ISC BIND managed-keys Trust Anchor Denial of Service Vulnerability [CVE-2018-5745]

CVE Number – CVE-2018-5745

A vulnerability in the managed-keys feature of ISC BIND could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.

The vulnerability is due to an assertion failure that could occur in the managed-keys feature of the affected software if trust anchor keys are replaced with keys that use an unsupported algorithm during key rollover. An attacker could exploit this vulnerability to cause the named daemon to crash. A successful exploit could result in a DoS condition. 

ISC has confirmed the vulnerability and released software updates.


  • To exploit this vulnerability, the attacker must have administrative-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

  • ISC has released a security advisory at the following link: CVE-2018-5745

Fixed Software

  • ISC has released software updates at the following link: BIND 9.11.5-P4 and 9.12.3-P4. BIND 9.11.5-S5 is available for eligible ISC support customers.

Jason Davies

UK based technology professional, with an interest in computer security and telecoms.

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