NTPsec ntp_control.c NULL Pointer Dereference Denial of Service Vulnerability [CVE-2019-6445]

CVE Number – CVE-2019-6445

A vulnerability in NTPsec could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.

The vulnerability is due to a NULL pointer dereference condition that could occur in the ntp_control.csource code file of the affected software. An attacker could exploit this vulnerability by making a call to the ctl_getitem function to set a value to NULL that is later dereferenced. An exploit could cause the ntpd daemon on the targeted system to crash, resulting in a DoS condition. 

Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available. 

The NTPsec project has confirmed the vulnerability and released software updates.


  • To exploit this vulnerability, the attacker must have user-level access to the targeted system. This access requirement could reduce the likelihood of a successful exploit.


  • Administrators are advised to apply the appropriate updates.

    Administrators are advised to allow only trusted users to have network access.

    Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.

    Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.

    Administrators can help protect affected systems from external attacks by using a solid firewall strategy.

    Administrators are advised to monitor affected systems.

Vendor Announcements

  • The NTPsec project has released a changelog at the following link: NTPsec_1_1_3/NEWS

Fixed Software

  • The NTPsec project has released software updates at the following link: NTPsec_1_1_3

Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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