Can you get a password from a cookie?

Cookies are small text files that websites store on your computer to remember information about you and your preferences. Cookies can store a variety of data, including login information, shopping cart contents, and website settings. This leads many internet users to wonder – can hackers or malicious websites get your password from a cookie?

The short answer is no, you cannot directly get a user’s password from a cookie. Cookies do not actually store passwords in plain text. Instead, cookies store session IDs or authentication tokens that allow the website to recognize you without making you log in again every time you visit a new page. So while cookies may contain login credentials, the actual password is not present.

However, cookies are still a potential security concern. If a hacker managed to steal or access your cookies, they could potentially use the session ID stored in the cookie to access your account without knowing your password. Additionally, if you save your login credentials on a public or shared computer, someone else could use those stored cookies to access your accounts.

So you should still make efforts to protect your cookies and log out of websites when using public machines. But the good news is, the website itself cannot directly see or extract your password from the login or authentication cookies.

How websites use cookies for logins

When you visit a website, the following process allows you to login without entering your credentials every time:

1. You enter your username and password on the website’s login page.
2. The website checks your credentials and creates a session ID that is unique to you.
3. The session ID is stored in a cookie sent to your browser.
4. On other pages of the site, the cookie is sent along with requests to the server.
5. The server recognizes the session ID cookie and knows you are logged in.

So the cookie itself simply contains a random string of letters and numbers that the server associates with your account. Your actual password is not stored in the cookie.

The server also sets an expiration date for the session ID cookie, forcing you to eventually log in again even if you select “Remember Me.” This improves security in case someone else accesses your computer.

Can hackers guess passwords from cookies?

While the password is not directly present in the cookie, could a hacker still determine your password by analyzing the cookie?

The simple answer is no. Here are some key reasons why:

• Session IDs are long, random strings that have no relation to the actual password.
• Websites store password hashes on the server side, not the actual password.
• Cookies have expiration dates, limiting a hacker’s window to guess.
• Websites will lock accounts after too many login attempts.

Guessing passwords from hashes is considered practically impossible with modern hashing and encryption methods like bcrypt and SHA-256. Overall, the authentication architecture is designed so that session cookies themselves provide no clues about the user’s actual password.

Can you extract passwords from cookie files?

Your browser stores cookies in files on your hard drive. For example, Chrome browsers save cookies in a SQLite database file called Cookies. But these cookie files also do not contain your actual password for a couple reasons:

1. The login cookies only contain session IDs, not the password.
2. The SQLite database is encrypted using the Windows Data Protection API.

So even if a hacker managed to obtain the physical cookie files from your hard drive, they would not be able to extract your password or login credentials from the encrypted database.

Are cookies encrypted?

Cookies set using HTTPS are encrypted in transit between the browser and server using SSL/TLS encryption. However, cookies are stored in plain text on your local browser.

So on the server side, cookies are encrypted. But someone with local access to your computer could potentially read your cookies. This is why you should always logout of websites and clear cookies on public computers.

To help mitigate this, many modern browsers like Chrome isolate cookies on a per-site basis using key systems like HSTS. This helps minimize the impact if a malicious website tried to access cookies for other sites.

Can you steal cookies to hack accounts?

While cookies won’t directly contain a password, gaining access to someone’s login cookies can allow you to hijack their web sessions. This allows hackers to access user accounts without knowing their password.

Some ways hackers can steal cookies include:

• Using cross-site scripting (XSS) vulnerabilities to steal cookies
• Man-in-the-middle attacks on public WiFi
• Malware or spyware that extracts cookie files

Once a hacker has the session cookie, they can edit their own browser’s cookie store to insert the victim’s session ID. Then when they visit the site, they will be seamlessly logged in as the victim.

So while cookies don’t expose your actual password, cookie security remains critically important for account security. Make sure to be on guard against phishing attempts trying to trick you into accidentally disclosing your cookies.

Should cookies be used for logins?

While cookies themselves are generally secure, many experts argue session IDs and cookies should not be used for managing logins in the first place. Many modern websites and authentication standards like OAuth now use token-based authentication:

• You enter your credentials and are issued a time-limited JWT token.
• This token gets stored client-side and passed along with requests.
• The server verifies the signature and payload of the JWT token on each request.

This approach is considered more secure because:

• It eliminates reliance on cookie security.
• JWT tokens can only be generated by the server.
• Tokens contain embedded metadata like expiration time.

So while you can’t directly get a password from a cookie, the best practice is to avoid using cookies for managing logins to begin with. Token-based authentication is more robust and avoids many of the pitfalls of session cookies.

Conclusion

In summary, cookies themselves do not contain or expose a user’s actual password. Cookies store session IDs that allow sites to identify logged in users. While stealing cookies can allow hackers to hijack sessions, the authentication architecture is designed to never expose credentials like passwords directly.

Modern web developers should aim to replace cookie-based authentication with more secure token-based systems. However, cookies are still ubiquitous on the modern web. Understanding how websites use them provides key insight into improving your own security and privacy while browsing online. Be sure to logout and clear cookies when using public machines to minimize risks. With proper precautions, you can feel confident sensitive information like passwords are safe from prying eyes, even as cookies handle much of the web’s busy work to keep you logged in.