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In all Qualcomm products with Android releases from CAF using the Linux kernel, potential use after free scenarios and race conditions can occur when accessing global static variables without using a lock.
In all Qualcomm products with Android releases from CAF using the Linux kernel, potential use after free scenarios and race conditions can occur when accessing global static variables without using a lock.
CVSS 3.0 Base Score 4.7. CVSS Attack Vector: local. CVSS Attack Complexity: high. CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N).
CVSS 2.0 Base Score 2.6. CVSS Attack Vector: network. CVSS Attack Complexity: high. CVSS Vector: (AV:N/AC:H/Au:N/C:P/I:N/A:N).
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.
This code could be used in an e-commerce application that supports transfers between accounts. It takes the total amount of the transfer, sends it to the new account, and deducts the amount from the original account.
NotifyUser("New balance: $newbalance");FatalError("Bad Transfer Amount");FatalError("Insufficient Funds");A race condition could occur between the calls to GetBalanceFromDatabase() and SendNewBalanceToDatabase().
Suppose the balance is initially 100.00. An attack could be constructed as follows:
PROGRAM-2 sends a request to update the database, setting the balance to 99.00At this stage, the attacker should have a balance of 19.00 (due to 81.00 worth of transfers), but the balance is 99.00, as recorded in the database.
To prevent this weakness, the programmer has several options, including using a lock to prevent multiple simultaneous requests to the web application, or using a synchronization mechanism that includes all the code between GetBalanceFromDatabase() and SendNewBalanceToDatabase().
The following function attempts to acquire a lock in order to perform operations on a shared resource.
}
pthread_mutex_unlock(mutex);/* access shared resource */However, the code does not check the value returned by pthread_mutex_lock() for errors. If pthread_mutex_lock() cannot acquire the mutex for any reason, the function may introduce a race condition into the program and result in undefined behavior.
In order to avoid data races, correctly written programs must check the result of thread synchronization functions and appropriately handle all errors, either by attempting to recover from them or reporting it to higher levels.
}
return pthread_mutex_unlock(mutex);return result;/* access shared resource */Suppose a processor's Memory Management Unit (MMU) has 5 other shadow MMUs to distribute its workload for its various cores. Each MMU has the start address and end address of "accessible" memory. Any time this accessible range changes (as per the processor's boot status), the main MMU sends an update message to all the shadow MMUs.
Suppose the interconnect fabric does not prioritize such "update" packets over other general traffic packets. This introduces a race condition. If an attacker can flood the target with enough messages so that some of those attack packets reach the target before the new access ranges gets updated, then the attacker can leverage this scenario.
The following example demonstrates the weakness.
}free(buf3R2);The following code illustrates a use after free error:
}free(ptr);logError("operation aborted before commit", ptr);When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.
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