CVE-2018-19786 in Vault
Summary
by MITRE
HashiCorp Vault before 1.0.0 writes the master key to the server log in certain unusual or misconfigured scenarios in which incorrect data comes from the autoseal mechanism without an error being reported.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/17/2020
HashiCorp Vault version 1.0.0 and earlier contains a critical security flaw that exposes master key material in server logs under specific misconfiguration scenarios. This vulnerability arises from the autoseal mechanism's failure to properly validate data integrity, resulting in the inadvertent logging of sensitive cryptographic material when unexpected data is received from the autoseal backend. The flaw represents a significant bypass of the cryptographic protection mechanisms that Vault is designed to enforce, as it allows unauthorized parties who gain access to server logs to obtain the master key that protects all vaulted secrets. The vulnerability is particularly concerning because it operates silently without generating error messages, meaning administrators may remain unaware of the exposure until it's too late. This issue directly relates to CWE-209, which addresses the exposure of sensitive information through error messages, and also aligns with CWE-312, concerning the exposure of sensitive data through log files. The operational impact extends beyond simple data exposure, as the master key compromise enables full decryption of all secrets stored within the vault, effectively nullifying the cryptographic security posture. Attackers could leverage this vulnerability to gain unauthorized access to sensitive data including API keys, passwords, certificates, and other confidential information that organizations rely on Vault to protect. The vulnerability is particularly dangerous in environments where server logs are not properly secured or where log access is not strictly controlled, as it provides a direct path to decrypt all vaulted secrets. Organizations using older Vault versions should immediately implement mitigations including upgrading to version 1.0.0 or later, implementing strict log access controls, and conducting thorough audits of their vault configurations. Additionally, security teams should monitor for unusual autoseal behavior and implement proper error handling to ensure that such silent failures do not occur. The ATT&CK framework categorizes this vulnerability under T1552.001, which covers the technique of "Unsecured Credentials," as it involves the exposure of cryptographic keys through insecure logging practices. This vulnerability demonstrates the critical importance of proper input validation and error handling in cryptographic systems, where failure to validate data integrity can lead to complete system compromise. The flaw underscores the necessity of robust logging security practices and the potential for seemingly minor configuration issues to create significant security breaches in enterprise security infrastructure.