Security Attacks In Network Security

Security Attacks

Security Attacks an attack is an action that comprises the information or network security.

  • There are two types of attacks:
  1.  Passive Attack
  2.  Active Attack

Passive Attack:

The attacker only monitors the traffic attacking the confidentiality of the data. It contains release of message contents and traffic analysis (in case of encrypted data).

  • There are two types of attacks:
  1. Release of message contents
  2. Traffic Analysis

1.Release of message contents

  • The release of message contents is easily understood.
  • A telephone conversation, an electronic mail message, and a transferred file may contain sensitive or confidential information.
  • We would like to prevent an opponent from learning the contents of these transmissions.

2.Traffic analysis

  • The second type of passive attack, traffic analysis.
  • Suppose that we had a way of masking the contents of messages or other information.
  • Even if they captured the message, could not extract the information from the message. o The common technique for masking contents is encryption.
  • If we had encryption protection in place, an opponent might still be able to observe the pattern of these messages.
  • The opponent could determine the location and identity of communicating hosts and could observe the frequency and length of messages being exchanged.
  • This information might be useful in guessing the nature of the communication that was taking place.
  • 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 the sender nor receiver is aware that a third party has read the messages or observed the traffic pattern.

Active attack

  • An attacker tries to after transmitted data
  • There are two types of attacks:
  1. Masquerade
  2. Modification of Message
  3. Replay Attack
  4. Denial of Service.


1. Masquerade

  •  A masquerade takes place when one entity pretends to be a different entity (Image ). A masquerade attack usually includes one of the other forms of active attack.
  • A masquerade takes place when an attacker pretends to be an authentic user. It is generally done to gain access to a system, or steal important data from system.
  • It is generally done by stealing login id and password of authentic user to gain access to a secure network.
  • Once attacker gain access, they get full access to the network for deletion or changing of data or network policies of an organization as shown in image.

2.Replay Attack

  •  Replay involves the passive capture of a data unit and its subsequent retransmission to produce an unauthorized effect.
  • Replay Attack is also known as Playback attack where attacker repeatedly keeps on transmitting valid data again to make the network jam or delay the transmission of Data.

3.Modification of messages

  • Modification of messages simply means that some portion of a legitimate message is altered, or that messages are delayed or reordered, to produce an unauthorized effect (Image).
  • For example, a message meaning ‘Allow John Smith to read confidential file accounts” is modified to mean “Allow Fred Brown to read confidential file accounts.”

4. Denial of service

  • The denial of service prevents or inhibits the normal use or management of communications facilities.
  • This attack may have a specific target; for example, an entity may suppress all messages directed to a particular destination (e.g., the security audit service).
  • Another form of service denial is the disruption of an entire network, either by disabling the network or by overloading it with messages so as to degrade performance.

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