Foundations of Security Week1 Lecture

Confidentiality#

• Confidentiality is the ability not to disclose information to unauthorized persons, programs, or processes.
• Confidentiality requires measures to ensure that only authorized persons have access to information
• Unauthorized persons are denied access to them
• Simply put, confidentiality means that something is secret and should not be passed on to unintentional persons or organizations.

Integrity#

• Integrity is the ability to ensure that a system and its data has not suffered unauthorized modification
• Data cannot be modified by unauthorized person while it stored in the system or transmitted through the public channel.
• Integrity protection protects not only data, but also operating systems, applications and hardware from being altered by unauthorized individuals.

Availability#

• In order for an information system to be useful it must be available to authorized users.
• Availability guarantees that users can timely and uninterruptedly accessed to the system and applications when they need them.
• The most common attack that impacts availability is denial-of-service (DoS) in which the attacker interrupts access to information, system, devices or other network resources.
• In a DoS attack, hackers flood a server with superfluous requests, overwhelming the server and degrading service for legitimate users.

Example!!!

• When Facebook went offline globally for almost 6 hours in the early hours of October 5, 2021.
• The cost of this outage, according to cybersecurity watchdog Net- Blocks, was to the tune of $160 million to the global economy.
• Facebook’s share price tumbled, and data suggests that Mark Zucker- berg, founder and CEO of Facebook, lost as much as $7 billion and Facebook saw$40 billion in market capitalization wiped out.

Brief Questions#

Snooping#

• Snooping refers to unauthorized access to or interception of data.
• For example, a file transferred through the Internet may contain confidential information.
• An unauthorized entity may intercept the transmission and use the contents for her own benefit.
• To prevent snooping, we can use encipherment (encryption).  techniques.

Attacks Threatening Confidentiality Continue…

Traffic Analysis#

• Although encryption of data may make it non-intelligible (which can not understand) for the interceptor (Attacker).
• The attacker can obtain some other type of information by monitoring online traffic.
• For example, the attacker can find the electronic address (such as the e-mail address) of the sender or the receiver.
• The attacker can collect pairs of requests and responses to help his/her guess the nature of transaction. Traffic Analysis

Attacks Threatening Integrity The integrity of data can be threatened by several kinds of attacks: modification, masquerading, replaying, and repudiation.

Modification#

• After intercepting or accessing information, the attacker modifies the information to make it beneficial to him/herself
• For example, a customer sends a message to a bank to do some transaction.
• The attacker intercepts the message and changes the type of transaction to benefit him/herself.
• Note that sometimes the attacker simply deletes or delays the message to harm the system or to benefit from it. Message Modification Attacks

Attacks Threatening Integrity Continue…

Masquerading#

• Masquerading, or spoofing, happens when the attacker impersonates somebody else.
• For example, an attacker might steal the bank card and PIN of a bank customer and pretend that she is that customer.
• Sometimes the attacker pretends instead to be the receiver entity.
• For example, a user tries to contact a bank, but another site pretends that it is the bank and obtains some information from the user. Masquerading Attacks

Attacks Threatening Integrity Continue…

Replaying#

• Replaying attack, the attacker obtains a copy of a message sent by a user and later tries to replay it.
• For example, a person sends a request to her bank to ask for payment to the attacker, who has done a job for her.
• The attacker intercepts the message and sends it again to receive another payment from the bank. Replay Attacks

Attacks Threatening Integrity Continue…

Repudiation#

• This type of attack is performed by one of the two parties in the communication: the sender or the receiver.
• The sender of the message might later deny that she has sent the message; the receiver of the message might later deny that he has received the message.
• An example of denial by the sender would be a bank customer asking her bank to send some money to a third party but later denying that she has made such a request.
• An example of denial by the receiver could occur when a person buys a product from a manufacturer and pays for it electronically, but the manufacturer later denies having received the payment and asks to be paid. Not Me

Attacks Threatening Availability

Denial of Service#

• Denial of service (DoS) is a very common attack. It may slow down or totally interrupt the service of a system.
• The attacker can use several strategies to achieve this. She might send so many bogus requests to a server that the server crashes because of the heavy load.
• The attacker might intercept and delete a server’s response to a client, making the client to believe that the server is not responding.
• The attacker may also intercept requests from the clients, causing the clients to send requests many times and overload the system. Denial of Service Attacks

Passive and Active Attacks#

• Passive Attacks: In a passive attack, the attacker’s goal is just to obtain information. This means that the attack does not modify data or harm the system.
• Active Attacks: An active attack may change the data or harm the system. Attacks that threaten the integrity and availability are active attacks. Active attacks are normally easier to detect than to prevent, because an attacker can launch them in a variety of ways.

Categorization of passive and active attacks

Fine for boy who hacked into Pentagon In 22 March 1997, a British teenager who got a D grade in A- level computer science was fined yesterday for hacking into United States defence and missile systems and removing files on artificial intelligence and battle management ²

Some British celebrities are defending him, saying he never posed a threat.

Brief Questions#

Data Integrity#

• Data integrity is designed to protect data from modification, insertion, deletion, and replaying by an adversary.
• It may protect the whole message or part of the message.

Authentication#

• This service provides the authentication of the party at the other end of the line.
• In connection-oriented communication, it provides authentication of the sender or receiver during the connection establishment (peer entity authentication).
• In connectionless communication, it authenticates the source of the data (data origin authentication).

Nonrepudiation#

• Nonrepudiation service protects against repudiation by either the sender or the receiver of the data.
• In nonrepudiation with proof of the origin, the receiver of the data can later prove the identity of the sender if denied.
• In nonrepudiation with proof of delivery, the sender of data can later prove that data were delivered to the intended recipient.

Access Control#

• Access control provides protection against unauthorized access to data.
• The term access in this definition is very broad and can involve reading, writing, modifying, executing programs, and so on.

Brief Questions#

Brief Questions#