CVE-2024-7594 in Vault
Summary
by MITRE • 09/26/2024
Vault’s SSH secrets engine did not require the valid_principals list to contain a value by default. If the valid_principals and default_user fields of the SSH secrets engine configuration are not set, an SSH certificate requested by an authorized user to Vault’s SSH secrets engine could be used to authenticate as any user on the host. Fixed in Vault Community Edition 1.17.6, and in Vault Enterprise 1.17.6, 1.16.10, and 1.15.15.
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Analysis
by VulDB Data Team • 08/08/2025
The vulnerability identified as CVE-2024-7594 resides within HashiCorp Vault's SSH secrets engine implementation, representing a critical authorization bypass flaw that undermines the security controls designed to restrict SSH access. This issue specifically affects the validation mechanisms within Vault's SSH certificate generation process where the system fails to enforce mandatory principal validation when certain configuration parameters are left unset. The vulnerability manifests when the valid_principals and default_user fields are not explicitly configured, creating a dangerous default state that allows unauthorized privilege escalation. This flaw directly contravenes security best practices by permitting any authenticated user to request certificates that can authenticate as arbitrary users on target systems, effectively eliminating the intended access controls that should limit SSH authentication to predefined authorized principals.
The technical root cause of this vulnerability stems from the improper handling of default configuration values within Vault's SSH secrets engine. When administrators fail to explicitly define the valid_principals parameter, the system defaults to a permissive state where certificate requests are not validated against a specific list of authorized users. This creates a scenario where an attacker who has legitimate access to request SSH certificates through Vault can exploit this misconfiguration to generate certificates that bypass the intended user restrictions. The flaw operates at the configuration validation layer, where the system should enforce mandatory parameter settings but instead allows a dangerous default behavior. According to CWE classification, this represents a weakness in the design of access control mechanisms, specifically CWE-284: Improper Access Control, and more specifically CWE-285: Improper Authorization. The vulnerability aligns with ATT&CK technique T1552.001: Unsecured Credentials - Credentials in Files, as it allows for the creation of unauthorized credentials that can be used to access systems with elevated privileges.
The operational impact of CVE-2024-7594 is severe and far-reaching, particularly in environments where Vault serves as a central credential management system for SSH access. An attacker exploiting this vulnerability can effectively bypass the principle of least privilege by generating SSH certificates that authenticate as any user configured on target systems, potentially gaining access to sensitive resources, escalating privileges, or conducting lateral movement within the network. This vulnerability is particularly dangerous because it can be exploited silently without detection, as the default configuration behavior appears legitimate to system administrators who may not realize that the security controls are not properly enforced. The risk is compounded by the fact that this vulnerability affects multiple versions of Vault, including both Community and Enterprise editions, meaning that a significant portion of Vault installations could be exposed to this attack vector. Organizations relying on Vault for SSH certificate management face potential data breaches, unauthorized access to critical systems, and violations of compliance requirements that mandate proper access controls and audit trails.
Mitigation of CVE-2024-7594 requires immediate action to configure the SSH secrets engine with proper principal validation settings. Administrators must explicitly define the valid_principals parameter in their SSH secrets engine configuration to ensure that only authorized users can be authenticated through Vault-generated certificates. The recommended approach involves setting the valid_principals field to contain a specific list of authorized usernames or user groups that should be permitted to authenticate using certificates issued by Vault. Additionally, organizations should implement comprehensive monitoring and alerting around SSH certificate issuance activities to detect any unauthorized configuration changes. The fix requires updating Vault to the patched versions mentioned in the advisory, specifically Vault Community Edition 1.17.6 and Enterprise editions 1.17.6, 1.16.10, and 1.15.15. Security teams should conduct thorough audits of their SSH secrets engine configurations to ensure that all instances have proper principal validation enabled and that default configurations are reviewed and hardened according to security best practices. Regular security assessments of credential management systems should include verification that access control mechanisms are properly enforced and that default behaviors do not introduce security vulnerabilities.