CVE-2016-7426

NTP before 4.2.8p9 rate limits responses received from the configured sources when rate limiting for all associations is enabled, which allows remote attackers to cause a denial of service (prevent responses from the sources) by sending responses with a spoofed source address.

Weakness

The product does not properly control the allocation and maintenance of a limited resource.

Affected Software

Name	Vendor	Start Version	End Version
Ntp	Ntp	4.2.6 (including)	4.2.8 (excluding)
Ntp	Ntp	4.3.0 (including)	4.3.94 (excluding)
Ntp	Ntp	4.2.5-p203 (including)	4.2.5-p203 (including)
Ntp	Ntp	4.2.5-p204 (including)	4.2.5-p204 (including)
Ntp	Ntp	4.2.5-p205 (including)	4.2.5-p205 (including)
Ntp	Ntp	4.2.5-p206 (including)	4.2.5-p206 (including)
Ntp	Ntp	4.2.5-p207 (including)	4.2.5-p207 (including)
Ntp	Ntp	4.2.5-p208 (including)	4.2.5-p208 (including)
Ntp	Ntp	4.2.5-p209 (including)	4.2.5-p209 (including)
Ntp	Ntp	4.2.5-p210 (including)	4.2.5-p210 (including)
Ntp	Ntp	4.2.5-p211 (including)	4.2.5-p211 (including)
Ntp	Ntp	4.2.5-p212 (including)	4.2.5-p212 (including)
Ntp	Ntp	4.2.5-p213 (including)	4.2.5-p213 (including)
Ntp	Ntp	4.2.5-p214 (including)	4.2.5-p214 (including)
Ntp	Ntp	4.2.5-p215 (including)	4.2.5-p215 (including)
Ntp	Ntp	4.2.5-p216 (including)	4.2.5-p216 (including)
Ntp	Ntp	4.2.5-p217 (including)	4.2.5-p217 (including)
Ntp	Ntp	4.2.5-p218 (including)	4.2.5-p218 (including)
Ntp	Ntp	4.2.5-p219 (including)	4.2.5-p219 (including)
Ntp	Ntp	4.2.5-p220 (including)	4.2.5-p220 (including)
Ntp	Ntp	4.2.5-p221 (including)	4.2.5-p221 (including)
Ntp	Ntp	4.2.5-p222 (including)	4.2.5-p222 (including)
Ntp	Ntp	4.2.5-p223 (including)	4.2.5-p223 (including)
Ntp	Ntp	4.2.5-p224 (including)	4.2.5-p224 (including)
Ntp	Ntp	4.2.5-p225 (including)	4.2.5-p225 (including)
Ntp	Ntp	4.2.5-p226 (including)	4.2.5-p226 (including)
Ntp	Ntp	4.2.5-p227 (including)	4.2.5-p227 (including)
Ntp	Ntp	4.2.5-p228 (including)	4.2.5-p228 (including)
Ntp	Ntp	4.2.5-p229 (including)	4.2.5-p229 (including)
Ntp	Ntp	4.2.5-p230 (including)	4.2.5-p230 (including)
Ntp	Ntp	4.2.5-p231_rc1 (including)	4.2.5-p231_rc1 (including)
Ntp	Ntp	4.2.5-p232_rc1 (including)	4.2.5-p232_rc1 (including)
Ntp	Ntp	4.2.5-p233_rc1 (including)	4.2.5-p233_rc1 (including)
Ntp	Ntp	4.2.5-p234_rc1 (including)	4.2.5-p234_rc1 (including)
Ntp	Ntp	4.2.5-p235_rc1 (including)	4.2.5-p235_rc1 (including)
Ntp	Ntp	4.2.5-p236_rc1 (including)	4.2.5-p236_rc1 (including)
Ntp	Ntp	4.2.5-p237_rc1 (including)	4.2.5-p237_rc1 (including)
Ntp	Ntp	4.2.5-p238_rc1 (including)	4.2.5-p238_rc1 (including)
Ntp	Ntp	4.2.5-p239_rc1 (including)	4.2.5-p239_rc1 (including)
Ntp	Ntp	4.2.5-p240_rc1 (including)	4.2.5-p240_rc1 (including)
Ntp	Ntp	4.2.5-p241_rc1 (including)	4.2.5-p241_rc1 (including)
Ntp	Ntp	4.2.5-p242_rc1 (including)	4.2.5-p242_rc1 (including)
Ntp	Ntp	4.2.5-p243_rc1 (including)	4.2.5-p243_rc1 (including)
Ntp	Ntp	4.2.5-p244_rc1 (including)	4.2.5-p244_rc1 (including)
Ntp	Ntp	4.2.5-p245_rc1 (including)	4.2.5-p245_rc1 (including)
Ntp	Ntp	4.2.5-p246_rc1 (including)	4.2.5-p246_rc1 (including)
Ntp	Ntp	4.2.5-p247_rc1 (including)	4.2.5-p247_rc1 (including)
Ntp	Ntp	4.2.5-p248_rc1 (including)	4.2.5-p248_rc1 (including)
Ntp	Ntp	4.2.5-p249_rc1 (including)	4.2.5-p249_rc1 (including)
Ntp	Ntp	4.2.5-p250_rc1 (including)	4.2.5-p250_rc1 (including)
Ntp	Ntp	4.2.8 (including)	4.2.8 (including)
Ntp	Ntp	4.2.8-p1 (including)	4.2.8-p1 (including)
Ntp	Ntp	4.2.8-p1-beta1 (including)	4.2.8-p1-beta1 (including)
Ntp	Ntp	4.2.8-p1-beta2 (including)	4.2.8-p1-beta2 (including)
Ntp	Ntp	4.2.8-p1-beta3 (including)	4.2.8-p1-beta3 (including)
Ntp	Ntp	4.2.8-p1-beta4 (including)	4.2.8-p1-beta4 (including)
Ntp	Ntp	4.2.8-p1-beta5 (including)	4.2.8-p1-beta5 (including)
Ntp	Ntp	4.2.8-p1-rc1 (including)	4.2.8-p1-rc1 (including)
Ntp	Ntp	4.2.8-p1-rc2 (including)	4.2.8-p1-rc2 (including)
Ntp	Ntp	4.2.8-p2 (including)	4.2.8-p2 (including)
Ntp	Ntp	4.2.8-p2-rc1 (including)	4.2.8-p2-rc1 (including)
Ntp	Ntp	4.2.8-p2-rc2 (including)	4.2.8-p2-rc2 (including)
Ntp	Ntp	4.2.8-p2-rc3 (including)	4.2.8-p2-rc3 (including)
Ntp	Ntp	4.2.8-p3 (including)	4.2.8-p3 (including)
Ntp	Ntp	4.2.8-p3-rc1 (including)	4.2.8-p3-rc1 (including)
Ntp	Ntp	4.2.8-p3-rc2 (including)	4.2.8-p3-rc2 (including)
Ntp	Ntp	4.2.8-p3-rc3 (including)	4.2.8-p3-rc3 (including)
Ntp	Ntp	4.2.8-p4 (including)	4.2.8-p4 (including)
Ntp	Ntp	4.2.8-p5 (including)	4.2.8-p5 (including)
Ntp	Ntp	4.2.8-p6 (including)	4.2.8-p6 (including)
Ntp	Ntp	4.2.8-p7 (including)	4.2.8-p7 (including)
Ntp	Ntp	4.2.8-p8 (including)	4.2.8-p8 (including)
Red Hat Enterprise Linux 6	RedHat	ntp-0:4.2.6p5-10.el6_8.2	*
Red Hat Enterprise Linux 7	RedHat	ntp-0:4.2.6p5-25.el7_3.1	*
Ntp	Ubuntu	esm-infra-legacy/trusty	*
Ntp	Ubuntu	esm-infra/xenial	*
Ntp	Ubuntu	precise	*
Ntp	Ubuntu	trusty	*
Ntp	Ubuntu	trusty/esm	*
Ntp	Ubuntu	upstream	*
Ntp	Ubuntu	vivid/stable-phone-overlay	*
Ntp	Ubuntu	xenial	*
Ntp	Ubuntu	yakkety	*

Potential Mitigations

Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

NVD	https://nvd.nist.gov/vuln/detail/CVE-2016-7426
CWE	https://cwe.mitre.org/data/definitions/400.html

Uncontrolled Resource Consumption

Weakness

Affected Software

Potential Mitigations

References

CVE-2016-7426

Uncontrolled Resource Consumption

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References