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

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 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.

Last updated 24 July 2024

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

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.

Last updated 25 August 2025

Last updated 25 August 2025

Last updated 25 August 2025

Last updated 25 August 2025

Last updated 25 August 2025

NTP 4.2.4 before 4.2.4p5 and 4.2.5 before 4.2.5p150 does not properly check the return value from the OpenSSL EVPVerifyFinal function, which allows remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature for DSA and ECDSA keys, a similar vulnerability to CVE-2008-5077.

It was found that when NTP is configured in broadcast mode, an off-path attacker could broadcast packets with bad authentication (wrong key, mismatched key, incorrect MAC, etc) to all clients. The clients, upon receiving the malformed packets, would break the association with the broadcast server. This could cause the time on affected clients to become out of sync over a longer period of time.

Upstream patch:

https://github.com/ntp-project/ntp/commit/fe46889f7baa75fc8e6c0fcde87706d396ce1461

The following flaw was found in ntpd:

Using a crafted packet to create a peer association with hmode > 7 causes the MATCHASSOC() lookup to make an out-of-bounds reference.

Upstream bugs:

http://support.ntp.org/bin/view/Main/NtpBug3009

External References:

http://support.ntp.org/bin/view/Main/SecurityNotice#April2016NTP428p7Security

Last updated 24 July 2024

Last updated 24 July 2024

Last updated 24 July 2024

Last updated 24 July 2024

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.