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Mmh Delicious

Description of the challenge​

  • CTF Name : Hackday 2026
  • Category : Forensics
  • Difficulty : Intro
  • Date : 23-25 January 2026

We are given the following challenge :

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Analyzing the PCAP file​

We open the provided PCAP file in Wireshark. We start by looking at the protocols used in the capture. We notice some packet are using the HTTP protocol among the rest of the traffic :

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We start by filtering the HTTP traffic by typing http in the filter bar. We then look at the different HTTP requests and responses. After a quick look, we notice a suspicious HTTP HEAD request :

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We can clearly see a base64 encoded string in the Cookie header. We decode it using Cyberchef :

cmVtaW5kIG1lIG15IHN1cGVyIGltcG9ydGFudCByZXVuaW9uIGFib3V0IEhBQ0tEQVl7ODN3QVIzX1QwX0AhX0FnZU5UfSBpbiB0d28gaG91cnM=
remind me my super important reunion about HACKDAY{83wAR3_T0_@!_AgeNT} in two hours
FLAG

HACKDAY{83wAR3_T0_@!_AgeNT}