Computer Networks and Information Security

Separating duties prevents any single individual from gaining complete control over critical processes. This security control distributes authority and responsibility, reducing the risk of fraud, errors, or unauthorized actions.

An unattended session occurs when an authenticated user physically leaves their workstation or connection without properly terminating. This security risk exposes active sessions to potential unauthorized access by nearby individuals.

The user who initiated the session remains accountable for all activities occurring during that session. This principle establishes clear security responsibility, ensuring users protect their credentials and properly terminate sessions.

When a buffer receives more data than its capacity, the excess data overflows into adjacent memory locations, overwriting whatever valid data was stored there. This is called a buffer overflow vulnerability. Options A and B are incorrect because networks don't 'bounce back' or 'absorb' excess data in this way. Option D is wrong because compilers don't remove excess data at runtime.

A flooding attack is a type of DoS attack where a target is overwhelmed with more traffic or packets than it can process. This exhausts the target's resources, making it unavailable to legitimate users. The other terms (saturating, inundation, data-surge) are not standard terminology for DoS attack types.

IP spoofing is an attack where hackers forge the source IP address in packets to disguise their identity or impersonate a trusted system. This allows attackers to bypass basic IP-based authentication and launch attacks while hiding their true location. Back-door, birthday attacks, and man-in-the-middle are different types of attacks with distinct mechanisms.

A backdoor attack involves a deliberate hidden access point in software that allows unauthorized entry, bypassing normal authentication. This could be intentionally left by developers or maliciously inserted. Birthday attacks involve hash collisions, man-in-the-middle intercepts communications, and spoofing forges identities - none match the deliberate code opening scenario.

Social engineering attacks manipulate human psychology, so end user education is the primary defense against them in organizations. While firewalls and technical controls help, they cannot prevent users from being manipulated. Inbox rules and corporate intranets are technical tools that don't address the human vulnerability that social engineering exploits.

Striping in RAID distributes data across multiple disks, allowing simultaneous read/write operations which significantly improves performance. Parity provides redundancy, mirroring creates identical copies for fault tolerance, and clustering combines multiple systems - none of these primarily improve performance through data distribution.

Cellular topology is particularly susceptible to security violations due to its distributed nature and use of public airwaves for transmission. The broadcast-based communication and reliance on multiple base stations create numerous potential entry points for attackers. Linear, star, and ring topologies have more centralized control and typically wired connections which are easier to secure.

A one-time password (OTP) is valid only for a single login session and then discarded, providing strong security against replay attacks. Dynamic passwords may change but aren't necessarily single-use, static passwords don't change, and hybrid passwords aren't a standard authentication category.

Throughput rates measure how fast a biometric system can process verification attempts, and larger biometric data files take longer to process, reducing throughput. Data collection techniques, enrollment time, and user contact are not directly affected by file size in the same way.

Biometric authentication falls into 'what we are' (something inherent to the person) as opposed to 'what we know' (passwords), 'what we have' (tokens/smart cards), or 'what we use' (not a standard authentication category). Retinal patterns are unique biological characteristics intrinsic to each individual.

CHAP (Challenge Handshake Authentication Protocol) uses a one-way hash value to authenticate without sending the actual password across the link, protecting against eavesdropping. Plaintext passwords would be insecure, digital signatures are for non-repudiation, and asymmetric encryption is not CHAP's mechanism.

Parity RAID's main benefit is data redundancy - it uses parity information to reconstruct data if a disk fails. While it can provide some performance benefits, that's not the primary purpose (striping does that). Mirroring stores multiple copies (not parity's approach), and parity RAID definitely provides value.

A Local Area Network (LAN) is confined to a small geographic area like a single building or campus. It connects devices within a limited area using private networking equipment. WANs span large geographic areas, MANs cover metropolitan regions, and WLANs are wireless LANs.

Data striping (used in RAID 0) spreads data across multiple disks to improve read/write performance by allowing simultaneous operations. It does not provide redundancy - in fact, striping alone increases risk of data loss because if one disk fails, all data is lost. Redundancy comes from mirroring or parity schemes.

Mesh topology has every node directly connected to every other node, providing maximum redundancy and reliability. Full mesh means n(n-1)/2 connections for n nodes. Linear, Ring, Star, and Tree topologies all have specific connection patterns where not all nodes connect directly to each other.

Cellular topology organizes coverage into circular (often approximated as hexagonal for efficient tiling) geographical areas called cells, with a node (base station) at the center of each cell. This is how mobile phone networks provide coverage across large areas. Ring, Star, and Mesh refer to connection patterns between devices, not geographical coverage areas.