CVE-2015-5300 – ntp: MITM attacker can force ntpd to make a step larger than the panic threshold

https://notcve.org/view.php?id=CVE-2015-5300

The panic_gate check in NTP before 4.2.8p5 is only re-enabled after the first change to the system clock that was greater than 128 milliseconds by default, which allows remote attackers to set NTP to an arbitrary time when started with the -g option, or to alter the time by up to 900 seconds otherwise by responding to an unspecified number of requests from trusted sources, and leveraging a resulting denial of service (abort and restart). La comprobación panic_gate en NTP anterior a versión 4.2.8p5 es solo habilitada nuevamente después del primer cambio al reloj del sistema que fue mayor que 128 milisegundos por defecto, permitiendo a los atacantes remotos fijar el NTP a un tiempo arbitrario cuando arranca con la opción -g, o alterar el tiempo hasta 900 segundos, de lo contrario por respuesta a un número no especificado de peticiones de fuentes de confianza y aprovechando una denegación de servicio resultante (anular y reiniciar). It was found that ntpd did not correctly implement the threshold limitation for the '-g' option, which is used to set the time without any restrictions. A man-in-the-middle attacker able to intercept NTP traffic between a connecting client and an NTP server could use this flaw to force that client to make multiple steps larger than the panic threshold, effectively changing the time to an arbitrary value at any time. • http://aix.software.ibm.com/aix/efixes/security/ntp_advisory5.asc http://lists.fedoraproject.org/pipermail/package-announce/2015-November/170684.html http://lists.fedoraproject.org/pipermail/package-announce/2015-November/170926.html http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177507.html http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00059.html http://lists.opensuse.org/opensuse-security-announce/2016-04/msg00060.html http://lists.opensuse.org/opensuse-security-announc • CWE-20: Improper Input Validation CWE-361: 7PK - Time and State •