How to Start Firewall Attack Projects Using NS2

To create a firewall attack project in NS2 (Network Simulator 2) have been includes the replicate of environment in which an attacker efforts for bypass, overcome or exploit the vulnerabilities in a firewall network. Firewall model for block the unauthorized access and this attack for challenge the firewall’s rules and mechanisms.

Here’s how you can start a firewall attack simulation project in NS2:

Steps to Simulate Firewall Attack in NS2

  1. Understand Firewall Attacks

In general firewall attack approaches has include:

  • Rule Bypass: Misusing the misconfigured rules for assign the unauthorized access.
  • Flooding: Overpower the firewall by excessive packets such as DoS/DDoS.
  • Fragmentation Attacks: Transfer the fragmented packets for bypass the inspection.
  • Spoofing: Creating the packets by fake source addresses for bypass rules.
  1. Set Up NS2
  1. Install NS2:

sudo apt-get install ns2

  1. Verify with a sample script:

ns example.tcl

  1. Define Network Topology

The topology should include:

  • Firewall node: Node has replicated the network firewall.
  • Attacker node: Replicate the attacker node has malicious traffic.
  • Legitimate nodes: Signify the general transmission for the network.
  • Victim node: It considers the goal of attack.
  1. Simulate the Firewall

We can replicate the firewall functionality in NS2 using custom logic:

  • Generate a filtering mechanism according to packet headers.
  • Stop or assign the packets terms on IP, port, or protocol.

Example TCL script for a basic firewall:

proc firewall {src dst packet} {

set src_ip [$src get-ip]

set dst_ip [$dst get-ip]

set allowed_ip “192.168.1.1”

 

# Allow only packets from allowed_ip

if {$src_ip != $allowed_ip} {

drop $packet

}

}

  1. Simulate Firewall Attacks
  2. Rule Bypass Attack
  1. Forwarding the packets by spoofed IP addresses for bypass rules.
  2. Sample for TCL script:

set attacker [$ns node]

set victim [$ns node]

set udp_attack [new Agent/UDP]

$ns attach-agent $attacker $udp_attack

set null [new Agent/Null]

$ns attach-agent $victim $null

$ns connect $udp_attack $null

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 512

$cbr set interval_ 0.01

$cbr attach-agent $udp_attack

# Simulate spoofed traffic

$ns at 1.0 “$cbr start”

  1. Firewall Flooding Attack
  1. Overload the firewall by high-frequency packets.
  2. Sample TCL script:

set udp_flood [new Application/Traffic/CBR]

$udp_flood set packetSize_ 512

$udp_flood set interval_ 0.001  # High-frequency packets

$udp_flood attach-agent $udp_attack

$ns at 1.0 “$udp_flood start”

$ns at 5.0 “$udp_flood stop”

  1. Fragmentation Attack
  1. Forwarding the fragmented packets for bypass firewall inspection.
  2. Sample:

$udp_attack set packetSize_ 200  # Small fragmented packets

  1. Trace File Analysis
  • Generate and analyze trace files (firewall_attack.tr):

awk ‘/drop/’ firewall_attack.tr > dropped_packets.log

  • Analyze metrics:
    • Packets allowed: Packets are assigned the passing through legitimate congestion.
    • Packets dropped: Malicious congestion is blocked during the packets are stopped.
    • Throughput: Performance of firewall for below the attack.
  1. Visualize Results

Use tools like Gnuplot for envision they are:

  • Numbers of packets are stopped through the firewall.
  • During the attack for degradation of throughput.

Example Gnuplot command:

set title “Firewall Performance”

plot “dropped_packets.log” using 1:2 with lines title “Dropped Packets”

  1. Simulate Defense Mechanisms

Encompass the project through executing defenses:

  • Rate Limiting: Drop packets are exceeding the certain rate.
  • Deep Packet Inspection (DPI): Examine the packet payloads for malicious designs.
  • Anomaly Detection: Identify and block the unusual congestion design.

Example rate-limiting TCL:

proc rate_limit {packet_count threshold} {

if {$packet_count > $threshold} {

drop_packet

}

}

  1. Advanced Customization

Alter the NS2’s core code (C++) for advanced environment:

  • Modify the packet behavior in the recv() method.
  • Sample in firewall.cc:

void FirewallNode::recv(Packet* p) {

hdr_ip* iph = hdr_ip::access(p);

if (iph->src() != allowed_ip) {

drop(p);

} else {

forward(p);

}

}

Example Complete TCL Script

# Initialize Simulator

set ns [new Simulator]

set tracefile [open firewall_attack.tr w]

$ns trace-all $tracefile

# Define nodes

set attacker [$ns node]

set victim [$ns node]

set firewall [$ns node]

# Create links

$ns duplex-link $attacker $firewall 1Mb 10ms DropTail

$ns duplex-link $firewall $victim 1Mb 10ms DropTail

# Attach UDP agent for attack traffic

set udp_attack [new Agent/UDP]

$ns attach-agent $attacker $udp_attack

set null [new Agent/Null]

$ns attach-agent $victim $null

$ns connect $udp_attack $null

# Firewall rule

proc firewall {src dst packet} {

set allowed_ip “192.168.1.1”

if {[$src get-ip] != $allowed_ip} {

drop $packet

}

}

# Simulate attack

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 512

$cbr set interval_ 0.001

$cbr attach-agent $udp_attack

$ns at 2.0 “$cbr start”

$ns at 5.0 “$cbr stop”

# End simulation

$ns at 6.0 “finish”

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

$ns run

Tools and Resources

  • Wireshark: Examine the network congestion created through NS2.
  • Gnuplot: Envision for the effect of attacks and defenses.
  • NS2 Documentation: Suggest for alter the NS2 modules.

In this process, we had covered the details about firewall attack implementation procedures and how to evaluate the firewall attack outcomes across the ns2 tool. If clarification is needed, it will be included in an additional project manual.