Channel Accessible by Non-Endpoint

Description

In order to establish secure communication between two parties, it is often important to adequately verify the identity of entities at each end of the communication channel. Inadequate or inconsistent verification may result in insufficient or incorrect identification of either communicating entity. This can have negative consequences such as misplaced trust in the entity at the other end of the channel. An attacker can leverage this by interposing between the communicating entities and masquerading as the original entity. In the absence of sufficient verification of identity, such an attacker can eavesdrop and potentially modify the communication between the original entities.

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

In the Java snippet below, data is sent over an unencrypted channel to a remote server.

Socket sock;
PrintWriter out;

try {

  sock = new Socket(REMOTE_HOST, REMOTE_PORT);
  out = new PrintWriter(echoSocket.getOutputStream(), true);

  // Write data to remote host via socket output stream.
  ...

}

By eavesdropping on the communication channel or posing as the endpoint, an attacker would be able to read all of the transmitted data.

See Also