Description

Cleartext storage of sensitive information in Windows Hello allows an authorized attacker to perform tampering locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.5",
  "pubDate": "2026-08-11T17:18:15.603Z",
  "pubdate": "2026-08-11T17:18:15.603Z",
  "executiveSummary": "This vulnerability involves the cleartext storage of sensitive information within Windows Hello, posing a significant risk to system integrity and data confidentiality. The primary vulnerability type is cleartext storage of sensitive information, which directly leads to local tampering vulnerabilities. The affected product is Windows Hello. The risk implications are severe, as unauthorized manipulation of sensitive data stored in cleartext can compromise authentication mechanisms and undermine the cryptographic trust boundaries established by the operating system. The attacker capabilities required for successful exploitation necessitate local access to the target system. Furthermore, the attacker must already possess authorization or appropriate local execution privileges to interact with the vulnerable component and execute tampering operations. Exploitation requirements mandate that the adversary is positioned locally on the host, enabling direct access to the storage mechanisms utilized by Windows Hello where sensitive data resides unencrypted. Because the information is stored without obfuscation or cryptographic protection, an adversary with local access can inspect, modify, or replace the cleartext data structures at rest. This structural weakness bypasses intended security controls and permits unauthorized local tampering, potentially facilitating downstream security degradation or unauthorized state manipulation within the authentication subsystem.",
  "technicalDetails": "The root cause of the vulnerability stems from the insecure implementation of data persistence within Windows Hello, specifically the practice of writing sensitive information in cleartext to local storage mediums. The vulnerable component is the internal data handling and storage subsystem of Windows Hello responsible for persisting operational data or state information. Due to the absence of encryption, hashing, or secure serialization practices, sensitive artifacts remain in an unencrypted format accessible via standard file system or registry interrogation APIs. Exploitation occurs entirely locally, requiring the attacker to possess prior local access to the system, along with sufficient privileges to read and write to the specific storage locations utilized by Windows Hello. The attack flow proceeds through distinct phases: reconnaissance, where the attacker identifies the storage locations of the cleartext sensitive information; direct access, wherein the attacker navigates to the file paths or registry keys containing the unencrypted data; and tampering execution, where the attacker modifies, injects, or replaces the cleartext content with malicious or crafted payloads. Since the system trusts the integrity of the stored data without performing cryptographic validation or integrity checks during retrieval, the modified cleartext information is subsequently processed by Windows Hello during standard operational routines. This payload behavior results in unauthorized state tampering, logic corruption, or anomalous subsystem behavior. The post-exploitation impact includes the potential undermining of local security assurances, unauthorized manipulation of authentication-related artifacts, and sustained local tampering capabilities. The lack of cryptographic safeguards ensures that no complex decryption routines are required by the attacker, lowering the barrier for successful local tampering once initial host access is achieved."
}