Firewall
Firewalls provide the first line of defense for networks by isolating them from each other. You can purchase standalone firewall devices or integrate them into other infrastructure devices like routers and servers. There are both hardware and software solutions for firewalls available today. Some firewalls are appliances that act as the central device between two networks. A packet-filtering network security firewall is the simplest and most basic type.
The firewall uses filters to inspect incoming and egress packets against predefined rules before allowing them. The ruleset, or access list, is usually predefined based on various metrics and can include IP addresses of source and destination IPs; port numbers at both source and destination; protocols; OSI model layers 3 & 4, where this kind of security posture filtering takes place and some commonly available filtering options; for instance:
Source IP Address for Incoming Packets -- IP packets indicate where data originates; you can manage its flow by authorizing or disallowing traffic based on its IP address. Likewise, by blocking specific botnets or unapproved websites based on IP addresses, you may be able to stop them more effectively.
Destination IP Addresses
The destination IP addresses represent where packets will arrive upon delivery to their receivers. Unicast packets, for example, are designed for one machine and contain only one destination IP address; multicast security controls (or broadcast) boxes typically reach multiple IP addresses simultaneously and cyber threats target numerous computers on a network.
To reduce the load on target computers and protect susceptible machines on internal networks from being exposed unknowingly through multicast traffic from multiple IPs simultaneously, rulesets block traffic from specific IPs, thereby protecting unwanted access by third parties or blocking individual IPs in multicast.Filtering can be done based on protocol information in each packet, which enables you to block traffic that uses a particular protocol security tools security issues.
Packet-filtering firewalls are known for their fast performance, as most of their work takes place at Layer 3 or below, eliminating the need for complex application knowledge. They're often utilized at the periphery security networks of an organization and have proven very successful against DoS attacks that target security gaps in sensitive systems within internal networks.
Packet-filtering firewalls do have some drawbacks. As they only cover OSI Layer 3 and below, packet-filtering firewalls cannot examine application-level data, and application-specific attacks can penetrate internal networks easily. Furthermore, firewall filters cannot filter Layer 3 information if an attacker falsifies IP addresses; most packet-filtering firewalls cannot detect faked IPs or ARPs, thus making these business processes firewalls best used against denial-of-service attacks.
Stateful Packet Filtering Firewall
Stateful packet-filtering techniques are highly advanced but still adhere to the basic capabilities of firewalls that use packet-filtering technology. They operate at Layer 4, and connection pairs typically have four parameters.
Stateful inspection techniques use dynamic memory to store state tables for security strategy incoming and established connections, updating state tables whenever a host attempts to connect externally. You can define rules that determine whether certain packets pass or are dropped - similar to firewalls with packet filtering capabilities, such as forbidding packets that exceed 1023 port numbers from passing. For instance, most servers only respond to standard ports security measures up through the 1023 range.
Stateful packet filtering firewalls provide excellent network protection but are less flexible and robust than regular firewalls. When adding dynamic tables to a firewall architecture, complexity increases exponentially, resulting in slower operation and decreased user network performance. Stateful packet filtering firewalls cannot access application services and higher layer protocols for inspection either.
Stateful inspections occur at all network levels to provide additional security, particularly for connectionless protocols like User Datagram Protocol or Internet Control Message Protocol. Stateful inspections offer increased protection, especially concerning connectionless protocols like User Datagram Protocol or security program Internet Control Message Protocol.
They are installed between remote users (who might be connected through public networks like the Internet) and dedicated servers, where only proxies can be seen as intermediaries between themselves and real users. Users only see these intermediary servers, while servers discover only proxy IPs - neither party knows their real user!
Application proxy firewalls' biggest drawback lies in the speed and cost considerations; their activities occur at the application level and require significant data processing power, although application proxies remain one of the safest technologies.
Web Application Firewall (WAF)
Web application firewalls offer security for web applications by setting rules in HTTP conversations. Because applications must remain online, specific ports must remain accessible to the Internet; otherwise, attackers could potentially target particular websites against either their application or database.
WAFs are typically designed to protect servers, while proxy firewalls typically safeguard clients. WAFs are especially helpful because they can detect DDoS attacks early, absorb traffic volume quickly, and identify their attacker.
Intrusion Detection System (Ids)
IDSs enhance cybersecurity by quickly detecting any intrusion and eliminating it swiftly to avoid breaches and breaches in future. They also record events to help defend against intrusions later. Having an IDS can allow businesses to respond more rapidly when an attack strikes; responding promptly saves both time and money when dealing with legal matters or repair bills for damage done to networks or hardware.
Attackers may exploit security mechanisms like firewalls and cryptography. Any such compromises must be reported immediately to administrators using an intrusion detection system; an intrusion detection system makes this easy.
Deploying an IDS allows administrators to identify vulnerabilities. It exploits that a potential attacker could exploit while classifying these intrusion detection systems according to specific categories:
Intrusion Detection Systems Based On Host-Based Hosts
Host-based intrusion detection systems (IDSs) are intended to detect, monitor and respond to attacks and activity on specific hosts. Hackers often target corporate networks with confidential data by installing scanning software and exploiting vulnerabilities to record user activity. Some host-based IDSs provide data forensics, statistical analysis and policy management at the host level - working best when an attacker attempts to gain access to files or services on the computer host; typically, these host-based IDSs are integrated into operating systems because hackers frequently target vulnerabilities within OSes when trying to gain entry.
Network-Based Intrusion Detector Systems
Network traffic-based IDSs use network traffic to detect intrusions. These systems, commonly called packet sniffers, read through incoming traffic to ascertain if a network has been compromised. Many proprietary and Internet protocols, such as TCP/IP and NetBEUI that send messages between internal and external networks are vulnerable and require extra ways of detecting malicious activities. Unfortunately, intrusion detection systems often struggle with encrypted data from virtual private networks. In contrast, network speeds of over 1Gbps require modern and expensive IDSs for optimal functioning.
Agents working together form an essential element of any distributed intrusion detection system. Agents are autonomous or semi autonomous software that runs in the background to perform valuable tasks; unlike IDSs, agents detect intrusions and send attack information back to central servers for analysis. Multiple agents operating together form networks that facilitate data processing and transmission more comprehensively than single or central IDSs could.
Intrusion Prevention System (IPS)
An intrusion prevention system (IPS), also known as intrusion detection systems and firewalls combined, is designed to detect and prevent intruders from launching attacks against networks. Intrusion Prevention Systems combine both functions. Since an IPS implementation can be costly, businesses should assess their IT security risks before making this investment decision. IPSs don't offer as robust performance as firewalls or intrusion detection systems, so it may not be appropriate if speed is critical for business operations.
Active response must be distinguished from intrusion prevention. Active response devices utilize triggers generated from packet inspection devices to dynamically reconfigure or change network access control, session streams or individual packets in response. Enthusiastic response takes place following an event.
A single packet attack might succeed on its initial attempt but will soon become unsuccessful; active response devices may prove beneficial but are ineffective solutions due to this aspect. However, Network intrusion prevention devices are inline devices that inspect packets before sending them onward. Such an IPS can protect against single packet attacks by either blocking or altering them inline; for optimal effectiveness, it must perform analysis and inspection at wire speed to detect zero-day and application layer attacks as soon as they emerge.
At the operating system layer, intrusion prevention systems exist as well. They can intercept system calls, memory accesses, processes, and other system functions to stop attacks and protect users against them. There are various intrusion prevention technologies:
System Memory and Process Protection: An intrusion prevention strategy at the system level. Memory protection prevents one process from corrupting another on the system. In contrast, process protection monitors their execution to identify and terminate attacks instantly.
Inline Network Devices: These network devices are placed directly in the path of network communications and serve to block or modify attack packets as they pass through them. Similar to routers but with IDS signature matching capabilities, these real-time detection and response capabilities enable real-time response before being sent onto their destination networks.
Session Sniping: This intrusion prevention technique uses TCP RST packets to terminate TCP connections upon an attempted attack attempt and flush any exploit from buffers, effectively stopping attacks. For maximum effectiveness, sequence and acknowledgement numbers must match on all TCP RST packets to effectively counterattack.
Gateway Interaction Devices: Gateway Interaction Devices are an intrusion-prevention strategy that enables detection devices to interact dynamically with network gateways, such as routers and firewalls, to stop attacks when detected. If detected, such detection devices instruct these network devices to stop an attack immediately.
Active Response IDS deployment presents additional identifier challenges regarding session sniping systems. An attacker could use RST packet terminations from enthusiastic response IDS systems as an avenue of attack by using passive operating system identification software that analyzes packets for operating system information; using such knowledge against IDS could evade or target it together.
Active response IPSs present another risk regarding the timing of gateway interactions and race conditions. A typical situation would see the detection device instruct a firewall or router to block an attempted attack; due to network latency; however, the attacker had already passed through before receiving instructions to stop. Similar circumstances could arise where an attack creates an open race condition on a gateway between itself and responses for defenses; both scenarios increase the chance that an attempt at attack succeeds.
Wireless Intrusion Detection And Prevention System (Widps)
Wireless Intrusion Prevention Systems (WIPS) are standalone security devices or software applications that constantly monitor a wireless LAN to detect suspicious access points and other wireless security risks.
WIDPSs compare all wireless access points connected to a network with its authorized list and notify IT staff if any are mismatched. Some high-end WIDPSes, like Cisco's, analyze radio frequency fingerprints generated by wireless devices to block MAC address spoofing; you can even use WIndows as access points to turn off signals from untrustworthy mobile APs! Besides adding another layer of security for wireless LANSes, WIDPSc are also ideal for network monitoring as they can detect configuration errors. This layer exists on OSI at the Data Link level!
Three basic deployment methods are available:
- Wireless access points serve a dual purpose: they offer network traffic wireless connectivity while periodically searching for unauthorized access points. A
- Sensors installed into authorized access points continuously scans radio frequency in search of unapproved access points.
- Sensors are placed throughout a building to monitor radiofrequency. Once collected, this data is returned to a central server for analysis, action and storage. This method may cost more due to dedicated hardware costs, but it is considered the most effective approach.
Unified Threat Management (UTM) refers to an approach in information security in which one piece of hardware or software can perform multiple functions (intrusion protection, antivirus protection, content filtering). Traditional point solutions cannot fulfill all security functions properly with UTM. UTM simplifies information security management, offering security administrators one centralized point for monitoring and reporting instead of having multiple products from various vendors. UTM appliances have quickly gained popularity due to their ease of installation, configuration and maintenance. A UTM is more cost-efficient when compared with managing multiple security systems as it provides features like:
- Network firewall
- Intrusion detection
- Intrusion prevention
- Gateway Antivirus
- Proxy firewall
- Deep packet inspection
- Filtering web content and proxy services
- Data loss prevention (DLP)
- Security Information and Event Management
- Virtual Private Network (VPN)
- Network Tarpit
Network Access Control (NAC)
NAC (Network Access Control) devices help protect network security by restricting network firewall resources to devices that adhere to your policies. Furthermore, NAC may be configured to repair non-compliant equipment to keep your network secure automatically. Network access control (NAC) can make a tremendous difference to endpoint security on a network. NAC checks whether device settings comply with security policy before granting access, such as checking for the latest antivirus or patch versions installed on hosts. NAC will permit a device to join a network if all conditions are fulfilled; otherwise, NAC may quarantine or connect it directly to a guest network if its policy has not been adhered to. NAC uses either agents or agentless evaluation technology to evaluate each device's security level.
Proxy Server
Proxy servers mediate between client software that accesses resources from other servers and those servers themselves. A proxy server receives client requests (for instance, to visit websites). It evaluates and either approves or denies them based on criteria established by its administrators. Forward proxies typically retrieve data for their clientele.
An "open proxy server" refers to any proxy server accessible by all Internet users. At the same time, its reverse counterpart (also called a surrogate) protects and regulates access to private servers within networks. Reverse proxy servers can also help balance load by providing authentication and decryption, caching and encryption functions - functions that fall under web application firewalls, as previously explained.
Transparent or nontransparent proxy can be employed. Transparent proxies do not alter requests or responses beyond what is necessary for proxy identification and authentication, meaning clients don't need to know they exist. Nontransparent proxies modify demands or reactions to provide additional services such as group annotation, media type transformations, protocol reduction or anonymity filtering for user agents.
Proxy servers are frequently utilized by organizations for web filtering and performance enhancement (load balancers) as well as traffic filtering purposes.
Web Filter
Web filters prevent users' browsers from loading certain pages on websites. URL filtering involves blocking certain websites based on their URL address, thus restricting access to specific ones and web-based applications. Content filtering systems instead block data based on its content rather than where it comes from; Microsoft implemented one as an anti-phishing measure; this was then replaced by SmartScreen Filter, which works automatically by sending websites addresses directly to its server where they're compared against a list of known phishing and malware websites before being displayed a blocking page warning users not to continue browsing such sites.
Web filter appliances come with additional technologies that block malicious websites, allowing you to build your list of sites to stop and utilize safe listing or delisting services for website blocks. Furthermore, cached pages or traffic data analysis provides valuable insight into users' interests and usage habits on the Internet - invaluable information when used for insider threat prevention.
Network Load Balancer (Nlb)
Load balancers are physical devices that direct computers towards specific servers within a network based on various factors - including how many connections a server receives or its performance. Organizations use load balancers to reduce the chances of overloading servers while optimizing bandwidth utilization among all computers on their network.
Load balancers can be implemented either as software or hardware solutions. They're typically associated with devices like routers, firewalls, network address translation appliances (NAT), etc. Load balancers divide website traffic into separate requests that are distributed among redundant servers when they become available; scheduling load balancers to divide work and distribute across servers becomes an integral aspect of load-balancing systems.
Network load balancers can be configured in either active-active, active-passive, or both modes. When configured as active-active, multiple load-balancing servers are constantly processing requests. At the same time, in an active-passive setup, there is typically only one primary server, with other listener servers ready to step in when this one becomes overwhelmed and split the load among themselves.
Spam Filter
Mail gateways can serve multiple functions beyond simply routing mail: encryption and, to an extent, DLP is also possible. Spam filters, on the other hand, typically help to detect unwanted emails and prevent them from reaching their recipient's inbox. Spam filters evaluate emails according to policies or patterns set by an organization.
In contrast, more advanced filters use heuristic analysis techniques to detect spam by looking for suspicious word patterns and word frequencies in email communications. Filtering relies on rules, such as blocking emails from specific IP addresses or with certain words in their subject lines. Spam filters are typically used for inbound messages; however, they can also be used for outgoing messages to detect PCs within your company that might have been infected with viruses.
Conclusion
At this point, we have covered most devices and software available to increase network security, from firewalls and antivirus software to physical barriers like fences. As with any new security device implementation, always conduct an IT security assessment before purchasing or installing one - this will help determine whether investing in such an investment will yield positive returns.There are four major categories of firewalls. They are packet-filtering, stateful packet filtering, proxy and web application firewalls.
