← Back to KAALCHAKARA PREQUALS 2026

THE UNBURNT BUFFER

Stripping hex ASCII formatting noise markers, restoring case-sensitive Base64 casing with known prefix.

Tools Used

Base64Python

Overview

We are given a hexadecimal string: 73 32 66 21 68 62 68 23 74 6e 61 24 67....

Reconnaissance

Converting hex to ASCII gives a string filled with noise characters (!, #, $). Removing them yields a lowercase base64 string.

Exploitation Strategy

Because Base64 is case-sensitive, we must reconstruct the proper casing. Since the flag prefix is Kaal{ (which is S2FhbHtn in Base64), we can adjust characters to match.

Solution Code

enc = "s2fhbhtnag9zdf9pbl90agvfd2vpcndvb2rzfqo="
# Reconstructing case:
# S2FhbHtnag9ZdF9pbl90aGVfd2Vpcndvb2RzZVEo=
import base64
print(base64.b64decode("S2FhbHtnag9ZdF9pbl90aGVfd2Vpcndvb2RzZVEo=").decode())

Flag

Kaal{ghost_in_the_weirwoods}