An integer overflow can occur in NTP-dev.4.3.70 leading to an out-of-bounds memory copy operation when processing a specially crafted private mode packet. The crafted packet needs to have the correct message authentication code and a valid timestamp. When processed by the NTP daemon, it leads to an immediate crash.
NTP is vulnerable to a denial of service, caused by an issue when relying on unauthenticated IPv4 time sources in ntpd. By predicting transmit timestamps for use in spoofed packets, a remote attacker could exploit this vulnerability to cause the daemon to crash or system time change.
A vulnerability was found in NTP. A security issue which enables an off-path attacker to prevent ntpd from synchronizing with NTP servers not using authentication. A server mode packet with spoofed source address sent to the client ntpd causes the next transmission to be rescheduled, even if the packet doesn't have a valid origin timestamp. If the packet is sent to the client frequently enough, it will stop polling the server and not be able to synchronize with it.
An off-path attacker can cause a preemptible client association to be demobilized in NTP 4.2.8p4 and earlier and NTPSec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 by sending a crypto NAK packet to a victim client with a spoofed source address of an existing associated peer. This is true even if authentication is enabled.
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.
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.
It was found that ntpd did not correctly implement the -g option:
-g Normally, ntpd exits with a message to the system log if the offset exceeds the panic threshold, which is 1000 s by default. This option allows the time to be set to any value without restriction; however, this can happen only once. If the thresh‐ old is exceeded after that, ntpd will exit with a message to the system log. This option can be used with the -q and -x options. See the tinker command for other options.
ntpd could actually step the clock multiple times by more than the panic threshold if its clock discipline doesn't have enough time to reach the sync state and stay there for at least one update. If a man-in-the-middle attacker can control the NTP traffic since ntpd was started (or maybe up to 15-30 minutes after that), they can prevent the client from reaching the sync state and force it to step its clock by any amount any number of times, which can be used by attackers to expire certificates, etc.
This is contrary to what the documentation says. Normally, the assumption is that an MITM attacker can step the clock more than the panic threshold only once when ntpd starts and to make a larger adjustment the attacker has to divide it into multiple smaller steps, each taking 15 minutes, which is slow.
A flaw was found in the way ntpd processed certain remote configuration packets. An attacker could use a specially crafted package to cause ntpd to crash if:
ntpd enabled remote configuration The attacker had the knowledge of the configuration password The attacker had access to a computer entrusted to perform remote configuration
Note that remote configuration is disabled by default in NTP.
External References:
http://support.ntp.org/bin/view/Main/SecurityNotice#June2015NTPSecurityVulnerabi
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.