SANS Holiday Hack Challenge 2019
Security research, CTF writeups, and hacking adventures
KringleCon 2 - Obj 7
7) Get Access To The Steam Tunnels
Difficulty: ššš (3/5) Gain access to the steam tunnels. Who took the turtle doves? Please tell us their first and last name. For hints on achieving this objective, please visit Mintyās dorm room and talk with Minty Candy Cane. In our way to the dorm to talk to Minty Candy we found a little inconvenienceā¦
Tangle Coalbox Hey kid, itās me, Tangle Coalbox. Iām sleuthing again, and I could use your help. Ya see, this here number lockās been popped by someone. I think I know who, but itād sure be great if you could open this up for me. Iāve got a few clues for you.
- One digit is repeated once.
- The code is a prime number.
- You can probably tell by looking at the keypad which buttons are used.
We are presented with the Key Lock, and we can clearly see that the code consist of 3 numbers, 1,3 and 7 because they are the mostly used on the pad. First we need a list of all permutations with repetitions of the 3 numbers in combinations of 4 We use this codeĀ we foundĀ for that to get all these 81 possible combinations: 1111,1113,1117,1131,1133,1137,1171,1173,1177,1311,1313,1317,1331,1333,1337,1371,1373,1377,1711,1713,1717,1731,1733,1737,1771,1773,1777,3111,3113,3117,3131,3133,3137,3171,3173,3177,3311,3313,3317,3331,3333,3337,3371,3373,3377,3711,3713,3717,3731,3733,3737,3771,3773,3777,7111,7113,7117,7131,7133,7137,7171,7173,7177,7311,7313,7317,7331,7333,7337,7371,7373,7377,7711,7713,7717,7731,7733,7737,7771,7773,7777, but not all match prerequisite 1 Now we need to know which one is a prime number. We need a quick code to do this for us fast We found 15 numbers and remove those that doesnāt match the conditions: 1117, 1171, 1373, 1733, 1777, 3137, 3313, 3331, 3371 3373, 3733, 7177,Ā 7331, 7333, 7717 Using the Browserās developers console on the https://keypad.elfu.org/Ā website and trying to entering some values we find the URL to use in a script instead of trying each manually
Finally, a bash for loop to a curl gives us the answer
Ā ~$ for code in 1373 1733 3137 3371 7331; do echo $i; curl āhttps://keypad.elfu.org/checkpass.php?i=$code&resourceId=undefinedā; echo -e; done
1373
{āsuccessā:false,āmessageā:āInvalidĀ Code!ā}
1733
{āsuccessā:false,āmessageā:āInvalidĀ Code!ā}
3137
{āsuccessā:false,āmessageā:āInvalidĀ Code!ā}
3371
{āsuccessā:false,āmessageā:āInvalidĀ Code!ā}
7331
{āsuccessā:true,āresourceIdā:āundefinedā,āhashā:ā677ec7081212bd3d29ec906a77f20760fb33c9c89f6955438ebbe3f10202610dā,āmessageā:āValidĀ Code!ā}
Tangle Coalbox:
Yep, thatās it. Thanks for the assist, gumshoe.
Hey, if you think you can help with another problem, Prof. Banas could use a hand too.
Head west to the other side of the quad into Hermey Hall and find him in the Laboratory.
Weāve already solved Prof Banas problem on Obj 6 Splunk⦠we continue into the dorm to look for Minty Candy.
Minty Candycane Hi! Iām Minty Candycane! I just LOVE this old game! I found it on a 5 1/4ā floppy in the attic. You should give it a go! If you get stuck at all, check out this yearās talks. One is about web application penetration testing. Good luck, and donāt get dysentery!
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