Last updated 25 August 2025
Last updated 25 August 2025
Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.
Last updated 25 August 2025
Last updated 25 August 2025
Last updated 25 August 2025
ntpd can be vulnerable to Sybil attacks. If a system is set up to use a trustedkey and if one is not using the feature introduced in ntp-4.2.8p6 allowing an optional 4th field in the ntp.keys file to specify which IPs can serve time, a malicious authenticated peer -- i.e. one where the attacker knows the private symmetric key -- can create arbitrarily-many ephemeral associations in order to win the clock selection of ntpd and modify a victim's clock.
Ps.: This is possibly a incomplete fix for CVE-2016-1549.
References:
http://support.ntp.org/bin/view/Main/NtpBug3415
Last updated 24 July 2024
Last updated 24 July 2024
ntp. Multiple issues were addressed by updating to version 4.2.8p10
ntp. Multiple issues were addressed by updating to version 4.2.8p10
ntp. Multiple issues were addressed by updating to version 4.2.8p10
NTP before 4.2.8p10 and 4.3.x before 4.3.94, when using PPSAPI, allows local users to gain privileges via a DLL in the PPSAPIDLLS environment variable.
A vulnerability found in the NTP server allows an authenticated remote attacker to crash the daemon by sending an invalid setting via the :config directive. The unpeer option expects a number or an address as an argument. In case the value is "0", a segmentation fault occurs.
Affects: All versions of ntp, up to but not including ntp-4.2.8p10, and ntp-4.3.0 up to, but not including ntp-4.3.94.
Mitigation:
Properly monitor your ntpd instances, and auto-restart ntpd (without -g) if it stops running.
Buffer overflow in the legacy Datum Programmable Time Server (DPTS) refclock driver in NTP before 4.2.8p10 and 4.3.x before 4.3.94 allows local users to have unspecified impact via a crafted /dev/datum device.
A vulnerability found in the NTP server makes it possible for an authenticated remote user to crash ntpd via a malformed mode configuration directive.
Mitigation:
Properly monitor your ntpd instances, and auto-restart ntpd (without -g) if it stops running.
Last updated 24 July 2024
The getresponse function in ntpq in NTP versions before 4.2.8p9 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (infinite loop) via crafted packets with incorrect values.
NTP before 4.2.8p7 and 4.3.x before 4.3.92, when mode7 is enabled, allows remote attackers to cause a denial of service (ntpd abort) by using the same IP address multiple times in an unconfig directive.
NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to bypass the origin timestamp validation via a packet with an origin timestamp set to zero.
ntpd in NTP before 4.2.8p6 and 4.3.x before 4.3.90 allows remote attackers to cause a denial of service (NULL pointer dereference) via a ntpdc reslist command.
NTP before 4.2.8p6 and 4.3.0 before 4.3.90 allows a remote attackers to cause a denial of service (stack exhaustion) via an ntpdc relist command, which triggers recursive traversal of the restriction list.
The ntpq saveconfig command in NTP 4.1.2, 4.2.x before 4.2.8p6, 4.3, 4.3.25, 4.3.70, and 4.3.77 does not properly filter special characters, which allows attackers to cause unspecified impact via a crafted filename.
The ntpq protocol in NTP before 4.2.8p7 allows remote attackers to conduct replay attacks by sniffing the network.
ntpq in NTP before 4.2.8p7 allows remote attackers to obtain origin timestamps and then impersonate peers via unspecified vectors.
NTP before 4.2.8p7 and 4.3.x before 4.3.92 allows remote attackers to cause a denial of service (prevent subsequent authentication) by leveraging knowledge of the controlkey or requestkey and sending a crafted packet to ntpd, which changes the value of trustedkey, controlkey, or requestkey. NOTE: this vulnerability exists because of a CVE-2016-2516 regression.
The nextvar function in NTP before 4.2.8p6 and 4.3.x before 4.3.90 does not properly validate the length of its input, which allows an attacker to cause a denial of service (application crash).
NTP before 4.2.8p6 and 4.3.x before 4.3.90, when configured in broadcast mode, allows man-in-the-middle attackers to conduct replay attacks by sniffing the network.
ntpd in NTP 4.2.8p3 and NTPsec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 relies on the underlying operating system to protect it from requests that impersonate reference clocks. Because reference clocks are treated like other peers and stored in the same structure, any packet with a source ip address of a reference clock (127.127.1.1 for example) that reaches the receive() function will match that reference clock's peer record and will be treated as a trusted peer. Any system that lacks the typical martian packet filtering which would block these packets is in danger of having its time controlled by an attacker.
Last updated 25 August 2025