ntpd up to 4.2.8p7 Crypto-NAK Packet valid_NAK input validation

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.4$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, was found in ntpd up to 4.2.8p7. The impacted element is the function valid_NAK of the component Crypto-NAK Packet Handler. Executing a manipulation can lead to input validation. The identification of this vulnerability is CVE-2016-4957. The attack may be launched remotely. There is no exploit available. A patch should be applied to remediate this issue.

Detailsinfo

A vulnerability has been found in ntpd up to 4.2.8p7 (Network Management Software) and classified as critical. This vulnerability affects the function valid_NAK of the component Crypto-NAK 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. CVE summarizes:

ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-1547.

The weakness was shared 06/02/2016 as confirmed release notes (Website). The advisory is available at support.ntp.org. The vendor cooperated in the coordination of the public release. This vulnerability was named CVE-2016-4957 since 05/23/2016. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. Responsible for the vulnerability is the following code: 

if (peer->keyid > 0 || peer->flags & FLAG_SKEY) {
        return (VALIDNAK);

The vulnerability scanner Nessus provides a plugin with the ID 91662 (SUSE SLED12 / SLES12 Security Update : ntp (SUSE-SU-2016:1563-1)), 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 l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 371401 (Cisco UCS 6200 Series Fabric Interconnects Multiple Vulnerabilities in Network Time Protocol Daemon (CSCuz92668)).

Applying the patch 4.2.8p8 is able to eliminate this problem. A possible mitigation has been published before and not just after the disclosure of the vulnerability. The release notes contains the following remark:

NTP Consortium members at the Partner and Premier levels received pre-release patch access.

The vulnerability is also documented in the databases at Tenable (91662), SecurityFocus (BID 91010†) and SecurityTracker (ID 1036037†). Additional details are provided at kb.cert.org. The entries VDB-87750, VDB-87751, VDB-87752 and VDB-87753 are related to this item. If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.6
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.6
VulDB Temp Score: 8.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 8.6
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 91662
Nessus Name: SUSE SLED12 / SLES12 Security Update : ntp (SUSE-SU-2016:1563-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 862576
OpenVAS Name: SuSE Update for ntp SUSE-SU-2016:1568-1 (ntp)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: 4.2.8p8

Timelineinfo

05/23/2016 🔍
05/24/2016 +1 days 🔍
05/24/2016 +0 days 🔍
06/02/2016 +9 days 🔍
06/06/2016 +4 days 🔍
06/06/2016 +0 days 🔍
06/17/2016 +11 days 🔍
07/04/2016 +17 days 🔍
01/27/2025 +3129 days 🔍

Sourcesinfo

Advisory: support.ntp.org
Status: Confirmed
Confirmation: 🔍
Coordinated: 🔍

CVE: CVE-2016-4957 (🔍)
GCVE (CVE): GCVE-0-2016-4957
GCVE (VulDB): GCVE-100-87754

OVAL: 🔍

CERT: 🔍
SecurityFocus: 91010
SecurityTracker: 1036037

Misc.: 🔍
See also: 🔍

Entryinfo

Created: 06/06/2016 16:09
Updated: 01/27/2025 02:04
Changes: 06/06/2016 16:09 (79), 02/10/2019 11:47 (9), 01/27/2025 02:04 (18)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!