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MITRE ATT&CK · T1555.003

Credentials from Web Browsers

MITRE · cited in 7 of our lessons

Explanation

What attackers do. Attackers read saved passwords, cookies and other secrets stored by web browsers, usually by extracting browser data files and decrypting them. Infostealer malware relies heavily on this. It serves the Credential Access tactic.

How to defend. Use an enterprise password manager and disable browser password saving through policy where suitable. Keep browsers updated, since newer protections make extraction harder, and stop infostealers with endpoint protection. Use phishing-resistant MFA so stolen passwords are less useful.

Signs to look for. Look for non-browser processes accessing browser profile databases, archives of browser data created in temp folders, and logins with credentials known to be saved in browsers. A common gap is personal browser profiles on corporate devices that sync corporate passwords to unmanaged accounts.

Open the technique on MITRE ATT&CK
The official text
Adversaries may acquire credentials from web browsers by reading files specific to the target browser. Web browsers commonly save credentials such as website usernames and passwords so that they do not need to be entered manually in the future. Web browsers typically store the credentials in an encrypted format within a credential store; however, methods exist to extract plaintext credentials from web browsers. For example, on Windows systems, encrypted credentials may be obtained from Google Chrome by reading a database file, `AppData\Local\Google\Chrome\User Data\Default\Login Data` and executing a SQL query: `SELECT action_url, username_value, password_value FROM logins;`. The plaintext password can then be obtained by passing the encrypted credentials to the Windows API function `CryptUnprotectData`, which uses the victim’s cached logon credentials as the decryption key. Adversaries have executed similar procedures for common web browsers such as FireFox, Safari, Edge, etc. Windows stores Internet Explorer and Microsoft Edge credentials in Credential Lockers managed by the Windows Credential Manager.

© The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation (MITRE ATT&CK®).

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