PowerDNS Authoritative Server HTTP Request Input Validation Vulnerability [CVE-2019-3871]
CVE Number – CVE-2019-3871
A vulnerability in PowerDNS Authoritative Server could allow an authenticated, remote attacker to cause a denial of service (DoS) condition, access sensitive information, or conduct a spoofing attack on a targeted system.
The vulnerability is due to insufficient validation of user-supplied input by the affected software when the HTTP remote backend is used in RESTful mode. An attacker could exploit this vulnerability by sending an HTTP request that submits malicious input to the targeted system. A successful exploit could allow the attacker to cause a DoS condition, access sensitive information, or conduct a spoofing attack.Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available.PowerDNS has confirmed the vulnerability and released software updates.
Analysis
- 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.
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
- PowerDNS has released a bug report and a security advisory at the following links: Bug #7573 and PowerDNS Security Advisory 2019-03: Insufficient validation in the HTTP remote backend
Fixed Software
- PowerDNS has released software updates at the following link: PowerDNS Authoritative Server 4.0.7 and 4.1.7
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.