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cyber defense — learn
tutorials · lab 02 · networking and packet analysis
02 / 10 · INFO
01step · watch first

Read a network recording like a story.

A quick primer on opening a network recording (a "pcap") with a tool called tshark — the same moves you'll use to find the attacker's address and the door the break-in used. Watch it through, then jump to the simulation to see the messages flowing.

Lesson · Networking and Packet Analysis ~6 min
Summary what to remember
  • 1A pcap is a recording. A saved copy of every message that crossed the network — what was sent, which way it went, and exactly when.
  • 2Zoom in on one conversation. Most messages are noise. Pick out the one that matters with tcp.stream eq N (N is the conversation's number).
  • 3Read the whole conversation back. tshark -qz follow,tcp,ascii,4 glues both sides together into one readable chat.
  • 4Spot a remote-control session. A connection that stays open a long time, where one side does most of the talking, with plain text like /bin/bash -i (a command that hands over control).
  • 5The flag is the fingerprint. The attacker's address plus the door — e.g. 10.0.0.42:4444 — the one fact you hand to the security team.
beginner 200 xp ~30 min track · INFO
? Quick check · before you continue 1 question · pick one

QYou're handed one network recording and asked to find the attacker's address and the door the break-in used. Which command replays a whole single conversation back as readable text?