CVE-2018-11747 in Puppet Discovery
Summary
by MITRE
Previously, Puppet Discovery was shipped with a default generated TLS certificate in the nginx container. In version 1.4.0, a unique certificate will be generated on installation or the user will be able to provide their own TLS certificate for ingress.
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Analysis
by VulDB Data Team • 05/17/2020
The vulnerability described in CVE-2018-11747 relates to a critical security flaw in Puppet Discovery's implementation of TLS certificate management within its nginx container deployment. This issue represents a significant weakness in the software's default security configuration, as it shipped with a hardcoded default TLS certificate that could be easily identified and exploited by malicious actors. The vulnerability stems from the insecure practice of using a universally known default certificate, which violates fundamental security principles of unique credential generation and proper key management. This flaw falls under the category of weak cryptographic key generation as classified by CWE-326, where the system fails to implement proper randomization and uniqueness in certificate creation. The default certificate in question would have been included in various threat intelligence feeds and could be readily recognized by attackers during reconnaissance phases, effectively providing them with a known entry point into the system.
The technical implementation of this vulnerability occurs within the nginx container that Puppet Discovery utilizes for ingress traffic management. When the software was installed without explicit TLS certificate configuration, it automatically deployed a certificate that was not unique to the specific installation environment. This default certificate would typically be a well-known value that could be found in public repositories or security databases, making the entire system vulnerable to man-in-the-middle attacks and unauthorized access attempts. The flaw represents a failure in the principle of least privilege and secure by default configurations, as the system did not enforce proper certificate uniqueness or cryptographic strength during the installation process. This vulnerability directly enables several attack vectors defined in the MITRE ATT&CK framework under T1071.004 for Application Layer Protocol: DNS and T1046 for Network Service Scanning, as attackers could exploit the predictable certificate to gain insights into the target environment.
The operational impact of this vulnerability extends beyond simple credential exposure, as it fundamentally undermines the trust model that TLS is designed to establish between communicating parties. Organizations deploying Puppet Discovery without addressing this default certificate issue would have their entire infrastructure exposed to potential compromise, particularly during initial connection establishment and certificate validation phases. The vulnerability could enable attackers to perform session hijacking, data interception, and unauthorized access to configuration management systems that rely on Puppet Discovery for orchestration. This represents a critical weakness in enterprise security infrastructure, as Puppet Discovery is commonly used for managing and automating system configurations across large networks, making the compromise of its TLS layer potentially devastating to overall network security posture. The impact is particularly severe because the default certificate would likely be recognized across multiple installations, creating a scalable attack vector that could affect numerous organizations simultaneously.
Organizations should immediately implement mitigations that align with industry best practices for secure configuration management and cryptographic key handling. The recommended approach involves either generating unique certificates during the Puppet Discovery installation process or manually providing custom TLS certificates that are properly secured and unique to each deployment environment. This remediation addresses the core issue by ensuring that each installation uses cryptographic material that cannot be easily predicted or replicated by attackers. The solution should incorporate proper certificate lifecycle management practices, including key rotation and secure storage mechanisms. Organizations should also implement monitoring and alerting for certificate-related activities, as outlined in the NIST Cybersecurity Framework and ISO 27001 standards for cryptographic key management. The mitigation strategy should include verifying that the generated certificates meet minimum security requirements for key size and cryptographic algorithm strength, typically requiring at least 2048-bit RSA keys or equivalent elliptic curve cryptography. Additionally, implementing certificate pinning and proper certificate validation procedures will further strengthen the security posture against this and similar vulnerabilities.