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An information disclosure vulnerability exists in Microsoft SharePoint when an attacker uploads a specially crafted file to the SharePoint Server.An authenticated attacker who successfully exploited this vulnerability could potentially leverage SharePoint functionality to obtain SMB hashes.The security update addresses the vulnerability by correcting how SharePoint checks file content., aka 'Microsoft SharePoint Information Disclosure Vulnerability'.
An information disclosure vulnerability exists in Microsoft SharePoint when an attacker uploads a specially crafted file to the SharePoint Server.An authenticated attacker who successfully exploited this vulnerability could potentially leverage SharePoint functionality to obtain SMB hashes.The security update addresses the vulnerability by correcting how SharePoint checks file content., aka 'Microsoft SharePoint Information Disclosure Vulnerability'.
CVSS 3.1 Base Score 6.5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).
CVSS 2.0 Base Score 4. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:S/C:P/I:N/A:N).
The following code intends to allow a user to upload a picture to the web server. The HTML code that drives the form on the user end has an input field of type "file".
</form>Once submitted, the form above sends the file to upload_picture.php on the web server. PHP stores the file in a temporary location until it is retrieved (or discarded) by the server side code. In this example, the file is moved to a more permanent pictures/ directory.
}// Define the target location where the picture being// uploaded is going to be saved.// Move the uploaded file to the new location.echo "The picture has been successfully uploaded.";echo "There was an error uploading the picture, please try again.";The problem with the above code is that there is no check regarding type of file being uploaded. Assuming that pictures/ is available in the web document root, an attacker could upload a file with the name:
malicious.phpSince this filename ends in ".php" it can be executed by the web server. In the contents of this uploaded file, the attacker could use:
?>system($_GET['cmd']);Once this file has been installed, the attacker can enter arbitrary commands to execute using a URL such as:
http://server.example.com/upload_dir/malicious.php?cmd=ls%20-lwhich runs the "ls -l" command - or any other type of command that the attacker wants to specify.
The following code demonstrates the unrestricted upload of a file with a Java servlet and a path traversal vulnerability. The HTML code is the same as in the previous example with the action attribute of the form sending the upload file request to the Java servlet instead of the PHP code.
</form>When submitted the Java servlet's doPost method will receive the request, extract the name of the file from the Http request header, read the file contents from the request and output the file to the local upload directory.
}
{...}
// output successful upload response HTML page
bw.close();}bw.flush();...As with the previous example this code does not perform a check on the type of the file being uploaded. This could allow an attacker to upload any executable file or other file with malicious code.
Additionally, the creation of the BufferedWriter object is subject to relative path traversal (CWE-22, CWE-23). Depending on the executing environment, the attacker may be able to specify arbitrary files to write to, leading to a wide variety of consequences, from code execution, XSS (CWE-79), or system crash.
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"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 locationecho '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.
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.
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.
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 4The error clearly exposes the database credentials.
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.
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 .
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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