36%
39%
81%
Multiple integer overflows in TrueCrypt 7.1a allow local users to (1) obtain sensitive information via vectors involving a crafted item->OriginalLength value in the MainThreadProc function in EncryptedIoQueue.c or (2) cause a denial of service (memory consumption) via vectors involving large StartingOffset and Length values in the ProcessVolumeDeviceControlIrp function in Ntdriver.c.
Multiple integer overflows in TrueCrypt 7.1a allow local users to (1) obtain sensitive information via vectors involving a crafted item->OriginalLength value in the MainThreadProc function in EncryptedIoQueue.c or (2) cause a denial of service (memory consumption) via vectors involving large StartingOffset and Length values in the ProcessVolumeDeviceControlIrp function in Ntdriver.c.
CVSS 3.0 Base Score 7.1. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H).
CVSS 2.0 Base Score 3.6. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (AV:L/AC:L/Au:N/C:P/I:N/A:P).
The following image processing code allocates a table for images.
...This code intends to allocate a table of size num_imgs, however as num_imgs grows large, the calculation determining the size of the list will eventually overflow (CWE-190). This will result in a very small list to be allocated instead. If the subsequent code operates on the list as if it were num_imgs long, it may result in many types of out-of-bounds problems (CWE-119).
The following code excerpt from OpenSSH 3.3 demonstrates a classic case of integer overflow:
}for (i = 0; i < nresp; i++) response[i] = packet_get_string(NULL);If nresp has the value 1073741824 and sizeof(char*) has its typical value of 4, then the result of the operation nresp*sizeof(char*) overflows, and the argument to xmalloc() will be 0. Most malloc() implementations will happily allocate a 0-byte buffer, causing the subsequent loop iterations to overflow the heap buffer response.
Integer overflows can be complicated and difficult to detect. The following example is an attempt to show how an integer overflow may lead to undefined looping behavior:
}bytesRec += getFromInput(buf+bytesRec);In the above case, it is entirely possible that bytesRec may overflow, continuously creating a lower number than MAXGET and also overwriting the first MAXGET-1 bytes of buf.
In this example the method determineFirstQuarterRevenue is used to determine the first quarter revenue for an accounting/business application. The method retrieves the monthly sales totals for the first three months of the year, calculates the first quarter sales totals from the monthly sales totals, calculates the first quarter revenue based on the first quarter sales, and finally saves the first quarter revenue results to the database.
}
return 0;// Variable for sales revenue for the quarter// Calculate quarterly total// Calculate the total revenue for the quarterHowever, in this example the primitive type short int is used for both the monthly and the quarterly sales variables. In C the short int primitive type has a maximum value of 32768. This creates a potential integer overflow if the value for the three monthly sales adds up to more than the maximum value for the short int primitive type. An integer overflow can lead to data corruption, unexpected behavior, infinite loops and system crashes. To correct the situation the appropriate primitive type should be used, as in the example below, and/or provide some validation mechanism to ensure that the maximum value for the primitive type is not exceeded.
}
...// Calculate quarterly total// Calculate the total revenue for the quarterNote that an integer overflow could also occur if the quarterSold variable has a primitive type long but the method calculateRevenueForQuarter has a parameter of type short.
The following example demonstrates the weakness.
}
}
}...
Thread.currentThread().interrupt();// postpone response...
new Thread(loop).start();
}
}}r.run();...There are no limits to runnables. Potentially an attacker could cause resource problems very quickly.
This code allocates a socket and forks each time it receives a new connection.
}pid = fork();The program does not track how many connections have been made, and it does not limit the number of connections. Because forking is a relatively expensive operation, an attacker would be able to cause the system to run out of CPU, processes, or memory by making a large number of connections. Alternatively, an attacker could consume all available connections, preventing others from accessing the system remotely.
In the following example a server socket connection is used to accept a request to store data on the local file system using a specified filename. The method openSocketConnection establishes a server socket to accept requests from a client. When a client establishes a connection to this service the getNextMessage method is first used to retrieve from the socket the name of the file to store the data, the openFileToWrite method will validate the filename and open a file to write to on the local file system. The getNextMessage is then used within a while loop to continuously read data from the socket and output the data to the file until there is no longer any data from the socket.
}
closeSocket(socket);return(FAIL);
closeFile();
}
break;This example creates a situation where data can be dumped to a file on the local file system without any limits on the size of the file. This could potentially exhaust file or disk resources and/or limit other clients' ability to access the service.
In the following example, the processMessage method receives a two dimensional character array containing the message to be processed. The two-dimensional character array contains the length of the message in the first character array and the message body in the second character array. The getMessageLength method retrieves the integer value of the length from the first character array. After validating that the message length is greater than zero, the body character array pointer points to the start of the second character array of the two-dimensional character array and memory is allocated for the new body character array.
}/* process message accepts a two-dimensional character array of the form [length][body] containing the message to be processed */
}return(SUCCESS);return(FAIL);This example creates a situation where the length of the body character array can be very large and will consume excessive memory, exhausting system resources. This can be avoided by restricting the length of the second character array with a maximum length check
Also, consider changing the type from 'int' to 'unsigned int', so that you are always guaranteed that the number is positive. This might not be possible if the protocol specifically requires allowing negative values, or if you cannot control the return value from getMessageLength(), but it could simplify the check to ensure the input is positive, and eliminate other errors such as signed-to-unsigned conversion errors (CWE-195) that may occur elsewhere in the code.
if ((length > 0) && (length < MAX_LENGTH)) {...}In the following example, a server object creates a server socket and accepts client connections to the socket. For every client connection to the socket a separate thread object is generated using the ClientSocketThread class that handles request made by the client through the socket.
}
} catch (IOException ex) {...}serverSocket.close();t.start();In this example there is no limit to the number of client connections and client threads that are created. Allowing an unlimited number of client connections and threads could potentially overwhelm the system and system resources.
The server should limit the number of client connections and the client threads that are created. This can be easily done by creating a thread pool object that limits the number of threads that are generated.
}
} catch (IOException ex) {...}serverSocket.close();pool.execute(t);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.
ExploitPedia is constantly evolving. Sign up to receive a notification when we release additional functionality.
If you'd like to report a bug or have any suggestions for improvements then please do get in touch with us using this form. We will get back to you as soon as we can.