CVE-2010-0819 - Improper Input Validation

Severity

72%

Complexity

39%

Confidentiality

165%

Unspecified vulnerability in the Windows OpenType Compact Font Format (CFF) driver in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista SP1 and SP2, Server 2008 SP2 and R2, and Windows 7 allows local users to execute arbitrary code via unknown vectors related to improper validation when copying data from user mode to kernel mode, aka "OpenType CFF Font Driver Memory Corruption Vulnerability."

Unspecified vulnerability in the Windows OpenType Compact Font Format (CFF) driver in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista SP1 and SP2, Server 2008 SP2 and R2, and Windows 7 allows local users to execute arbitrary code via unknown vectors related to improper validation when copying data from user mode to kernel mode, aka "OpenType CFF Font Driver Memory Corruption Vulnerability."

CVSS 2.0 Base Score 7.2. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (AV:L/AC:L/Au:N/C:C/I:C/A:C).

Demo Examples

Improper Input Validation

CWE-20

This example demonstrates a shopping interaction in which the user is free to specify the quantity of items to be purchased and a total is calculated.


               
...

The user has no control over the price variable, however the code does not prevent a negative value from being specified for quantity. If an attacker were to provide a negative value, then the user would have their account credited instead of debited.

Improper Input Validation

CWE-20

This example asks the user for a height and width of an m X n game board with a maximum dimension of 100 squares.


               
.../* board dimensions */
die("No integer passed: Die evil hacker!\n");
die("No integer passed: Die evil hacker!\n");
die("Value too large: Die evil hacker!\n");

While this code checks to make sure the user cannot specify large, positive integers and consume too much memory, it does not check for negative values supplied by the user. As a result, an attacker can perform a resource consumption (CWE-400) attack against this program by specifying two, large negative values that will not overflow, resulting in a very large memory allocation (CWE-789) and possibly a system crash. Alternatively, an attacker can provide very large negative values which will cause an integer overflow (CWE-190) and unexpected behavior will follow depending on how the values are treated in the remainder of the program.

Improper Input Validation

CWE-20

The following example shows a PHP application in which the programmer attempts to display a user's birthday and homepage.


               
echo "Birthday: $birthday<br>Homepage: <a href=$homepage>click here</a>"

The programmer intended for $birthday to be in a date format and $homepage to be a valid URL. However, since the values are derived from an HTTP request, if an attacker can trick a victim into clicking a crafted URL with <script> tags providing the values for birthday and / or homepage, then the script will run on the client's browser when the web server echoes the content. Notice that even if the programmer were to defend the $birthday variable by restricting input to integers and dashes, it would still be possible for an attacker to provide a string of the form:


               
2009-01-09--

If this data were used in a SQL statement, it would treat the remainder of the statement as a comment. The comment could disable other security-related logic in the statement. In this case, encoding combined with input validation would be a more useful protection mechanism.

Furthermore, an XSS (CWE-79) attack or SQL injection (CWE-89) are just a few of the potential consequences when input validation is not used. Depending on the context of the code, CRLF Injection (CWE-93), Argument Injection (CWE-88), or Command Injection (CWE-77) may also be possible.

Improper Input Validation

CWE-20

This function attempts to extract a pair of numbers from a user-supplied string.


               
}
die("Did not specify integer value. Die evil hacker!\n");
/* proceed assuming n and m are initialized correctly */

This code attempts to extract two integer values out of a formatted, user-supplied input. However, if an attacker were to provide an input of the form:


               
123:

then only the m variable will be initialized. Subsequent use of n may result in the use of an uninitialized variable (CWE-457).

Improper Input Validation

CWE-20

The following example takes a user-supplied value to allocate an array of objects and then operates on the array.


               
}
list[0] = new Widget();
die("Negative value supplied for list size, die evil hacker!");

This example attempts to build a list from a user-specified value, and even checks to ensure a non-negative value is supplied. If, however, a 0 value is provided, the code will build an array of size 0 and then try to store a new Widget in the first location, causing an exception to be thrown.

Improper Input Validation

CWE-20

This application has registered to handle a URL when sent an intent:


               
}......
}
}
int length = URL.length();
...

The application assumes the URL will always be included in the intent. When the URL is not present, the call to getStringExtra() will return null, thus causing a null pointer exception when length() is called.

Overview

First reported 14 years ago

2010-06-08 20:30:00

Last updated 6 years ago

2018-10-30 16:27:00

Affected Software

Microsoft Windows 2000 Service Pack 4

Microsoft Windows XP Service Pack 2

Microsoft Windows XP Service Pack 3

Microsoft Windows XP Service Pack 2 x64 (64-bit)

Microsoft Windows 2003 Server Service Pack 2

Microsoft Windows 2003 Server Service Pack 2 Itanium

Microsoft Windows 2003 Server Service Pack 2 x64 (64-bit)

Microsoft Windows Vista Service Pack 1 (initial release)

Microsoft Windows Vista Service Pack 1 x64 (64-bit)

Microsoft Windows Vista Service Pack 2

Microsoft Windows Vista Service Pack 2 x64 (64-bit)

Microsoft Windows Server 2008 Itanium

Windows Server 2008 for 32-bit Systems

Microsoft Windows Server 2008 x64 (64-bit) (intial release)

Windows Server 2008 Service Pack 2 for 32-bit systems

Microsoft Windows Server 2008 Service Pack 2 x64 (64-bit)

Microsoft Windows Server 2008 Service Pack 2 for Itanium-Based Systems

Microsoft Windows 7

Windows Server 2008 R2 for Itanium-based Systems

r2

Windows Server 2008 R2 for 32-bit Systems

r2

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