CVE-2019-6469 : Exploit Details and Defense Strategies
Discover the impact of CVE-2019-6469, a vulnerability in BIND 9 Supported Preview Edition. Learn about the affected versions, exploitation mechanism, and mitigation steps.
A vulnerability in the EDNS Client Subnet (ECS) functionality of BIND 9 Supported Preview Edition could lead to BIND terminating unexpectedly due to an assertion failure. This CVE was published on May 29, 2019, by ISC.
Understanding CVE-2019-6469
This CVE affects BIND 9 Supported Preview Edition, specifically versions 9.10.5-S1 through 9.11.6-S1. The issue arises when handling responses containing improperly formatted RRSIGs.
What is CVE-2019-6469?
The presence of a vulnerability in the ECS feature of recursive resolvers can cause BIND to exit unexpectedly due to an assertion failure when processing responses with malformed RRSIGs.
The Impact of CVE-2019-6469
- CVSS Score: 5.9 (Medium Severity)
- Attack Vector: Network
- Attack Complexity: High
- Availability Impact: High
- No impact on Confidentiality or Integrity
- No privileges required
- No user interaction required
Technical Details of CVE-2019-6469
This section provides detailed technical information about the vulnerability.
Vulnerability Description
An attacker can exploit this vulnerability by causing a server to perform a query that triggers an assertion failure when the response contains malformed RRSIGs.
Affected Systems and Versions
- Product: BIND 9 Supported Preview Edition
- Vendor: ISC
- Versions: BIND 9.10.5-S1 -> 9.11.6-S1
Exploitation Mechanism
- Attackers can deliberately cause a server to exit by sending queries with malformed RRSIGs while using the recursive ECS feature.
Mitigation and Prevention
It is crucial to take immediate steps to mitigate the impact of CVE-2019-6469.
Immediate Steps to Take
- Upgrade to BIND 9.11.7-S1 or a patched release closest to your current version.
- Disable ECS options in the server's configuration to prevent exploitation.
Long-Term Security Practices
- Regularly update BIND to the latest version to address security vulnerabilities.
- Implement network security measures to detect and prevent malicious activities.
Patching and Updates
- Ensure that BIND is regularly patched and updated to the latest secure version.