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CVE-2016-1551


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.


Security Impact Summary

This vulnerability carries a LOW severity rating with a CVSS v3.1 score of 3.7, indicating it can be exploited remotely over the network but requires specific conditions to be met without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts limited integrity, for affected systems. Impacting 2 products from ntp, from ntpsec organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2017, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.


Published

2017-01-27T17:59:00.227

Last Modified

2025-04-20T01:37:25.860

Status

Deferred

Source

[email protected]

Severity

CVSSv3.0: 3.7 (LOW)

CVSSv2 Vector

AV:N/AC:H/Au:N/C:N/I:P/A:N

  • Access Vector: NETWORK
  • Access Complexity: HIGH
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: PARTIAL
  • Availability Impact: NONE
Exploitability Score

4.9

Impact Score

2.9

Weaknesses
  • Type: Primary
    CWE-254

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application ntp ntp 4.2.8 Yes
Application ntpsec ntpsec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For ntp's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.