Snakecode write-up ca 2022 We found this ancient text inscribed on a stone tablet. We believe it describes the history and technology of a mighty but extinct civilization, but we can’t be certain as it’s written in a dead language. Can you use your specialist knowledge to uncover the truth, and recover their technology?

The file is a pyc file which can be decompiled with uncompyle6 resulting in:

uncompyle6 version 3.7.4
Python bytecode 2.7 (62211)
Decompiled from: Python 2.7.18 (v2.7.18:8d21aa21f2, Apr 20 2020, 13:25:05) [MSC v.1500 64 bit (AMD64)]
Embedded file name: ./snake_obf.py
Compiled at: 2022-01-18 00:16:46

import marshal, types, time ll = types.FunctionType(marshal.loads(('YwEAAAABAAAABQAAAEMAAABzNAAAAHQAAGoBAHQCAGoDAHQEAGQBAIMBAGoFAHwAAGoGAGQCAIMB\nAIMBAIMBAHQHAIMAAIMCAFMoAwAAAE50BAAAAHpsaWJ0BgAAAGJhc2U2NCgIAAAAdAUAAAB0eXBl\nc3QMAAAARnVuY3Rpb25UeXBldAcAAABtYXJzaGFsdAUAAABsb2Fkc3QKAAAAX19pbXBvcnRfX3QK\nAAAAZGVjb21wcmVzc3QGAAAAZGVjb2RldAcAAABnbG9iYWxzKAEAAAB0AQAAAHMoAAAAACgAAAAA\ncwcAAAA8c3RkaW4+dAoAAABsb2FkTGFtYmRhAQAAAHQAAAAA\n').decode('base64')), globals()) i0 = ll('eJxLZoACJiB2BuJiLiBRwsCQwsjQzMgQrAES9ythA5JFiXkp+bkajCB5kKL4+Mzcgvyikvh4DZAB\nCKKYHUjYFJekZObZlXCA2DmJuUkpiXaMEKMZGAC+nBJh\n') i1 = ll('eJxLZoACJiB2BuJiLiBRwsCQwsjQzMgQrAES9ythA5LJpUXFqcUajCB5kKL4+Mzcgvyikvh4DZAB\nCKKYHUjYFJekZObZlXCA2DmJuUkpiXaMEKMZGADEORJ1\n') f0 = ll('eJxLZmRgYABhJiB2BuJiXiBRw8CQxcCQwsjQzMgQrAGS8ssEEgwaIJUl7CAiMzc1v7QEIsAMJMoz\n8zTASkBEMUiJTXFJSmaeXQkHiJ2TmJuUkmgHVg5SAQBjWRD5\n') f1 = ll('eJxLZmRgYIBhZyAu5gISNQwMWQwMzQwMwRogcT8wWcIKJNJTS5IzIFxmIFGemacBpBjARDE7kLAp\nLknJzLMr4QCxcxJzk1IS7cDKQSoAvuUPJw==\n') f2 = ll('eJx1kL1uwkAQhOfOBsxPQZUmL+DOEnWUBghEQQbFIESVglUkY5ECX+lHoMz7Jrt7HCgSOWlGO/rm\n1tbtIwBBY1b9zdYYkEFlcRqiAQoWxaginDJhjcUBijNQy+O24jxgfzsHdTxOFB8DtoqPoK7HPcXn\ngCPFZ1BfcUGsdMA/lpc/fEqeUBq21Mp0L0rv/3grX/f5aELlbryVYzbXZnub7j42K5dcxslym7vu\nJby/zubrK1pMX9apPLOTraReqe9T3SlWd9ieakfl17OTb36OpFE/CDQDE5vHv7K/FKBNmA==\n') f3 = ll('eJxVj00KAjEMhV+b8Q9040IZT9C9WxHEvRvBC1iFUhhk2sUIIwgexLWn1KQzI9qSl/DlhaZHDSDj\nII4tR3ix1IBVyK1GXitImt/0l1JDSSih1rAZfIZyI4x9BRIkeKA8SLeF1Dl9clIHG+c9OakdZ35O\nT/o+yiciZI2Hgvpt702Pt925Nx/HFZwSGbIYqaL87FS5aKSIgi5JbZR/F1WTrkZmk4QByypE64p1\nap6X4g8LaaoZ3zFGfzFVE/UBTuovhA==\n') f4 = ll('eJw1zDsKgEAMBNCJilb2drZ7AEuxsbfxBOIHFFkWNqWdF3eyYJEXkgxZcwB/jazYkkdwUeAVCAcV\nW3F4MjTt7ISZyWVUS7KEsPtN7cW9e2ddLeKTIXk7gkSsSB91O/2g9uToLBELO0otH2W6Ez8=\n') f5 = ll('eJxdjr0OwjAMhM9J+as6M7HTF0AsiKV7F54ACJUKVaiSjOnEi2MbISQGf4rtu3OuMwBSBVfDFQdG\nBhzwMAgNMsER1s58+wJ3Hlm4Ai/z33YGE+A1IrNljnBBtiLYT1ZSf2sr6lMt19u+ZPYQkGDJqA0j\nycfap7+lBT/C2bveJ/UkEQ7KqByTGMbPKNQSpojiPMTEzqNKup2aKlnShramopJW5g2ipyUM\n') f6 = ll('eJxdjTEOglAQRB98iMbEKxhLbkBjaLSwsrHWBEUJCRKULTT5VFzc3W9nMS+zk93ZqwNS1UK1VQ17\nRQ0CVcQUsTvljO4vWjEmSIRP8A4PXn3MlHKOea4DlxyzWMsOjXUHK/bpVXb1TWy855kF2gN9SPo2\nDD9+At8Zdm4YZorNIFXTFTI335aPS1UWtie28QV3xx4p\n') f7 = ll('eJxtjz8LwjAQxV/S1mrRxcnZKat/qyAuOrv0E4ilIJRS2hsUCg7OfmcvubZTIe/97nKPcHkEADpd\nWPWPjYCGj0Kj0fjIfHwVqiWIbzxbJ6SHEleQ1yf8ocQHFLSJqgKN+nTYVUUEGndNCiRG8UY3M7F7\nabb7TrAS7AVrQSw4CDaCreBo7CfJPvdy/nZeummZuyY3bHBWh2ynmtJncXaRLLaJem6HaqGiVlMV\n6Zn+Azn/L1k=\n') f8 = ll('eJwljr0KAkEMhCf3o2hrIb7BlWIhFiKC1jYWViKHe+qKnHob0GKt7sVNcsV8ZDeTSc45gJ5oINqI\nwkkQgTvQAvRdgwmO0BK2xxl+uTUTxBwugUtxT8EZIiHKZ4o21dZE7FLRe4yD+nMLixlchvG+0KU7\nPxR6EVjhSVDoKazt86MqG6uasr5WrI3SucCNbJPEp685keIy576aqktThVs3r0kf48s8r4c9Ogaj\nL3SnIej8MrDz9aqLXJhPzwMNaURT4R/aUC0X\n') a1 = ll('eJxLZmRgYIBhZyAuZgESKYwMwRpMQIZfCUhcWwNIMGiAmGB+DoQPIorZgYRNcUlKZp5dCQeInZOY\nm5SSaAdWDFIBALI0C1U=\n') a2 = ll('eJxLZmRgYIBhZyAuZgESKYwMwRpMQIZfCUhcWQNIMGiAmGB+DoQPIorZgYRNcUlKZp5dCQeInZOY\nm5SSaAdWDFIBALBMC00=\n') a3 = ll('eJw10EtLw0AUBeAzTWLqo74bML8gSyFdiotm40rEZF+kRyVtCGKmqzar/nHvHBDmfty5c+fBrB2A\niUVuUVkMG4MOnIARGIMJeAKm4BQ8Bc9UsfwcvABn/5VL8Aq81tINeAveKb/Hd47R4WDDTp5j7hEm\nR4fsoS4yu+7Vh1e8yEYu5V7WciffZCl/5UpW8l162cuF3Mq1fJSUY5uYhTZFRvfZF+EvfOCnU89X\ngdATGFLjafBs+2e1fJShY4jDomvcH1q4K9U=\n') a4 = ll('eJxLZmRgYIBhZyAuZgESKYwMwRpMQIZfCUhcRQNIMGiAmGB+DoQPIorZgYRNcUlKZp5dCQeInZOY\nm5SSaAdWDFIBALCJC04=\n') a5 = ll('eJxNzTELwjAQBeCXS4r6TzKJP6DUgruLq0s1S7BKIRkqJP/dd3Hp8D4ex3H3NAA6xjEXJo2kAHeH\nalAF1aI6FINg8BIsZxTZdM5lM2/95i2PXCNBPBCvzeubLOR4yvp2bX6bS3P+LyppR/qUQ/wMea99\nnt6PMA26l/SKxQ/XGxky\n') a6 = ll('eJwlzLsKwkAQheF/L0afw2qr4AOENOnT2NpEgyDGENgtFHbfPTNrcT6G4cw8DHCQeMkgiWchw81T\nDMVSHMWTDdnytGTHu+Ea9G4MAkHPkxXaS9L1t/qrbtXlX1TiUehiml9rn046L9PnPk+99qJ+cewN\nxxM9\n') a7 = ll('eJwlzLEKwjAQxvF/rhF9jk6Zig8gXdy7uLq0FqFYRUiGFpJ39y4O34/j+O4eDjhovOaqia2S4e4p\njiKUhuLJjiw8hex5Cbdgd0NQCHaeROnOydZbda9+q+u/aMSjcolpXj59Otm8ju9pHnvrRfvS8AMM\nqhM6\n') a8 = ll('eJxLZmRgYABhJiB2BuJiPiBRw8CQwsgglsLEkM3EEKzBDBTyy2QFkplAzKABJkCaSkBEjgZcsJgd\nSNgUl6Rk5tmVcIDYOYm5SSmJdmDFIBUAVDAM/Q==\n') a9 = ll('eJxLZmRgYIBhZyAuZgESKYwMwRpMQIZfCUhcQQNIMGiAmGB+DoQPIorZgYRNcUlKZp5dCQeInZOY\nm5SSaAdWDFIBAK+VC0o=\n') m0 = ll('eJw1jTELwjAUhC9Jq/0VzhldBAfr4u7i6mYpFFSKCXRJp/7x3rsi5L5Avnsvrx0AS8PcmNQSGSg8\nDsWjBJQKS42nxwzMQSog09b/gsrs9AGP6LjhHr3tMfSn7TpH+yebfYtJHGXH7eknTpGAkPbEJeVu\n+F5V/Bw1Wpl0B7cCYGsZOw==\n') m1 = ll('eJw1zUEKAjEMBdCfdMQreIRuRwU3Mhv3bjzCDAOCitCAm7rqxU1+cZGX0v408wbAvy5e5eQYUAUm\nqAnNHdASvsJLhSVUBpryoPG6Km5ZfPaah/hBnXXf29jbsbdDjl0W2Tdd6IN+6JwdkLJ1zsWW+2vi\n/HOMRIklkJ38AF2QGOk=\n') m2 = ll('eJxNjj8LAjEMxV96fz+Fk0NHdT5c3F1cD5c7BEHlsAWXdrov7kuKICS/0LyXpFMP4JcnZrgSEUgM\nQXJIDVKLtcHokAWZKvsVUm0eGjr1rC3GCplBW/03Xpy2hM5bj4sXnjh7p4cUz30pO6+fiKouxtn6\ny8MehcH4MU7GtydgCB0xhDjfX8ey8mAzrYqyka18AW5IIKw=\n') def snake(w): r = i0() c = i1() f0(w) d = (0, 1) p = [(5, 5)] pl = 1 s = 0 l = None while 1: p, d, pl, l, s, w, c, r = m2(p, d, pl, l, s, w, c, r) time.sleep(0.4) return i1().wrapper(snake)

The challenge is on reversing the lambda functions that follow. My first attempt was at decompiling the ll function that is used to load all the other functions. But the other functions are already compiled as well so my first plan failed. Then while testing the snake i saw that it fed me letters randomly so i decided to disassemble all the functions to see the logic of the game.

I deciphered most of it before i saw that the flag was hiding into one of the lambda functions. I tried 2 methods first didn’t work but still might work for you: method 1: from lamtest import myfunc import inspect inspect.getsource(myfunc) method 2: import dis

>>> dis.dis(a3) 2 0 LOAD_CONST 1 ('H') 3 LOAD_CONST 2 ('T') 6 LOAD_CONST 3 ('B') 9 LOAD_CONST 4 ('{') 12 LOAD_CONST 5 ('S') 15 LOAD_CONST 6 ('u') 18 LOAD_CONST 7 ('P') 21 LOAD_CONST 8 ('3') 24 LOAD_CONST 9 ('r') 27 LOAD_CONST 10 ('_') 30 LOAD_CONST 5 ('S') 33 LOAD_CONST 8 ('3') 36 LOAD_CONST 11 ('C') 39 LOAD_CONST 12 ('R') 42 LOAD_CONST 13 ('t') 45 LOAD_CONST 10 ('_') 48 LOAD_CONST 5 ('S') 51 LOAD_CONST 14 ('n') 54 LOAD_CONST 15 ('4') 57 LOAD_CONST 16 ('k') 60 LOAD_CONST 8 ('3') 63 LOAD_CONST 17 ('c') 66 LOAD_CONST 18 ('0') 69 LOAD_CONST 19 ('d') 72 LOAD_CONST 8 ('3') 75 LOAD_CONST 20 ('}') 78 BUILD_LIST 26 81 STORE_FAST 1 (f) 3 84 LOAD_FAST 1 (f) 87 LOAD_FAST 0 (pl) 90 LOAD_CONST 21 (5) 93 BINARY_DIVIDE 94 LOAD_GLOBAL 0 (len) 97 LOAD_FAST 1 (f) 100 CALL_FUNCTION 1 103 BINARY_MODULO 104 BINARY_SUBSCR 105 RETURN_VALUE