Computer Security PDF

Computer Security What’s Ahead? Understand the basic concepts of Computer Security; Identify common threats to Computer Security; Understand the role of policy in computer security; Identify some computer security mechanisms Computer Security What does security mean? In...

Computer Security What’s Ahead? Understand the basic concepts of Computer Security; Identify common threats to Computer Security; Understand the role of policy in computer security; Identify some computer security mechanisms Computer Security What does security mean? In computer and networking, one of the most important concerns people have about computing transactions is security. Security means that no one should be able to break into my computer, attack my computer, steal my information, use my computer to attack others, damage my computer or data, use my resources without my permission, etc. Computer Security Computer vs. Network Security Computer security aims to protect a single connected machine while network security seeks to protect communication and all its participants. Computer Security Computer Security Threats a. Breaking into my computer such as those done by hackers, worms and viruses. b. Attacking my Computer Denial of service attack Viruses and some worms c. Stealing an information d. Using my computer to attack others Email Worms and viruses Denial-of-service attacks Spam phishing Computer Security Computer Security Threats e. Damaging my computer or data Impose some measure to prevent break-ins such as the use of cryptography to detect tampering, replicate data to recover from tampering. f. Taking up the resources with irrelevant messages This computer abuse is done through the Denial-of-service attacks, Spam mail which takes time to read and fills space, Malicious mail which may contain a virus and worms. Computer Security Aspects of Computer Security a. Confidentiality - Keep data secret from non-participants b. Integrity, Aka “authenticity”, keep data from being modified and keep it functioning properly c. Availability - keep the system running and reachable Computer Security Why we aren’t secure? a. Buggy code These include unvalidated input, cross-site scripting, buffer overflow, injection flaws, and improper error handling. b. Protocol design failures A security measure is implemented within the context of a protocol that specifies the appropriate procedures for data handling. Thus, poor protocol design offers many security vulnerabilities. c. Weak cryptography Cryptography is also useful for authentication, Integrity checking, and Non-repudiation. Here is a sample Crypto Scheme: Ceasar’s Cipher Substitute each letter with a letter which is three letters later in the alphabet. Thus, “HELLO” becomes “KHOOR” Computer Security Why we aren’t secure? d. Social engineering/human factor gaining access to systems or data by exploiting human psychology, rather than by breaking in or using technical hacking techniques. e. Insider threats An insider threat is known as a security threat that originates from within the organization being attacked or targeted, often an employee or officer of an organization. f. Poor configuration Networks are often reconfigured to accommodate new tasks or users, and failure to properly configure your servers, computers and network devices can lead to a wide variety of security problems. Computer Security Why we aren’t secure? g. Incorrect policy specification h. Stolen keys or identities i. Misplaced incentives (spoofing, tragedy of the commons) Spoofing is a type of scam where an intruder attempts to gain unauthorized access to a user's system or information by pretending to be the user. The primary purpose is to trick the user into releasing sensitive information to gain access to one's bank account, computer system or to steal personal information, such as passwords. Email spoofing URL spoofing Caller ID spoofing Computer Security The Role of Policy A policy defines what is allowed and how the system and security mechanisms should act. The policy is enforced by a mechanism which interprets and enforces it, e.g., Firewalls, Intrusion Detection System(IDS), Access control lists. Implemented as software (which must be implemented correctly and without vulnerabilities). Computer Security Some Security Mechanisms a. Encryption Computer Security Some Security Mechanisms b. Checksums The data is prepared for transmission Checksum (hash sum) refers to the process of performing data integrity checks. After receipt, the data is decrypted Computer Security Some Security Mechanisms c. Authentication the act of confirming the truth of an attribute of a single piece of data claimed true by an entity. d. Authorization Authorization is a security mechanism used to determine user privileges or access levels related to system resources. Authorization is usually preceded by authentication for user identity verification. During authorization, a system verifies an authenticated user's access rules and either grant or refuses resource access. Computer Security Some Security Mechanisms e. Firewalls Generally, firewalls are configured to protect against unauthenticated interactive logins from the "outside" world. A firewall helps prevent vandals from logging into machines on your network. f. VPNs g. Intrusion Detection h. Virus scanners Computer Security Today’s Security Deployment a. Firewalls, VPN’s. A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting outward communication. A VPN service acts as a tunnel to secure your internet connection on wifi and protect your data. b. Internet Protocol Security (IPSec) is a framework of open standards for ensuring private, secure communications over Internet Protocol (IP) networks, through the use of cryptographic security services. c. SSL (Secure Sockets Layer) is a standard security protocol for establishing encrypted links between a web server and a browser in online communication. The usage of SSL technology ensures that all data transmitted between the web server and browser remains encrypted. d. Virus scanners e. The intrusion detection system (IDS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Computer Security Today’s Security Deployment a. Firewalls, VPN’s. A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting outward communication. A VPN service acts as a tunnel to secure your internet connection on wifi and protect your data. b. Internet Protocol Security (IPSec) is a framework of open standards for ensuring private, secure communications over Internet Protocol (IP) networks, through the use of cryptographic security services. c. SSL (Secure Sockets Layer) is a standard security protocol for establishing encrypted links between a web server and a browser in online communication. The usage of SSL technology ensures that all data transmitted between the web server and browser remains encrypted. d. Virus scanners e. The intrusion detection system (IDS) is a device or software application that monitors a network or systems for malicious activity or policy violations.