SealedRune - Reversing Challenge Writeup
This writeup details the solution to the "SealedRune" reversing challenge, focusing on the initial steps and the provided Python script output.
1. Introduction
The challenge presents a 64-bit Linux executable named challenge. The goal is to find the "incantation" required to unlock the secret and obtain the flag.
2. Initial Analysis with strings
The first step in analyzing the executable was to use the strings command to look for human-readable text and potential clues:
strings challenge
Among the output, we identified the following significant strings:
The rune glows with power... The path to The Dragon\ns Heart is revealed!- This message indicated a potential success state of the program.LmB9ZDNsNDN2M3JfYzFnNG1fM251cntCVEhgIHNpIGxsZXBzIHRlcmNlcyBlaHQ=- This string's format strongly suggested it was base64 encoded.
3. Python Decoding Script
To decode the potential base64 string, a Python script named decode.py was created with the following content:
Python
import base64
encoded_flag = "LmB9ZDNsNDN2M3JfYzFnNG1fM251cntCVEhgIHNpIGxsZXBzIHRlcmNlcyBlaHQ="
decoded_bytes = base64.b64decode(encoded_flag)
decoded_string = decoded_bytes.decode('utf-8')
reversed_flag = decoded_string[::-1]
print(f"Decoded and reversed flag: The secret spell is `{reversed_flag}`.")
This script performs the following actions:
- Imports the
base64library for decoding. - Defines the base64 encoded string.
- Decodes the base64 string into bytes.
- Decodes the bytes into a UTF-8 string.
- Reverses the decoded string.
- Prints the final result in a specific format.
4. Script Output
Executing the decode.py script yielded the following output:
└─$ python3 decode.py
Decoded and reversed flag: The secret spell is `HTB{run3_m4g1c_r3v34l3d}`.
5. Conclusion
The output of the decode.py script directly provides the flag for the challenge. The script decoded a base64 encoded string and then reversed it to reveal the secret incantation's reward.
The flag is: HTB{run3_m4g1c_r3v34l3d}