> For the complete documentation index, see [llms.txt](https://alham-rizvi.gitbook.io/alhamrizvi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alham-rizvi.gitbook.io/alhamrizvi/picoctf-writeups/picoctf/forensics/pcap/ph4nt0m_1ntrud3r.md).

# Ph4nt0m\_1ntrud3r

so, we gort a pcap file to anlyze, i used tshark 

used -x to hex 

we got alot of base64 shit written over here, instead of wasting time decoding it and fixing the pieces of flag, i used claude AI,

<img src="https://github.com/user-attachments/assets/85bf027d-a989-4011-8357-e4e48f3b0ed9" alt="image" height="617" width="1115">

it made this py script with answers :)

import base64

## Base64 payloads extracted from each packet (offset 0x28 onward)

fragments = \[ "bnRfdGg0dA==", # nt\_th4t "YmhfNHJfMw==", # bh\_4r\_3 "XzM0c3lfdA==", # \_34sy\_t "ezF0X3c0cw==", # {1t\_w4s "NmY0YTY2Ng==", # 6f4a626 "cGljb0NURg==", # picoCTF ← likely start ]

## All b64 strings in order

all\_b64 = \[ "bnRfdGg0dA==", "Ws69hc8=", "OI/peKw=", "c66Fl+Q=", "yLAM8QQ=", "+//ymak=", "fQ==", "YmhfNHJfMw==", "azccG1s=", "AEiWtog=", "27o71z0=", "NmY0YTY2Ng==", "XzM0c3lfdA==", "1iV+7kU=", "ueV/w8g=", "ukLr5Uo=", "ezF0X3c0cw==", "YbT9C1Q=", "M2VYidA=", "cGljb0NURg==", "PadOvC4=", "NZLB/Zw=", ]

print("=== All decoded payloads ===") readable = \[] for i, b64 in enumerate(all\_b64): decoded = base64.b64decode(b64) try: text = decoded.decode('ascii') readable.append((i, b64, text)) print(f"\[{i+1:02d}] {b64:20s} → '{text}' ✓ ASCII") except: print(f"\[{i+1:02d}] {b64:20s} → (binary) {decoded.hex()}")

print("\n=== Readable ASCII fragments in order ===") flag = "" for i, b64, text in readable: flag += text print(f" Packet {i+1}: '{text}'")

print(f"\n=== Assembled flag ===\n{flag}")

```

Running this mentally, the ASCII-readable ones are:

| Packet | Base64 | Decoded |
|--------|--------|---------|
| 1 | `bnRfdGg0dA==` | `nt_th4t` |
| 8 | `YmhfNHJfMw==` | `bh_4r_3` |
| 12 | `NmY0YTY2Ng==` | `6f4a626` |
| 13 | `XzM0c3lfdA==` | `_34sy_t` |
| 17 | `ezF0X3c0cw==` | `{1t_w4s` |
| 20 | `cGljb0NURg==` | `picoCTF` |
| 7 | `fQ==` | `}` |

Reordering by flag structure (`picoCTF{...}`):
```

picoCTF{1t\_w4snt\_th4t\_34sy\_tbh\_6f4a6266.}

here is the link : <https://claude.ai/share/dce4a3f2-48e7-443a-b661-0daf55e91495>


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