CVE-2014-3209 in ldns
Summary
by MITRE
The ldns-keygen tool in ldns 1.6.x uses the current umask to set the privileges of the private key, which might allow local users to obtain the private key by reading the file.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/04/2022
The ldns-keygen tool in ldns version 1.6.x contains a critical security flaw that stems from improper file permission handling during private key generation. This vulnerability resides in the tool's implementation where it relies on the current umask value to determine the access permissions for generated private key files. The umask, which is a system setting that controls default file permissions for newly created files, is being directly utilized without proper validation or override mechanisms. When ldns-keygen creates private key files, it inherits the umask settings from the executing process, potentially allowing unauthorized local users to access these sensitive cryptographic materials through read operations on the key files.
This vulnerability represents a classic example of improper privilege management and weak file access control, aligning with CWE-732: Incorrect Permission Assignment for Critical Resource. The flaw enables local privilege escalation scenarios where attackers can exploit the system's default umask settings to gain unauthorized access to private keys that should remain protected. The security implications extend beyond simple file access, as private keys are fundamental components of cryptographic systems that protect sensitive communications and authentication mechanisms. When these keys become accessible to unauthorized users, it compromises the entire security infrastructure that relies on their confidentiality.
The operational impact of this vulnerability is significant for systems utilizing ldns-keygen for DNS security key management, particularly in environments where multiple users share the same system or where umask settings are not properly configured. Attackers can exploit this weakness by setting a permissive umask value before executing ldns-keygen, thereby creating private key files with overly broad read permissions. This vulnerability affects any system where ldns-keygen is used to generate DNSSEC keys, including DNS servers, certificate authorities, and other cryptographic infrastructure components. The flaw is particularly dangerous in multi-tenant environments or shared hosting scenarios where different users may have varying levels of access to the same system resources.
Mitigation strategies for this vulnerability involve several approaches that address both immediate remediation and long-term security hardening. The most effective immediate solution is to upgrade to a patched version of ldns that properly sets secure file permissions for private key files, independent of the system umask. System administrators should also implement proper umask configuration management, ensuring that umask values are set to restrictive settings before executing cryptographic tools. Additionally, implementing file access control lists and monitoring for unauthorized file access attempts can provide additional layers of defense. Organizations should follow security best practices outlined in the NIST SP 800-53 security controls and consider implementing the ATT&CK technique T1078.004: Valid Accounts, which emphasizes the importance of proper access control and privilege management. Regular security auditing and key rotation procedures should also be implemented to minimize the impact of potential compromise.