Uncaught Exception

Description

When an exception is not caught, it may cause the program to crash or expose sensitive information.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following example attempts to resolve a hostname.

protected void doPost (HttpServletRequest req, HttpServletResponse res) throws IOException {
  String ip = req.getRemoteAddr();
  InetAddress addr = InetAddress.getByName(ip);
  ...
  out.println("hello " + addr.getHostName());
}

A DNS lookup failure will cause the Servlet to throw an exception.

Example Two

The _alloca() function allocates memory on the stack. If an allocation request is too large for the available stack space, _alloca() throws an exception. If the exception is not caught, the program will crash, potentially enabling a denial of service attack. _alloca() has been deprecated as of Microsoft Visual Studio 2005(R). It has been replaced with the more secure _alloca_s().

Example Three

EnterCriticalSection() can raise an exception, potentially causing the program to crash. Under operating systems prior to Windows 2000, the EnterCriticalSection() function can raise an exception in low memory situations. If the exception is not caught, the program will crash, potentially enabling a denial of service attack.

See Also