Passive Attacks

Have “passive attacks” which attempt to learn or make use of information from the system but does not affect system resources.

passive attacks

By eavesdropping on, or monitoring of, transmissions to:

+ obtain message contents (as shown above in Stallings Figure 1.3a), or

+ monitor traffic flows

Are difficult to detect because they do not involve any alteration of the data.

• Passive attacks are in the nature of eavesdropping on, or monitoring of, transmissions. The goal of the opponent is to obtain information that is being transmitted. Two types of passive attacks are release of message contents and traffic analysis.
• Passive attacks are very difficult to detect because they do not involve any alteration of the data. Typically, the message traffic is sent and received in an apparently normal fashion and neither the sender nor receiver is aware that a third party has read the messages or observed the traffic pattern. However, it is feasible to prevent the success of these attacks, usually by means of encryption. Thus, the emphasis in dealing with passive attacks is on prevention rather than detection.