CompTIA CSA+ Study Guide. Mike Chapple
that the network in Figure 1.7 also contains a DMZ with a server called the jump box. The purpose of this server is to act as a secure transition point between the corporate network and the datacenter network, providing a trusted path between the two zones. System administrators who need to access the datacenter network should not connect their laptops directly to the datacenter network but should instead initiate an administrative connection to the jump box, using secure shell (SSH), the Remote Desktop Protocol (RDP), or a similar secure remote administration protocol. After successfully authenticating to the jump box, they may then connect from the jump box to the datacenter network, providing some isolation between their own systems and the datacenter network. Connections to the jump box should be carefully controlled and protected with strong multifactor authentication technology.
Jump boxes may also be used to serve as a layer of insulation against systems that may only be partially trusted. For example, if you have contractors who bring equipment owned by their employer onto your network or employees bringing personally-owned devices, you might use a jump box to prevent those systems from directly connecting to your company’s systems.
Cybersecurity professionals may wish to go beyond typical security controls and engage in active defensive measures that actually lure attackers to specific targets and seek to monitor their activity in a carefully controlled environment.
Honeypots are systems designed to appear to attackers as lucrative targets due to the services they run, vulnerabilities they contain, or sensitive information that they appear to host. The reality is that honeypots are designed by cybersecurity experts to falsely appear vulnerable and fool malicious individuals into attempting an attack against them. When an attacker tries to compromise a honeypot, the honeypot simulates a successful attack and then monitors the attacker’s activity to learn more about his or her intentions. Honeypots may also be used to feed network blacklists, blocking all inbound activity from any IP address that attacks the honeypot.
DNS sinkholes feed false information to malicious software that works its way onto the enterprise network. When a compromised system attempts to obtain information from a DNS server about its command-and-control server, the DNS server detects the suspicious request and, instead of responding with the correct answer, responds with the IP address of a sinkhole system designed to detect and remediate the botnet-infected system.
Secure Endpoint Management
Laptop and desktop computers, tablets, smartphones, and other endpoint devices are a constant source of security threats on a network. These systems interact directly with end users and require careful configuration management to ensure that they remain secure and do not serve as the entry point for a security vulnerability on enterprise networks. Fortunately, by taking some simple security precautions, technology professionals can secure these devices against most attacks.
Operating systems are extremely complex pieces of software designed to perform thousands of different functions. The large code bases that make up modern operating systems are a frequent source of vulnerabilities, as evidenced by the frequent security patches issued by operating system vendors.
One of the most important ways that system administrators can protect endpoints is by hardening their configurations, making them as attack-resistant as possible. This includes disabling any unnecessary services or ports on the endpoints to reduce their susceptibility to attack, ensuring that secure configuration settings exist on devices and centrally controlling device security settings.
System administrators must maintain current security patch levels on all operating systems and applications under their care. Once the vendor releases a security patch, attackers are likely already aware of a vulnerability and may immediately begin preying on susceptible systems. The longer an organization waits to apply security patches, the more likely it becomes that they will fall victim to an attack. That said, enterprises should always test patches prior to deploying them on production systems and networks.
Fortunately, patch management software makes it easy to centrally distribute and monitor the patch level of systems throughout the enterprise. For example, Microsoft’s System Center Configuration Manager (SCCM) allows administrators to quickly view the patch status of enterprise systems and remediate any systems with missing patches.
In some cases, security professionals may not be able to implement all of the desired security controls due to technical, operational, or financial reasons. For example, an organization may not be able to upgrade the operating system on retail point-of-sale terminals due to an incompatibility with the point-of-sale software. In these cases, security professionals should seek out compensating controls designed to provide a similar level of security using alternate means. In the point-of-sale example, administrators might place the point-of-sale terminals on a segmented, isolated network and use intrusion prevention systems to monitor network traffic for any attempt to exploit an unpatched vulnerability and block it from reaching the vulnerable host. This meets the same objective of protecting the point-of-sale terminal from compromise and serves as a compensating control.
Group Policies provide administrators with an efficient way to manage security and other system configuration settings across a large number of devices. Microsoft’s Group Policy Object (GPO) mechanism allows administrators to define groups of security settings once and then apply those settings to either all systems in the enterprise or a group of systems based upon role.
For example, Figure 1.8 shows a GPO designed to enforce Windows Firewall settings on sensitive workstations. This GPO is configured to require the use of Windows Firewall and block all inbound connections.
Figure 1.8 Group Policy Objects (GPOs) may be used to apply settings to many different systems at the same time.
Administrators may use GPOs to control a wide variety of Windows settings and create different policies that apply to different classes of system.
Endpoint systems should also run specialized security software designed to enforce the organization’s security objectives. At a minimum, this should include antivirus software designed to scan the system for signs of malicious software that might jeopardize the security of the endpoint. Administrators may also choose to install host firewall software that serves as a basic firewall for that individual system, complementing network-based firewall controls or host intrusion prevention systems (HIPSs) that block suspicious network activity. Endpoint security software should report its status to a centralized management system that allows security administrators to monitor the entire enterprise from a single location.
Mandatory Access Controls
In highly secure environments, administrators may opt to implement a mandatory access control (MAC) approach to security. In a MAC system, administrators set all security permissions, and end users cannot modify those permissions. This stands in contrast to the discretionary access control (DAC) model found in most modern operating systems where the owner of a file or resource controls the permissions on that resource and can delegate them at his or her discretion.
MAC systems are very unwieldy and, therefore, are rarely used outside of very sensitive government and military applications. Security Enhanced Linux (SE Linux), an operating system developed by the U.S. National Security Agency, is an example of a system that enforces mandatory access controls.
In addition to bearing responsibility for the design and implementation of security controls, cybersecurity analysts are responsible for monitoring the ongoing effectiveness of those controls. Penetration testing is one of the techniques they use to fulfill this obligation.