Exam (elaborations)
CySA+ _ Security Architecture (1)
CySA+ _ Security Architecture (1)
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CySA+ : Security ArchitectureNetwork Segmentation - ANS--determining which bits of the network are accessible to other bits
-highly secure network or single host computer may have to be physically separated from any
other network
-also referred to as system isolation or as an air gap
-Air gapping creates many management issues, done rarely
Network Segmentation (Zones and Access Control Lists (ACL)) - ANS--main unit of a logically
segmented network is a zone
-zone is area of a netowrk where security config. is the same for all hosts within it
-Network traffic between zones is strictly controlled, using a security device - typically a firewall
-firewall enforces an ACL that records IP addresses and ports that are allowed/ denied access
to the segment
Network Segmentation (Demilitarized Zones (DMZ)) - ANS--distinction between different
security zones is whether a host is Internet facing, accepts inbound connections from the
internet
-Internet facing hosts are placed in a DMZ aka perimeter network
-traffic should not be able to pass through it directly
-everything behind the DMZ is invisible to outside network
-includes web servers, mail servers, proxy servers, remote access servers
-should not be configured w/ services running on a local network i.e. authentication services
-aka bastion hosts
Network Segmentation (Jump Box) - ANS--administration server in the DMZ
-only runs the necessary admin port and protocol, typically SSH
-admins can connect to the box and then connect from there to admin interface on app server
-app server would have a single entry in its ACL, the jump box, and deny all other connections
-can be a separate server or VM
-must be tightly locked down w/ no software other than what is required to access admin
channel
Blackholes - ANS--attacker will often look for what the network is not using, unused network
ports or IP space
-these resources should be made unusable by directing them to a black hole (unable to reach
other parts of the network)
-DDoS/ flooding attacks can be directed to blackholes
Sinkhole - ANS--route traffic to an area of the network to be analyzed
-ID source of attack and filter it w/ rules
,-may be used to attract malicious traffic to honeypot/net for analysis to analyze attack and trace
their source
System Hardening - ANS--securing a PC, operating system, or application
-usually be a fairly standard series of steps to follow to configure it to perform securely in a
specific role
System Hardening (Attack Surface) - ANS--a system should run only the protocols and services
required by legitimate users and no more to reduce attack surface
-Interfaces = connection to network, if any are not required, they should be explicitly disable
-Services = provide a library of functions for different apps, should be disabled if unused
-Application service ports = allow client software to connect to application, should be disabled if
unused
-Any service or interface enabled through default installation and unconfigured is a vulnerability
Host Software Base Lining - ANS--a system in the minimum working configuration that is also
secure
-if a device deviates from the baseline, this should be investigated
Host Software Baselining Security Checklist - ANS--remove devices that have no authorized
function
-install OS and app patches/ drivers/ firmware updates
-uninstall all but necessary network protocols
-uninstall/ disable unused services
-remove/ secure any shared folders
-enforce ACLs on all files/ folders/ printers
-restrict user accounts to least privilege
-secure local admin/ root by renaming + strong pw
-disable default user/ group accounts i.e. guest
-verify permissions of system accounts/ groups i.e. removing "everyone" group from folders ACL
-install AV software and configure to update regularly
System Hardening (Compensating Controls) - ANS--mitigates for the lack of or failure of other
controls
-i.e. isolating an unpatchable system from the network or data and system backups
Group Policy Objects (GPO) - ANS--means of applying security settings (as well as other
administrative settings) across a range of computers
-configure software deployment, windows settings, custom registry settings
-can be configured on a per computer basis
Policy Security Templates - ANS--windows ships with default templates to simplify configuration
-can be modified w/ GP editor or GP management console
, Discretionary Access Control (DAC) - ANS--stresses the importance of the owner
-owner is originally the creator of the resource, though ownership can be assigned to another
user
-owner is granted full control over the resource, meaning that he can modify its ACL
-easiest model to compromise by insider threats
Mandatory Access Control (MAC) - ANS--based on the idea of security clearance levels
-each object is granted a clearance level or label
-subjects are generally allowed to access their clearance level and below
-alternatively, users can only access resources on a "need to know" basis by
compartmentalizing in groups
Endpoint Security - ANS--security procedures and technologies designed to restrict network
access at a device level
-does not replace perimeter security (DMZ/ firewalls_ but adds defense in depth
Physical Port Security - ANS--access to the physical switch ports and switch hardware should
be restricted to authorized staff,
-use a secure server room and / or lockable hardware cabinets
MAC filtering - ANS--specifying which MAC addresses are allowed to connect to a particular
port
-switches tend to operate as a hub (failopen) when the cache table becomes overloaded
Port-based Network Access Control (PNAC) - ANS--means that the switch (or router) performs
some sort of authentication of the attached device before activating the port
-device requesting access is the supplicant
-switch/ router is authenticator, enables extensible authentication protocol over LAN (EAPoL)
and waits for authentication data
-authenticator passes data to an authenticating server (typically RADIUS protocol) where it is
checked and access is granted/ denied
Network Access Control (NAC) - ANS--allows administrators to devise policies or profiles
describing a minimum security configuration that devices must meet to be granted network
access, aka health policy
-typical policies check for malware, firware/ OS patch level, personal firewall status, up to date
AV definitions, may also scan registry and perform file signature verification
NAC Features - ANS--Gather data = install and agent or poll the device
-Remediation = non-compliant devices may be refused connection or quarantined
-Management = defining policies/ reporting/ logging
-Post Admission Control = device must continue to meet policy to maintain access
-Integration = integrate w/ other client software like AV and IDS
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