Chapter 1: Network Security Concepts and Policies

Network Security Concepts and PoliciesTo protect assets!Historically done through physical security and closed networks.Purpose of SecurityWith the advent of personal computers, LANs, and the wide-open world of the Internet, the networks of today are more open.The Network TodayTo provide adequate protection of network resources, the procedures and technologies that you deploy need to guarantee three things :ConfidentialityIntegrityAvailability of systems and dataBasic Security RequirementsAn asset is anything of value to an organization.A vulnerability is a weakness in a system or its design that could be exploited by a threat.A threat is a potential danger to information or systems.A risk is the likelihood that a particular vulnerability will be exploited.An exploit is an attack performed against a vulnerability.A countermeasure (safeguard) is the protection that mitigates the potential risk.Data, Vulnerabilities, and CountermeasuresNeed for Network SecurityBusiness goals and risk analysis drive the need for network securityDealing with Risk :ReduceLimitation/avoidanceAssuranceDetectionRecoverryNeed for Network SecurityAdversaries, Methodologies, and Classes of AttackAdversaries : To defend against attacks on information and information systems, organizations must begin to define the threat by identifying potential adversaries. These adversaries can include the following: Nations or statesTerroristsCriminalsHackersCorporate competitorsDisgruntled employeesGovernment agencies, such as the National Security Agency (NSA) and the Federal Bureau of Investigations (FBI)Adversaries, Methodologies, and Classes of AttackMethodologies :Step 1. Perform footprint analysis (reconnaissance).Step 2. Enumerate applications and operating systems.Step 3. Manipulate users to gain access.Step 4. Escalate privileges.Step 5. Gather additional passwords and secrets.Step 6. Install back doors.Step 7. Leverage the compromised system.Adversaries, Methodologies, and Classes of AttackThreats Classification• Enumeration and fingerprinting• Spoofing and impersonation• Man-in-the-middle• Overt and covert channels• Blended threats and malware• Exploitation of privilege and trust• Confidentiality• Password attacks• Availability attacks• Denial of service (DoS)• Botnet• Physical security attacks• Forces of natureIP Spoofing AttacksTCP Three-Way HandshakeSequence PredictionSequence Number PredictionTrust ExploitationTrust ExploitationConfidentiality and Integrity AttacksBreach of ConfidentialityMan-in-the-Middle AttacksIP Source Routing AttackOvert and Covert ChannelsOvert ChannelPrinciples of Secure Network DesignDefense in depthCompartmentalizationLeast privilegeWeakest linkSeparation and rotation of dutiesHierarchically trusted components and protectionMediated accessAccountability and traceabilityEvaluating and Managing the RiskRisk Analysis and ManagementEvery process of security should first address the following questions:• Which are the threats the system is facing?• Which are the probable threats and what would be their consequence, if exploited?The threat-identification process provides an organization with a list of threats to which a system is subject in a particular environment.Risk AnalysisQuantitativeQualitativeBuilding Blocks of Risk AnalysisAssets and their valueVulnerabilitiesThreats, their impact, and rate or probability of occurrenceList of Assets and Their ValueA Lifecycle Approach to Risk ManagementSecurity PoliciesThe three reasons for having a security policy are as follows:• To inform users, staff, and managers• To specify mechanisms for security• To provide a baselineA properly defined security policy does the following:• Protects people and information• Sets the rules for expected behavior• Authorizes staff to monitor, probe, and investigate• Defines the consequences of violationsSecurity Policy ComponentsComponents of a Comprehensive Security PolicySecure Network Lifecycle ManagementOrganization-wide Integration of IT Governance, Risk Management, Compliance