ntpd up to 4.2.8p8/4.3.93 UDP Packet input validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability classified as critical was found in ntpd up to 4.2.8p8/4.3.93 (Network Management Software). Affected by this vulnerability is an unknown functionality of the component UDP Packet Handler. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect availability.

The bug was discovered 06/24/2016. The weakness was published 11/21/2016 by Magnus Klaaborg Stubman as [CVE-2016-7434] ntpd remote pre-auth DoS as confirmed mailinglist post (Full-Disclosure). The advisory is shared at seclists.org. The public release has been coordinated with the project team. This vulnerability is known as CVE-2016-7434 since 09/09/2016. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are unknown but a public exploit is available.

It is declared as proof-of-concept. It is possible to download the exploit at exploit-db.com. The vulnerability was handled as a non-public zero-day exploit for at least 97 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 95986 (SUSE SLES11 Security Update : ntp (SUSE-SU-2016:3193-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks and running in the context local. The commercial vulnerability scanner Qualys is able to test this issue with plugin 371402 (Cisco UCS 6200 Series Fabric Interconnects Multiple Vulnerabilities in Network Time Protocol Daemon (CSCvc23476)).

Applying the patch 4.2.8p9/4.3.94 is able to eliminate this problem. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (95986) and Exploit-DB (40806). Similar entries are available at 95317, 95318, 95319 and 95320.





  • open-source

CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.5
VulDB Temp Score: 6.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍



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Class: Input validation
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

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EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 95986
Nessus Name: SUSE SLES11 Security Update : ntp (SUSE-SU-2016:3193-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 800407
OpenVAS Name: NTP.org ntp DoS Vulnerability
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍

Patch: 4.2.8p9/4.3.94


06/24/2016 🔍
06/26/2016 +2 days 🔍
06/26/2016 +0 days 🔍
09/09/2016 +75 days 🔍
09/29/2016 +20 days 🔍
11/21/2016 +53 days 🔍
11/21/2016 +0 days 🔍
11/22/2016 +1 days 🔍
12/21/2016 +29 days 🔍
01/13/2017 +23 days 🔍
10/04/2022 +2090 days 🔍


Advisory: [CVE-2016-7434] ntpd remote pre-auth DoS
Researcher: Magnus Klaaborg Stubman
Status: Confirmed
Confirmation: 🔍
Coordinated: 🔍

CVE: CVE-2016-7434 (🔍)

SecurityTracker: 1037354
SecurityFocus: 94448 - NTP CVE-2016-7434 Local Denial of Service Vulnerability

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍


Created: 11/22/2016 10:11 PM
Updated: 10/04/2022 10:41 AM
Changes: 11/22/2016 10:11 PM (79), 06/07/2019 03:48 PM (15), 10/04/2022 10:41 AM (4)
Complete: 🔍


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