CVE-2022-23607 - URL Redirection to Untrusted Site ('Open Redirect')

Severity

74%

Complexity

27%

Confidentiality

66%

treq is an HTTP library inspired by requests but written on top of Twisted's Agents. Treq's request methods (`treq.get`, `treq.post`, etc.) and `treq.client.HTTPClient` constructor accept cookies as a dictionary. Such cookies are not bound to a single domain, and are therefore sent to *every* domain ("supercookies"). This can potentially cause sensitive information to leak upon an HTTP redirect to a different domain., e.g. should `https://example.com` redirect to `http://cloudstorageprovider.com` the latter will receive the cookie `session`. Treq 2021.1.0 and later bind cookies given to request methods (`treq.request`, `treq.get`, `HTTPClient.request`, `HTTPClient.get`, etc.) to the origin of the *url* parameter. Users are advised to upgrade. For users unable to upgrade Instead of passing a dictionary as the *cookies* argument, pass a `http.cookiejar.CookieJar` instance with properly domain- and scheme-scoped cookies in it.

CVSS 3.1 Base Score 7.4. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N).

CVSS 2.0 Base Score 4.3. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:N/A:N).

Demo Examples

URL Redirection to Untrusted Site ('Open Redirect')

CWE-601

The following code obtains a URL from the query string and then redirects the user to that URL.


               
header("Location: " . $redirect_url);

The problem with the above code is that an attacker could use this page as part of a phishing scam by redirecting users to a malicious site. For example, assume the above code is in the file example.php. An attacker could supply a user with the following link:


               
http://example.com/example.php?url=http://malicious.example.com

The user sees the link pointing to the original trusted site (example.com) and does not realize the redirection that could take place.

URL Redirection to Untrusted Site ('Open Redirect')

CWE-601

The following code is a Java servlet that will receive a GET request with a url parameter in the request to redirect the browser to the address specified in the url parameter. The servlet will retrieve the url parameter value from the request and send a response to redirect the browser to the url address.


               
}
}
}
response.sendRedirect(url);

The problem with this Java servlet code is that an attacker could use the RedirectServlet as part of a e-mail phishing scam to redirect users to a malicious site. An attacker could send an HTML formatted e-mail directing the user to log into their account by including in the e-mail the following link:


               
<a href="http://bank.example.com/redirect?url=http://attacker.example.net">Click here to log in</a>

The user may assume that the link is safe since the URL starts with their trusted bank, bank.example.com. However, the user will then be redirected to the attacker's web site (attacker.example.net) which the attacker may have made to appear very similar to bank.example.com. The user may then unwittingly enter credentials into the attacker's web page and compromise their bank account. A Java servlet should never redirect a user to a URL without verifying that the redirect address is a trusted site.

Demo Examples

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

The following code checks validity of the supplied username and password and notifies the user of a successful or failed login.


               
}
}
print "Login Successful";
print "Login Failed - incorrect password";
print "Login Failed - unknown username";

In the above code, there are different messages for when an incorrect username is supplied, versus when the username is correct but the password is wrong. This difference enables a potential attacker to understand the state of the login function, and could allow an attacker to discover a valid username by trying different values until the incorrect password message is returned. In essence, this makes it easier for an attacker to obtain half of the necessary authentication credentials.

While this type of information may be helpful to a user, it is also useful to a potential attacker. In the above example, the message for both failed cases should be the same, such as:


               
"Login Failed - incorrect username or password"

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code tries to open a database connection, and prints any exceptions that occur.


               
}
openDbConnection();
//print exception message that includes exception message and configuration file location
echo 'Check credentials in config file at: ', $Mysql_config_location, '\n';

If an exception occurs, the printed message exposes the location of the configuration file the script is using. An attacker can use this information to target the configuration file (perhaps exploiting a Path Traversal weakness). If the file can be read, the attacker could gain credentials for accessing the database. The attacker may also be able to replace the file with a malicious one, causing the application to use an arbitrary database.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

In the example below, the method getUserBankAccount retrieves a bank account object from a database using the supplied username and account number to query the database. If an SQLException is raised when querying the database, an error message is created and output to a log file.


               
}
return userAccount;
}
userAccount = (BankAccount)queryResult.getObject(accountNumber);
Logger.getLogger(BankManager.class.getName()).log(Level.SEVERE, logMessage, ex);

The error message that is created includes information about the database query that may contain sensitive information about the database or query logic. In this case, the error message will expose the table name and column names used in the database. This data could be used to simplify other attacks, such as SQL injection (CWE-89) to directly access the database.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code stores location information about the current user:


               
}...
Log.e("ExampleActivity", "Caught exception: " + e + " While on User:" + User.toString());

When the application encounters an exception it will write the user object to the log. Because the user object contains location information, the user's location is also written to the log.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

The following is an actual MySQL error statement:


               
Warning: mysql_pconnect(): Access denied for user: 'root@localhost' (Using password: N1nj4) in /usr/local/www/wi-data/includes/database.inc on line 4

The error clearly exposes the database credentials.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code displays some information on a web page.


               
Social Security Number: <%= ssn %></br>Credit Card Number: <%= ccn %>

The code displays a user's credit card and social security numbers, even though they aren't absolutely necessary.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

The following program changes its behavior based on a debug flag.


               
} %>

The code writes sensitive debug information to the client browser if the "debugEnabled" flag is set to true .

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code uses location to determine the user's current US State location.

First the application must declare that it requires the ACCESS_FINE_LOCATION permission in the application's manifest.xml:


               
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

During execution, a call to getLastLocation() will return a location based on the application's location permissions. In this case the application has permission for the most accurate location possible:


               
deriveStateFromCoords(userCurrLocation);

While the application needs this information, it does not need to use the ACCESS_FINE_LOCATION permission, as the ACCESS_COARSE_LOCATION permission will be sufficient to identify which US state the user is in.

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