Log Hunt

Description: Our server seems to be leaking pieces of a secret flag in its logs. The parts are scattered and sometimes repeated. Can you reconstruct the original flag?

🔎 Solution

We are given a log file, and upon opening it, the very first line reveals the beginning of the flag:

[1990-08-09 10:00:10] INFO FLAGPART: picoCTF{us3_

The remaining lines mostly contain regular log information. To extract the full flag, I searched specifically for lines containing the keyword INFO FLAGPART.

> cat server.log | grep "INFO FLAGPART"
[1990-08-09 10:00:10] INFO FLAGPART: picoCTF{us3_
[1990-08-09 10:02:55] INFO FLAGPART: y0urlinux_
[1990-08-09 10:05:54] INFO FLAGPART: sk1lls_
[1990-08-09 10:05:55] INFO FLAGPART: sk1lls_
[1990-08-09 10:10:54] INFO FLAGPART: cedfa5fb}
[1990-08-09 10:10:58] INFO FLAGPART: cedfa5fb}
[1990-08-09 10:11:06] INFO FLAGPART: cedfa5fb}
[1990-08-09 11:04:27] INFO FLAGPART: picoCTF{us3_
[1990-08-09 11:04:29] INFO FLAGPART: picoCTF{us3_
[1990-08-09 11:04:37] INFO FLAGPART: picoCTF{us3_
[1990-08-09 11:09:16] INFO FLAGPART: y0urlinux_
[1990-08-09 11:09:19] INFO FLAGPART: y0urlinux_
[1990-08-09 11:12:40] INFO FLAGPART: sk1lls_
[1990-08-09 11:12:45] INFO FLAGPART: sk1lls_
[1990-08-09 11:16:58] INFO FLAGPART: cedfa5fb}
[1990-08-09 11:16:59] INFO FLAGPART: cedfa5fb}
[1990-08-09 11:17:00] INFO FLAGPART: cedfa5fb}
[1990-08-09 12:19:23] INFO FLAGPART: picoCTF{us3_
[1990-08-09 12:19:29] INFO FLAGPART: picoCTF{us3_
[1990-08-09 12:19:32] INFO FLAGPART: picoCTF{us3_
[1990-08-09 12:23:43] INFO FLAGPART: y0urlinux_
[1990-08-09 12:23:45] INFO FLAGPART: y0urlinux_
[1990-08-09 12:23:53] INFO FLAGPART: y0urlinux_
[1990-08-09 12:25:32] INFO FLAGPART: sk1lls_
[1990-08-09 12:28:45] INFO FLAGPART: cedfa5fb}
[1990-08-09 12:28:49] INFO FLAGPART: cedfa5fb}
[1990-08-09 12:28:52] INFO FLAGPART: cedfa5fb}

After collecting the matching lines, I noticed that some entries were repeated. By removing duplicates and arranging the parts in order, I was able to reconstruct the complete flag string.

🚩Flag

picoCTF{us3_y0urlinux_sk1lls_cedfa5fb}

🔎 Solution​

🚩Flag​

🔎 Solution

🚩Flag