IPTables Firewall Implementation

Firewall Security - Module III

• Intro IPTables
  • Discuss key IPTables concepts
  • OSI Model discussion
  • Determine if IPTables support is available in the current kernel
  • Identify key IPTables modules and supporting files
  • Explore and examine the default tables
  • Learn IPTables Access Control List (ACL) syntax
  • Discuss ACL management
  • Learn to Save & Restore IPTables ACLs
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• IPTables - Chain Management
  • Explore the various chains in the default tables
  • Discuss the purpose of each chain
  • Examine packet counts & bytes traversing the various chains
  • Focus on appending and inserting new ACLs into pre-defined chains
  • Write rules to permit common traffic flows
  • Delete & Replace ACLs to alter security policy
  • Flush ACLs - reset the security policy to defaults
  • Zero packet counts & bytes - bandwidth usage monitoring
  • Create user-defined chains to perform additional packet handling
  • Rename chains to suit the security policy/nomenclature
  • Discuss & explore chain policy
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• IPTables - Packet Matching & Handling
  • Explain the the basics of packet matching
  • Identify key layer-3/4 match objects - (Source/Dest IPs, Source/Dest Ports, etc.)
  • Explore the multi-homed configuration
  • Block traffic based on untrusted (Internet-facing) interface
  • Perform packet matching/handling based on common TCP streams
  • Perform packet matching/handling based on common UDP datagrams
  • Perform packet matching/handling based on common ICMP traffic
  • Write fewer rules (ACLs) by specifying lists of interesting layer-4 ports
  • Discuss layer-3/4 IPTables default packet matching
  • Discuss default layer-2 behavior
  • Increase security by writing rules to match packets based on layer-2 addresses
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• IPTables - State Maintenance - Stateful Firewall
  • Discuss the capabilities of traditional packet-filtering firewalls
  • Explain the advantages of stateful firewalls
  • Examine the supported connection states
  • Identify key kernel modules to support the stateful firewall
  • Implement stateful ACLs & examine traffic flows
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• IPTables - Targets - Match Handling
  • Discuss the purpose of IPTables targets for packet handling
  • Write rules with the ACCEPT target
  • Write rules with the DROP target
  • Write rules with the REJECT target
  • Write rules with the REDIRECT target
  • Confirm expected behavior for all targets
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• IPTables - Logging
  • Explore Syslog kernel logging configuration
  • Define Access Control Entry (ACEs) to perform logging
  • Explain the key fields captured by IPTables
  • Log using user-defined chain for enhanced packet handling
  • Log traffic based on security policy
  • Define a catch-all ACE
  • Use ACE negation to control logged packets
  • Label log entries for enhanced parsing
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• IPTables - Packet Routing
  • Describe subnet layout
  • Enable IP routing in the kernel - committ changes to disk
  • Update routing tables on the other Linux Hosts on the network
  • Update the Cisco PIX Firewall's routing tables
  • Test routing through the Linux router, from a remote Windows 2003 Host
  • Focus on the forward chain
  • Write ACEs to permit routing
  • Test connectivity
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• IPTables - Network Address Translation (NAT)
  • Discuss NAT features & concepts
  • Discuss & implement IP masquerading
  • Define Source NAT (SNAT) ACEs & test translations
  • Create SNAT multiples
  • Implement Destination NAT (DNAT) ACEs & test translations
  • Define DNAT multiples
  • Create NETMAP subnet mappings - one-to-one NATs
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• IPTables - Demilitarized Zone (DMZ) Configuration
  • Describe DMZ configuration
  • Write Port Address Translation (PAT) rules to permit inbound traffic
  • Test connectivity from connected subnets
  • Configure DMZ forwarding (Routing)
  • Implement Dual-DMZs - ideal for n-tiered web applications
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• IPTables - IPv6
  • Explore IPv6 configuration
  • Peruse IPv6 IPTables management tools
  • Log and Filter ICMPv6 traffic
  • Log and Filter TCPv6 traffic
  • Log and Filter UDPv6 traffic
  • Use 'nping' to generate IPv6 traffic for analysis
  • Create IPv6 Sub-Chains to manage rules
  • Evaluate results
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Sums

• Various Tools
• Remote Confirmations
• File Metadata
• File Fragments
• Compress Content
• Archive Content
• DIR Hierarchy
• Password Sums
• Shared Secret
• Restrict History
• Downloaded Content
• Encrypt Content
• Site Credentials
• Site COOKIE
• Site COOKIE - Unique

CentOS9x Stream Administration

• Initial Environment
• ls, pwd, cd, cp, mv, rm, mkdir, rmdir, whoami
• alias, cat, file, chmod, chown, history
• STD(IN|OUT), Pipes, Redirection, Command Chaining
• ps, df, top, free
• Pagers, W-Commands
• Checksums
• Awk | Sed | Grep Usage
• BASH SHELL Environment
• Compression | Archival Tools
• SSH Equivalence
• SHELL Quoting
• Propagate Environment
• Secure Clients

• Identify Standard File Types
• Standard File Permissions
• Symbolic Links
• Transfer Permissions

• Identify SWAP environment
• Provision dedicated SWAP partitions
• Add | Remove SWAP from pool as needed
• Provision File System-based SWAP
• SWAP Share
• SWAP Persistence
• Identify default storage configuration
• Provision new storage as needed
• XFS - File System
• XFS - Grow File System
• Identify LVM defaults
• Add new partitions to LVM management
• Allocate storage to LVM Volume Groups
• Create Logical Volumes (LVs) as needed
• Overlay File System and mount where applicables
• LVM - Resize
• LVM - Mixed FS
• LVM - SWAP

• Features
• Install
• Defaults
• General Usage
• Update Accounts

• Defaults
• Shared PASS Gen
• Unique PASS Gen
• Encrypted PASS Gen
• Update Accounts
• Groups

• Discuss features | limitations
• Identify default system-wide schedule
• Peruse various default Cron Jobs
• Schedule simple job and monitor recurrence
• Evaluate results

• Peruse Default CONF
• Discuss Syslog Rules
• Explore Log Rotate defaults
• Ensure rotated logs are compressed
• Extend default retention scheme
• Force Log Rotation as needed

• Explore Default environment
• Install PKGs
• Dump important metadata from packages
• Apply Updates

• Default CONF
• Add | Confirm IPs as needed

• Install
• Copy Configuration
• SELinux - Confirm
• TLS | SSL Services
• cURL Client Tests
• Virtual Hosts
• ENC Sites Only

• SFTP Only USER
• SFTP Only USER - NOLOGIN
• SFTP Only Group - Control
• NMap Intro

SysLOG with rSysLogD

• Discuss Features
• Default Environment
• Kernel Firewall LOG
• Split LOGs by Priorities
• UDP | TCP Logging
• Dual L4 Logging
• Multiple Hosts
• Basic Queueing
• Reliable Event Logging Protocol (RELP)
• RELP - Remote Only
• RELP Only
• Traditional to RELP
• SysLOG Clear-Text - Confirm
• Property Filters
• Expression Filters
• Relay Chain

Netfilter Tables

• Features
• SSHGuard
• Ruleset Basics
• Persistence
• Sample Rules
• Inbound Filtering
• Dormant Table
• Manage Tables | Chains | Rules
• Counters
• Sets
• LOG Basics
• LOG with Sets
• Closed-Port LOGs
• LOG Options
• Re-Route LOGs
• Jump Targets
• Chain Jumping
• GoTo Chains
• Meta Selectors

Debian 12x Administration

• Features
• Download
• Graphical Install
• Text Install
• Post-Install Tweaks

• Explore usage of the following useful commands
• tty | /dev/pts | w | whoami | who
• set | env | export | unset
• cat | echo | touch | rm
• pwd | ls | cd | mkdir | alias | umask
• head | tail
• dd
• find
• history
• STDIN, STDOUT, STDERR, UNIX Pipes, Redirection, Command Chaining
• ps, df, free, top, dd
• stat, which, w, who
• tar | gzip | bzip2 | xz
• ZSH Setup

• Network Tools | IP Configuration
• Examine default IP configuration
• Extend IP configuration to facilitate additional addresses
• Static IP Config
• Dual: Dynamic | Static Config
• Multiple Interfaces
• Dual Network Services
• Confirm communications

PHP One-Liners

• General Usage
• Count Lines
• Word Count
• Count Chars
• Split Lines into ARRAY
• Count Instances of Fields
• Transform Delimiters
• Anonymize LOGs
• Extract Unique SRCs
• Lines by Error Code
• LOG By Code
• Summarize Error Codes
• Pre-Seed Error Codes
• Random Strings
• Varied Passwords
• Expose Undefined Passwords
• Outdated Passwords
• Hash | Un-Hash

Cloud Storage with GlusterFS

• Discuss Features:
• Default Volume Type
• Common Volume Types
• Transport Types
• File System Support
• Storage Model

• Features
• Provision Storage
• Allocate GlusterFS Brick
• Persistence
• Generate IO
• Multiple File Systems
• Various Sizes
• Stop | Remove Volume
• Reconstitute Volume
• Server Mount
• Evaluate

OpenPGP with GPG

• Discuss Features:
• Primary Tool
• Private | Public Keys
• Public Key Cryptography Standards (PKCS)
• Encryption | Decryption
• Signing | Verification

• Features
• General Usage
• Create Content
• Encrypt
• PassPhrase Protect
• Binary | Text Encryption
• Share
• Decrypt

SSL-TLS with OpenSSL

• Discuss Features:
• Primary Tool
• Private | Public Keys
• Certificate Signing Requests (CSRs)
• Self-Signed Certificates
• Public Key Cryptography Standards (PKCS)
• Encryption | Decryption
• Random String Generation
• Message Digests
• SSL-TLS Client

• Features
• General Usage
• Retrieve Site Certificates
• Determine OCSP Configuration
• Probe supported TLS Versions
• Extract Certificate for local usage
• Retrieve Certificate with NMap
• Retrieve Certificate Chain

• Discuss
• Generate Private Keys
• Generate Correlating CSRs
• Confirm Keys | CSRs
• Self-Signed Certificates

SSH Variables

• Discuss Features
• Bare VARs
• SSH Client
• Double Quotes
• Single Quotes
• SSH Environment

SHELL Variables

• Discuss Features
• Terminal (TTY)
• CLI Arguments
• Process ID
• Backgrounded
• SHELL Local
• Environment
• Persistence
• Aliases
• Command Substitution
• Increment | Decrement
• Dynamism