.8p6 and 4.3.x before 4.3.90 do not verify peer associations of symmetric keys when authenticating packets, which might allow remote attackers to conduct impersonation attacks via an arbitrary trusted key, aka a "skeleton key."
Buffer overflow in the password management functionality in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote authenticated users to cause a denial of service (daemon crash) or possibly execute arbitrary code via a crafted key file.
It was found that NTP's decodenetnum() would abort with an assertion failure when processing a mode 6 or mode 7 packet containing an unusually long data value where a network address was expected. This could allow an authenticated attacker to crash ntpd.
External References:
https://github.com/ntp-project/ntp/blob/stable/NEWS#L295 http://support.ntp.org/bin/view/Main/SecurityNotice#October2015NTPSecurityVulner
ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote authenticated users to cause a denial of service (infinite loop or crash) by pointing the key file at the log file.
ntpq in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (crash) via crafted mode 6 response packets.
The following flaw was found in ntpd:
An exploitable use-after-free vulnerability exists in the password management functionality of the Network Time Protocol. A specially crafted key file could cause a buffer overflow resulting in memory corruption. An attacker could provide a malicious password file to trigger this vulnerability.
External References:
http://talosintel.com/reports/TALOS-2015-0054/ http://support.ntp.org/bin/view/Main/SecurityNotice#October2015NTPSecurityVulner
The datalen parameter in the refclock driver in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to execute arbitrary code or cause a denial of service (crash) via a negative input value.
The "pidfile" or "driftfile" directives in NTP ntpd 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77, when ntpd is configured to allow remote configuration, allows remote attackers with an IP address that is allowed to send configuration requests, and with knowledge of the remote configuration password to write to arbitrary files via the :config command.
Directory traversal vulnerability in the saveconfig function in ntpd in ntpcontrol.c in NTP before 4.2.8p4, when used on systems that do not use '\' or '/' characters for directory separation such as OpenVMS, allows remote authenticated users to overwrite arbitrary files.
A memory leak flaw was found in ntpd's CRYPTOASSOC. If ntpd is configured to use autokey authentication, an attacker could send packets to ntpd that would, after several days of ongoing attack, cause it to run out of memory.
Mitigation:
Disable NTP autokey authentication by removing, or commenting out, all configuration directives beginning with the 'crypto' keyword in your ntp.conf file.
External References:
https://github.com/ntp-project/ntp/blob/stable/NEWS#L91 http://support.ntp.org/bin/view/Main/SecurityNotice#October2015NTPSecurityVulner
It was found that the fix for CVE-2014-9750 was incomplete: three issues were found in the value length checks in ntpcrypto.c, where a packet with particular autokey operations that contained malicious data was not always being completely validated. Receipt of these packets can cause ntpd to crash.
Upstream patch:
https://github.com/ntp-project/ntp/commit/c4cd4aaf418f57f7225708a93bf48afb2bc9c1da
Mitigation:
Disable NTP autokey authentication by removing, or commenting out, all configuration directives beginning with the 'crypto' keyword in your ntp.conf file.
External References:
https://github.com/ntp-project/ntp/blob/stable/NEWS#L11 http://support.ntp.org/bin/view/Main/SecurityNotice#October2015NTPSecurityVulner
The ntpd client in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service via a number of crafted "KOD" messages.
The cryptoxmit function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (crash). NOTE: This vulnerability exists due to an incomplete fix for CVE-2014-9750.
A flaw was found in the way NTP handled rate limiting. An attacker able to send a large number of crafted requests to an NTP server could trigger the rate limiting on that server, and prevent clients from getting a usable reply from the server.
The default NTP configuration in Red Hat Enterprise Linux does not enable rate limiting.
External References:
https://www.cs.bu.edu/~goldbe/NTPattack.html
The cryptoxmit function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (crash). NOTE: This vulnerability exists due to an incomplete fix for CVE-2014-9750.
ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (interleaved-mode transition and time change) via a spoofed broadcast packet. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-1548.
ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause a denial of service (peer-variable clearing and association outage) by sending (1) a spoofed crypto-NAK packet or (2) a packet with an incorrect MAC value at a certain time.
ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (ephemeral-association demobilization) by sending a spoofed crypto-NAK packet with incorrect authentication data at a certain time.
The processpacket function in ntpproto.c in ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (peer-variable modification) by sending spoofed packets from many source IP addresses in a certain scenario, as demonstrated by triggering an incorrect leap indication.