CVE-2021-38554 in Vault
Summary
by MITRE • 08/14/2021
HashiCorp Vault and Vault Enterprise’s UI erroneously cached and exposed user-viewed secrets between sessions in a single shared browser. Fixed in 1.8.0 and pending 1.7.4 / 1.6.6 releases.
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Analysis
by VulDB Data Team • 08/18/2021
HashiCorp Vault and Vault Enterprise suffered from a critical information disclosure vulnerability that allowed unauthorized access to sensitive data through improper session management and caching mechanisms. This vulnerability specifically affected the user interface components of the software, creating a scenario where secrets viewed by users remained accessible across different browser sessions when using a single shared browser instance. The flaw existed in the web application's handling of cached data and session state management, which failed to properly isolate user contexts and clear sensitive information from memory or browser cache after user interactions.
The technical implementation of this vulnerability stemmed from inadequate memory management practices within the Vault UI's data handling architecture. When users accessed and viewed secrets through the web interface, the application cached this information in browser memory or local storage without proper sanitization between user sessions. This caching behavior violated fundamental security principles for multi-user environments where session isolation is critical. The vulnerability was particularly concerning because it operated at the application layer, affecting the user-facing components rather than underlying cryptographic or network protocols, making it more accessible to attackers who could exploit it through standard browser-based interactions.
The operational impact of this vulnerability extended beyond simple data exposure to potentially compromise entire security infrastructures. Organizations relying on Vault for secret management faced significant risks when multiple users shared browser sessions or when administrators accessed the UI from shared workstations. The exposure of cached secrets could lead to unauthorized access to sensitive credentials, API keys, certificates, and other confidential data that should remain isolated to individual user sessions. This vulnerability particularly affected environments where security compliance was paramount, as it could result in violations of data protection regulations and security frameworks that mandate proper access controls and session isolation.
Mitigation strategies for this vulnerability required immediate deployment of patched versions of Vault software, with the fix implemented in versions 1.8.0 and subsequent releases. Organizations needed to ensure all instances of Vault were upgraded to prevent further exposure of cached secrets. Additionally, security teams should implement enhanced monitoring for unauthorized access patterns and conduct thorough security assessments of their Vault deployments. The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and relates to ATT&CK technique T1552.001 for unsecured credentials and T1071.004 for application layer protocols. Organizations should also consider implementing additional access controls and session management policies to minimize the risk of similar vulnerabilities in other applications and ensure proper isolation of user contexts across shared environments.