What you will learn
- Understand TCP/IP and common protocols
- Read packet and flow data
- Recognize suspicious network behavior
Network Security CTF Challenges
Learn TCP/IP, DNS, packet analysis, and network attack evidence through safe, reproducible exercises.
Network Security challenges
16 challenges available.
Network SecurityLevel 1★☆☆☆☆08. Network Basics - Learn Port Numbers
Networks use port numbers to identify services. For example, a web server (HTTP) usually uses port 80, and encrypted…
Network SecurityLevel 2★★☆☆☆Network Analysis - DNS Zone Transfer Leak
An unauthenticated DNS zone transfer (AXFR) against a misconfigured authoritative server was captured. Download the…
Network SecurityLevel 2★★☆☆☆Network Analysis - ICMP Data Exfiltration
Data was exfiltrated from the internal host 10.20.0.15 to the external host 203.0.113.66 disguised as ping (ICMP echo…
Network SecurityLevel 2★★☆☆☆Network Analysis - SMB Share Enumeration Leak
An attacker enumerating SMB shares on the network was captured. Download the packet capture (traffic.pcap), follow the…
Network SecurityLevel 2★★☆☆☆Network Analysis - Telnet Credentials
A legacy server was administered over Telnet in clear text. Download the packet capture (traffic.pcap), follow the…
Network SecurityLevel 2★★☆☆☆Network Analysis - Anonymous FTP Transfer
An anonymous FTP session was captured in clear text. Download the packet capture (traffic.pcap), follow the FTP data…
Network SecurityLevel 2★★☆☆☆Network Analysis - Clear-text HTTP Credentials
Analyze traffic intercepted on public Wi-Fi where someone logged in over plain HTTP. Download the packet capture…
Network SecurityLevel 2★★☆☆☆Network Analysis - Plaintext SMTP Attachment
The internal host 10.30.0.25 sent an email to port 25 of the mail server 10.30.0.10 without encryption. Download…
Network SecurityLevel 3★★★☆☆Network Analysis - 802.1Q VLAN Separated Traffic
capture.pcap was captured from a mirrored switch trunk port, so frames from several VLANs are mixed together with…
Network SecurityLevel 3★★★☆☆Network Analysis - SNMP Information Leak
A device speaking SNMPv2c with a weak community string (public) was captured returning a GetResponse. Download the…
Network SecurityLevel 3★★★☆☆Network Analysis - SSL Strip Clear-text Credentials
An SSL Strip attack downgraded HTTPS to HTTP, so the victim's credentials traveled in clear text and were captured.…
Network SecurityLevel 3★★★☆☆Network Analysis - Unmasking WebSocket Frames
capture.pcap records WebSocket traffic between a browser and a chat server. Every client-to-server frame is masked…
Network SecurityLevel 3★★★☆☆Network Analysis - Custom Protocol Decoding
Traffic from a system using a small custom binary protocol was captured. Download the packet capture (traffic.pcap),…
Network SecurityLevel 4★★★★☆Network Analysis - Rebuilding Chunked gzip HTTP from TCP
capture.pcap records two HTTP exchanges over one TCP connection. The server's segments are reordered and some are…
Network SecurityLevel 4★★★★☆Network Analysis - TCP Retransmission Covert Channel
capture.pcap contains TCP retransmissions with duplicate sequence numbers. Extract retransmissions whose payload…
Network SecurityLevel 5★★★★★Network Analysis - IPv4 Overlapping Fragment Reassembly
The UDP datagram with IPv4 ID 0xbeef in fragments.pcap contains overlapping fragments that overwrite earlier bytes.…