picoCTF General Skills Guide

repetitions

Name: repetitions
Description: Can you make sense of this file? Download the file here.
Author: Theoneste Byagutangaza
Tags: Easy, General Skills, picoCTF 2023, base64
Challenge from: picoCTF 2023
Files: enc_flag
Hints:
1. Multiple decoding is always good.

Theory

According to the description, to get the flag we have to decode the text file they gave us, and I'm gonna go out on a limb and say it's the flag encoded in Base64 various times. This is because of the Base64 tag on the challenge info, and the title of the challenge being repetitions. So yeah, not much more to see in the challenge. If it really is Base64, I'm going to use an online decoder, not any fancy commands.

Solution

So this is what we get from the file:

VmpGU1EyRXlUWGxTYmxKVVYwZFNWbGxyV21GV1JteDBUbFpPYWxKdFVsaFpWVlUxWVZaS1ZWWnVh
RmRXZWtab1dWWmtSMk5yTlZWWApiVVpUVm10d1VWZFdVa2RpYlZaWFZtNVdVZ3BpU0VKeldWUkNk
MlZXVlhoWGJYQk9VbFJXU0ZkcVRuTldaM0JZVWpGS2VWWkdaSGRXCk1sWnpWV3hhVm1KRk5XOVVW
VkpEVGxaYVdFMVhSbFZrTTBKeldWaHdRMDB4V2tWU2JFNVdDbUpXV2tkVU1WcFhWVzFHZEdWRlZs
aGkKYlRrelZERldUMkpzUWxWTlJYTkxDZz09Cg==

Now we will decode this many times until we get the flag, let's go:

VmpGU1EyRXlUWGxTYmxKVVYwZFNWbGxyV21GV1JteDBUbFpPYWxKdFVsaFpWVlUxWVZaS1ZWWnVh
RmRXZWtab1dWWmtSMk5yTlZWWApiVVpUVm10d1VWZFdVa2RpYlZaWFZtNVdVZ3BpU0VKeldWUkNk
MlZXVlhoWGJYQk9VbFJXU0ZkcVRuTldaM0JZVWpGS2VWWkdaSGRXCk1sWnpWV3hhVm1KRk5XOVVW
VkpEVGxaYVdFMVhSbFZrTTBKeldWaHdRMDB4V2tWU2JFNVdDbUpXV2tkVU1WcFhWVzFHZEdWRlZs
aGkKYlRrelZERldUMkpzUWxWTlJYTkxDZz09Cg==

VjFSQ2EyTXlSblJUV0dSVllrWmFWRmx0TlZOalJtUlhZVVU1YVZKVVZuaFdWekZoWVZkR2NrNVVX
bUZTVmtwUVdWUkdibVZXVm5WUgpiSEJzWVRCd2VWVXhXbXBOUlRWSFdqTnNWZ3BYUjFKeVZGZHdW
MlZzVWxaVmJFNW9UVVJDTlZaWE1XRlVkM0JzWVhwQ00xWkVSbE5WCmJWWkdUMVpXVW1GdGVFVlhi
bTkzVDFWT2JsQlVNRXNLCg==

V1RCa2MyRnRTWGRVYkZaVFltNVNjRmRXYUU5aVJUVnhWVzFhYVdGck5UWmFSVkpQWVRGbmVWVnVR
bHBsYTBweVUxWmpNRTVHWjNsVgpXR1JyVFdwV2VsUlZVbE5oTURCNVZXMWFUd3BsYXpCM1ZERlNV
bVZGT1ZWUmFteEVXbm93T1VOblBUMEsK

WTBkc2FtSXdUbFZTYm5ScFdWaE9iRTVxVW1aaWFrNTZaRVJPYTFneVVuQlpla0pyU1ZjME5GZ3lV
WGRrTWpWelRVUlNhMDB5VW1aTwplazB3VDFSUmVFOVVRamxEWnowOUNnPT0K

Y0dsamIwTlVSbnRpWVhObE5qUmZiak56ZEROa1gyUnBZekJrSVc0NFgyUXdkMjVzTURSa00yUmZO
ek0wT1RReE9UQjlDZz09Cg==

cGljb0NURntiYXNlNjRfbjNzdDNkX2RpYzBkIW44X2Qwd25sMDRkM2RfNzM0OTQxOTB9Cg==

picoCTF{base64_n3st3d_dic0d!n8_d0wnl04d3d_73494190}

There we go! That's the flag.

I rated this level as "good"! :3