{"id":712,"date":"2022-09-04T19:07:55","date_gmt":"2022-09-04T10:07:55","guid":{"rendered":"https:\/\/emeth.jp\/diary\/?p=712"},"modified":"2022-09-04T19:13:00","modified_gmt":"2022-09-04T10:13:00","slug":"cakectf-2022-nimrev-zundamon-writeup","status":"publish","type":"post","link":"https:\/\/emeth.jp\/diary\/2022\/09\/cakectf-2022-nimrev-zundamon-writeup\/","title":{"rendered":"CakeCTF 2022 nimrev, zundamon writeup"},"content":{"rendered":"\n

\u53c2\u52a0\u3057\u30662\u554f\u89e3\u3044\u305f\u306e\u3067writeup<\/p>\n\n\n\n

\"\"<\/div>
2022.cakectf.com<\/div><\/div>
\"\"<\/figure>
CakeCTF 2022<\/div>
https:\/\/2022.cakectf.com<\/div>
2022-09-03 14:00:00 +09:00 \u2013 2022-09-04 14:00:00 +09:00<\/div><\/div>
<\/div><\/div><\/a><\/div><\/div>\n\n\n\n\n\n\n\n

nimrev<\/h2>\n\n\n\n

Nim\u8a00\u8a9e\u3067\u66f8\u304b\u308c\u305f\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30ea\u30d0\u30fc\u30b9\u30a8\u30f3\u30b8\u30cb\u30a2\u30ea\u30f3\u30b0\u3002
Nim\u306e\u5185\u90e8\u51e6\u7406\u306f\u308f\u304b\u3089\u306a\u3044\u304c\u3001\u95a2\u6570\u540d\u304b\u3089\u63a8\u6e2c\u3057\u3064\u3064call<\/code>\u3092\u8ffd\u3063\u3066\u3044\u304f\u3068\u3001NimMainModule<\/code>\u304c\u30e1\u30a4\u30f3\u51e6\u7406\u3067\u3042\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002
\u3055\u3089\u306b\u7d30\u304b\u3044\u3053\u3068\u3092\u8003\u3048\u305acall<\/code>\u3092\u8ffd\u3063\u3066\u3044\u304f\u3068\u3001<\/p>\n\n\n\n

  1. \u6a19\u6e96\u5165\u529b\u304b\u3089\u8aad\u307f\u8fbc\u3080<\/li>
  2. \u914d\u5217\u3092\u4f5c\u6210\u3057\u3066\u5024\u3092\u8a2d\u5b9a<\/li>
  3. \u914d\u5217\u3092map\u3059\u308b<\/li>
  4. \u914d\u5217\u3092join\u3059\u308b<\/li>
  5. eqStrings\u306e\u7d50\u679c\u3067\u5206\u5c90\u3057\u3066”Correct!”\u304b”Wrong!”\u306e\u3069\u3061\u3089\u304b\u3092\u51fa\u529b<\/li><\/ol>\n\n\n\n

    \u3068\u3044\u3046\u6d41\u308c\u3068\u63a8\u6e2c\u3067\u304d\u308b\u3002
    Nim\u516c\u5f0f\u306e\u30ea\u30d5\u30a1\u30ec\u30f3\u30b9<\/a>\u3092\u53c2\u7167\u3057\u3066map\u51e6\u7406\u6642\u306e\u30d7\u30ed\u30b7\u30fc\u30b8\u30e3\u306e\u5f15\u6570\u4f4d\u7f6e\u3092\u78ba\u8a8d\u3001\u30b3\u30fc\u30c9\u304b\u3089\u8a72\u5f53\u3059\u308b\u7b87\u6240\u3092\u63a2\u3059\u3068NOT<\/code>\u3057\u3066\u308b\u3060\u3051\u3068\u308f\u304b\u308b\u306e\u3067\u30012.\u306e\u914d\u5217\u306b\u8a2d\u5b9a\u3055\u308c\u305f\u5024\u306eNOT<\/code>\u3092\u53d6\u3063\u3066\u30d5\u30e9\u30b0\u3092\u53d6\u5f97\u3002<\/p>\n\n\n\n

    Flag: CakeCTF{s0m3t1m3s_n0t_C}<\/code><\/p>\n\n\n\n

    zundamon<\/h2>\n\n\n\n

    \u5b9f\u884c\u30d5\u30a1\u30a4\u30eb\u3068pcap\u3092\u6e21\u3055\u308c\u308b\u3002pcap\u306b\u306f\u8907\u6570\u306eIP\u306e\u901a\u4fe1\u304c\u3042\u308b\u306e\u3067\u3001\u307e\u305a\u306f\u3053\u306e\u5b9f\u884c\u30d5\u30a1\u30a4\u30eb\u306e\u901a\u4fe1\u5148\u3092\u78ba\u8a8d\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u3002<\/p>\n\n\n

    \n
    \"\"<\/a><\/figure>\n<\/div>\n\n\n

    sink<\/code>\u95a2\u6570\u3092\u8997\u304f\u3068\u901a\u4fe1\u56de\u308a\u306e\u521d\u671f\u51e6\u7406\u3092\u3084\u3063\u3066\u304a\u308a\u3001\u3053\u3053\u3067\u901a\u4fe1\u5148\u304c164.70.70.9:6379<\/code>\u3067\u3042\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002pcap\u304b\u3089\u8a72\u5f53\u3059\u308b\u5185\u5bb9\u3092\u78ba\u8a8d\u3059\u308b\u3068\u3053\u3093\u306a\u611f\u3058\u3002<\/p>\n\n\n

    \n
    \"\"<\/a><\/figure>\n<\/div>\n\n\n

    $17<\/code>\u306e\u5f8c\u306bMAC\u30a2\u30c9\u30ec\u30b9\u3068\u601d\u308f\u308c\u308b17\u30d0\u30a4\u30c8\u3001$3<\/code>\u306e\u5f8c\u306b3\u30d0\u30a4\u30c8\u306e\u30c7\u30fc\u30bf\u3092\u9001\u3063\u3066\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002MAC\u30a2\u30c9\u30ec\u30b9\u306f\u6700\u521d\u304b\u3089\u305a\u3063\u3068\u540c\u3058\u3067\u30013\u30d0\u30a4\u30c8\u306e\u30c7\u30fc\u30bf\u306f\u5909\u5316\u3057\u3066\u3044\u308b\u3002
    3\u30d0\u30a4\u30c8\u306e\u30c7\u30fc\u30bf\u3092\u9001\u4fe1\u3059\u308b\u3053\u3068\u3067\u4f55\u3089\u304b\u306e\u60c5\u5831\u3092\u5916\u90e8\u5275\u51fa\u3057\u3066\u3044\u308b\u3082\u306e\u3068\u601d\u308f\u308c\u308b\u306e\u3067\u3001\u3053\u3053\u3092\u89e3\u6790\u3057\u3066\u4f55\u304c\u9001\u3089\u308c\u3066\u3044\u308b\u306e\u304b\u898b\u3066\u3044\u304f\u3002<\/p>\n\n\n\n

    $17<\/code>\u3068$3<\/code>\u306e\u9001\u4fe1\u3092\u3057\u3066\u3044\u308b\u95a2\u6570\u306fexfiltrate<\/code>\uff08\u305d\u306e\u307e\u3093\u307e\u3060\u2026\uff09\u3067\u3001$3<\/code>\u306e\u9001\u4fe1\u30c7\u30fc\u30bf\u306b\u306a\u3063\u3066\u3044\u308b\u30d0\u30c3\u30d5\u30a1\u3092\u78ba\u8a8d\u3059\u308b\u3068\u30013\u30d0\u30a4\u30c8\u306e\u3046\u3061\u5148\u306e2\u30d0\u30a4\u30c8\u306fexfiltrate<\/code>\u306e\u7b2c3\u5f15\u6570\u3001\u5f8c\u308d1\u30d0\u30a4\u30c8\u306fexfiltrate<\/code>\u306e\u7b2c2\u5f15\u6570\u3067\u6307\u5b9a\u3055\u308c\u3066\u3044\u308b\u3002<\/p>\n\n\n

    \n
    \"\"<\/a><\/figure>\n<\/div>\n\n\n

    \u3053\u308c\u3089\u306e\u51fa\u5143\u3092\u305f\u3069\u308b\u3068\u3001read<\/code>\u3067\u7e70\u308a\u8fd4\u3057\u8aad\u307f\u8fbc\u3093\u3060\u30c7\u30fc\u30bf\u306e\u66f8\u304d\u8fbc\u307f\u5148\u3067\u3042\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002\u66f8\u304d\u8fbc\u307f\u5148\u306e\u5148\u982d\u306frsp<\/code>\u3067\u3001\u305d\u3053\u304b\u308918\u30d0\u30a4\u30c8\u5148\u304b\u3089\u304cexfiltrate<\/code>\u3067\u306e\u9001\u4fe1\u30c7\u30fc\u30bf\u306b\u306a\u308b\u3002<\/p>\n\n\n

    \n
    \"\"<\/a><\/figure>\n<\/div>\n\n\n

    \u3067\u306fread<\/code>\u3067\u8aad\u307f\u8fbc\u3093\u3067\u3044\u308b\u3082\u306e\u306f\u4f55\u304b\u3002read<\/code>\u306e\u7b2c1\u5f15\u6570fd\u3092\u8ffd\u3044\u304b\u3051\u308b\u3068\u3001source<\/code>\u95a2\u6570\u306e\u8fd4\u308a\u5024\u3067\u3042\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u306e\u3067\u3001source<\/code>\u95a2\u6570\u3092\u8aad\u307f\u89e3\u304f\u3068\u3001\/dev\/input\/event1<\/code>\uff08\u30ad\u30fc\u30dc\u30fc\u30c9\uff09\u3092\u958b\u3044\u3066\u3044\u308b\u3053\u3068\u304c\u308f\u304b\u308b\u3002\u305d\u306e\u5f8c\u306eioctl<\/code>\u306e\u610f\u5473\u304c\u308f\u304b\u3089\u306a\u304b\u3063\u305f\u306e\u3067\u8ab0\u304b\u308f\u304b\u308b\u4eba\u6559\u3048\u3066\u307b\u3057\u3044\u3002<\/p>\n\n\n\n

    \/dev\/input\/event1<\/code>\u304b\u3089\u5f97\u3089\u308c\u308b\u30c7\u30fc\u30bf\u306finput_event<\/code>\u69cb\u9020\u4f53\u3068\u306a\u308b\u3002<\/p>\n\n\n\n

    struct input_event {\n        struct timeval time;\n        __u16 type;\n        __u16 code;\n        __s32 value;\n};<\/code><\/pre>\n\n\n\n
    struct timeval<\/code>\u306f128bit(16byte)\u306e\u305f\u3081\u3001exfiltrate<\/code>\u306b\u6e21\u3055\u308c\u308b\u30c7\u30fc\u30bf\u306f\u3001code<\/code>\u3068value<\/code>\uff08\u306e\u5148\u982d1\u30d0\u30a4\u30c8\uff09\u306b\u306a\u308b\u3053\u3068\u304c\u308f\u304b\u3063\u305f\u3002code<\/code>\u306e\u5024\u306finput-event-code.h<\/code><\/a>\u306b\u30ad\u30fc\u30dc\u30fc\u30c9\u306e\u30ad\u30fc\u3068\u306e\u5bfe\u5fdc\u304c\u5b9a\u7fa9\u3055\u308c\u3066\u3044\u308b\u3002value<\/code>\u306f\u30ad\u30fc\u306e\u72b6\u614b\u3092\u8868\u3057\u30010\u304cup\u30011\u304cdown\u30012\u304chold\u3068\u306a\u308b\u3002\u3061\u306a\u307f\u306b\u3001\u5404\u30ad\u30fc\u3092\u62bc\u3057\u305f\u3068\u304d\u306ecode<\/code>\u306e\u5024\u306fevtest<\/code>\u30b3\u30de\u30f3\u30c9\u3067\u78ba\u8a8d\u3067\u304d\u308b\u3002<\/p>\n\n\n\n
    \"\"<\/a><\/figure>\n\n\n\n
    pcap\u304b\u30893\u30d0\u30a4\u30c8\u306e\u30c7\u30fc\u30bf\u90e8\u5206\u3092\u629c\u304d\u51fa\u3059\u3068\u30ad\u30fc\u30dc\u30fc\u30c9\u306e\u5165\u529b\u5c65\u6b74\u60c5\u5831\u3068\u306a\u308b\u3002\u4f7f\u7528\u3055\u308c\u3066\u3044\u305f\u306e\u304c\u65e5\u672c\u8a9e\u30ec\u30a4\u30a2\u30a6\u30c8\u306e\u30ad\u30fc\u30dc\u30fc\u30c9\u3067\u3042\u308b\u3053\u3068\u3001NumLock\u304cOff\u306e\u3068\u304d\u306e\u30ad\u30fc\u30d1\u30c3\u30c91\u306fEnd\u3067\u3042\u308b\u3053\u3068\u306b\u6ce8\u610f\u3059\u308b\u3068\u3001\u4ee5\u4e0b\u306e\u6587\u5b57\u5217\u304c\u62bd\u51fa\u3067\u304d\u308b\u3002<\/p>\n\n\n\n
    CakeCTF{b3_c4r3fuL_0f_m4l1c10us_k3yL0gg3r}\nI hope nobody is seeing my screen...<\/code><\/pre>\n\n\n\n
    Flag: CakeCTF{b3_c4r3fuL_0f_m4l1c10us_k3yL0gg3r}<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"
    \u53c2\u52a0\u3057\u30662\u554f\u89e3\u3044\u305f\u306e\u3067writeup<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"cybocfi_hide_featured_image":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-712","post","type-post","status-publish","format-standard","hentry","category-1"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/posts\/712","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/comments?post=712"}],"version-history":[{"count":7,"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/posts\/712\/revisions"}],"predecessor-version":[{"id":726,"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/posts\/712\/revisions\/726"}],"wp:attachment":[{"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/media?parent=712"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/categories?post=712"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/emeth.jp\/diary\/wp-json\/wp\/v2\/tags?post=712"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}