CSY450 Pervasive Computing Lecture 6 PDF

CSY450. Pervasive Computing Lecture 6: Security Issues in Pervasive Computing. Heba KH. Ahmed, Ph.D. Associate Professor, Computer Systems Department. Faculty of Computer & Information Science. Agenda 1. Security. 2. Traditional Security Issues. Integrity, Confidentiality,...

CSY450. Pervasive Computing Lecture 6: Security Issues in Pervasive Computing. Heba KH. Ahmed, Ph.D. Associate Professor, Computer Systems Department. Faculty of Computer & Information Science. Agenda 1. Security. 2. Traditional Security Issues. Integrity, Confidentiality, Nonrepudiation, and Availability. 3. Mobile and Wireless Security Issues Detectability, Limited resources, Interception, and Theft-of-service. 4. Ad Hoc Networks Security Issues 1- Security The traditional problems of security, How mobile and wireless systems introduce some additional problems and make some traditional problems more difficult 3 2- Traditional Security Issues 1. Integrity, 2. Confidentiality, 3. Nonrepudiation, and 4. Availability. 4 Traditional Security Issues 1- Integrity System integrity: A system provides integrity if it performs its intended function in an unimpaired (perfect) manner, free from deliberate or unintended unauthorized manipulation of the system. Data Integrity: Data maintains its integrity if the receiver of the data can verify that the data have not been modified; in addition, no one should be able to substitute fake data. 5 Traditional Security Issues 2- Confidentiality Confidentiality refers to data and is provided when only intended recipients can read the data. Anyone other than the intended recipients either cannot retrieve the data because of access mechanism protections, or other means, such as encryption, protect the data even if they are stolen or intercepted. 6 Traditional Security Issues 3- Nonrepudiation Nonrepudiation is a property of data and means that the sender should not be able to falsely deny (i.e., repudiate) sending the data. This property is important for electronic commerce because vendors do not want clients to be able to deny that they made purchases and thus must pay for any services or goods they received. 7 Traditional Security Issues 4- Availability Availability is a property of systems where a third party with no access should not be able to block legitimate parties from using a resource. Denial-of-service (DoS) attacks are commonplace on the Internet: They can involve one site flooding another with traffic Distributed denial-of-service sends a flood of traffic to disable a site. Unlike the DoS attack, though, the DDoS attack employs a large number (hundreds or more) of machines to participate in the attack. 8 Traditional Security Issues Availability The “syn flood” attack creates many “halfopen” Transmission Control Protocol (TCP) connections so that the target computer no longer accepts any new connections. The “smurf” attack sends an Internet Control Message Protocol (ICMP) packet to a broadcast address resulting in a large number of replies, flooding a local network. The “ping of death” attack crashes target machines by sending them ping packets larger than they can handle. The “teardrop” attack crashes machines that improperly handled fragmented TCP/IP packets with overlapping Internet protocol (IP) fragments. 9 3- Mobile and Wireless Security Issues Detectability, Limited resources, Interception, and Theft-of-service 10 Mobile and Wireless Security Issues Detectability, Nonmobile users typically do not face this problem. In some circumstances, the mobile users do not want their wireless system to be detected, and this is part of the reason they are mobile. 11 Mobile and Wireless Security Issues Resource depletion/exhaustion Depletion: involves an attack that shortens the lifespan of the battery, causing it to fail “naturally” at a later date but much sooner than it would normally. Exhaustion involves an attack that consumes (and wastes) all the power in the battery, leaving the unit unable to function. These attacks can cause key routing nodes in the network to fail, leaving parts of the network unreachable. 12  Mobile and Wireless Security Issues Physical intercept problems (Packet Sniffing) In wireless systems, the signal is broadcast through the air, where any receiver can intercept it. This problem is related to the detectability problem because once the signal can be detected, the data can be read. 13  Mobile and Wireless Security Issues Theft of service For example, a user may be sitting outside a coffee shop known to have a public wireless Internet connection. A business next door also may have a wireless network, and because of the user’s physical location, she may have better reception to the next-door business’s wireless network and connect to it, thinking that she is connecting to the coffee shop’s network. Of course, this example assumes that the user has no malicious intent, nor any knowledge of what network she is using. 14 4- Ad Hoc Networks Security Issues Ad hoc networks form on the fly, without a fixed infrastructure. Data in ad hoc networks typically pass through several other ad hoc nodes. Typically, there is no guarantee as to the identity of these intermediate nodes, so “man in the middle” attacks can be used to copy or corrupt data in transit. 16 Additional Common Attacks “Man in the middle” attacks A man in the middle attack occurs when a malicious node inserts itself in the path between two nodes. The most obvious use is to snoop on the conversation between the two nodes. In addition, the malicious node may choose to modify the data from the source before it forwards them to the recipient or simply to drop certain packets. 17  Ad Hoc Networks Security Issues Routing: There are several security risks associated with routing. spoofing, in which one node impersonates another. key routing nodes can be disabled via a resource-exhaustion attack 18 Ad Hoc Networks Security Issues Pre-keying One problem when using encryption or authentication is key management, which involves creating, sharing, storing, and revoking encryption keys. Of course, if a fixed key is used, then there is no easy way to handle compromised keys, nor to change them periodically to avoid the risk of exposure through use. For some applications, because of either network or processor limitations or application constraints, a high-cost key-exchange protocol is not practical. Public key encryption is one way to avoid needing a key exchange. 19  Additional Common Attacks Traffic analysis Even without decrypting the data, attackers can gain insight about the meaning of the data by observing properties such as message sizes, communication pairs, and the sequence of encrypted back-and-forth conversations. This technique is called traffic analysis. There are stories about pizza deliveries to the Pentagon dramatically increasing the night before military actions; 20 Additional Common Attacks Buffer-overflow attacks A buffer-overflow attack occurs when a code segment that reads input does not perform any bounds checking on the amount of input it accepts. If the input exceeds the input buffer space allocated for it, it overwrites memory adjacent to the buffer. Typically, the calling stack or data for local variables gets corrupted. 21 References Fundamentals of Mobile and Pervasive Computing - Frank Adelstein and Sandeep KS Gupta (Chapter 12,13) Creese, Sadie, Michael Goldsmith, A. W. Roscoe and Irfan Zakiuddin. “Authentication for Pervasive Computing.” SPC (2003). 22 Thank You ☺ 23