ISC BIND Dynamically Loadable Zones Unauthorized Access Vulnerability [CVE-2019-6465]
CVE Number – CVE-2019-6465
A vulnerability in ISC BIND could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive information from a targeted system.
The vulnerability is due to improper zone transfer controls that are applied on writable Dynamically Loadable Zones (DLZs) by the affected software. An attacker could exploit this vulnerability to request and receive a zone transfer of a DLZ from a targeted DNS server. A successful exploit could be used to conduct further attacks.
ISC.org has confirmed the vulnerability and released software updates.
Analysis
- To exploit this vulnerability, an attacker must send a request to the targeted DNS server, making exploitation more difficult in environments that restrict network access from untrusted sources.
Safeguards
- 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.org has released a security advisory at the following link: CVE-2019-6465: Zone transfer controls for writable DLZ zones were not effective
Fixed Software
- ISC.org has released software updates at the following link: BIND 9.11.5-P4 and BIND 9.12.3-P4
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.