{"id":311,"date":"2024-12-12T22:19:13","date_gmt":"2024-12-12T14:19:13","guid":{"rendered":"http:\/\/8.141.27.105\/?p=311"},"modified":"2025-01-20T16:36:02","modified_gmt":"2025-01-20T08:36:02","slug":"ctfpwn%e6%a0%88%e5%88%a9%e7%94%a8%e6%a0%88%e8%bf%81%e7%a7%bb","status":"publish","type":"post","link":"http:\/\/n0ps1ed.top\/index.php\/2024\/12\/12\/ctfpwn%e6%a0%88%e5%88%a9%e7%94%a8%e6%a0%88%e8%bf%81%e7%a7%bb\/","title":{"rendered":"\u6808\u8fc1\u79fb"},"content":{"rendered":"\n

\u4e00\u822c\u6765\u8bf4\uff0c\u6bd4\u5982\u8981\u6784\u9020system(bin\/sh)\u7684rop\u94fe\uff0c\u53ea\u9700\u8981\u628aret\u8986\u76d6\u4e3asystem\uff0c\u7136\u540e\u9694\u4e00\u4e2ap32(0),\u518d\u586b\u5165binsh\u5b57\u7b26\u4e32\u5730\u5740\u5c31\u884c\uff0c\u4f46\u662f\u5982\u679c\u6ea2\u51fa\u957f\u5ea6\u53ea\u80fd\u5230ret\u7684\u8bdd\uff0c\u5c31\u53ea\u80fd\u505a\u5230\u628aret\u8986\u76d6\u4e3asystem\uff0c\u540e\u9762\u7684\u5c31\u586b\u4e0d\u4e86\u4e86\uff0c\u600e\u4e48\u529e\uff1f\u6808\u8fc1\u79fb\u901a\u5e38\u5c31\u4f7f\u7528\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\u3002<\/p>\n\n\n\n

\u4e00\u4e2a\u51fd\u6570\u6267\u884c\u5b8c\u540e\uff0c\u4f1a\u4f7f\u7528leave\u6307\u4ee4\u6765\u5220\u9664\u5b83\u7684\u6808\u5e27\uff0c\u4e5f\u5c31\u662fmov esp,ebp;pop ebp;\u8fd9\u4e2a\u65f6\u5019ebp\u4f1a\u56de\u5230\u7236\u51fd\u6570\u7684ebp\u5904\uff0c\u7136\u540eesp\u5c31\u4f1a\u4e0a\u79fb\u5230ret\u4f4d\u7f6e\u3002\u8fd9\u5c31\u662f\u4e00\u4e2a\u5b8c\u6574\u7684leave\u64cd\u4f5c\u3002<\/p>\n\n\n\n

\u5982\u679c\u6211\u4eec\u4fee\u6539ebp\u7684\u5185\u5bb9\uff0c\u90a3pop ebp\u540e\uff0cebp\u5c31\u4f1a\u88ab\u52ab\u6301\u5230\u6307\u5b9a\u5730\u65b9\uff0c\u5982\u679c\u6b64\u65f6\u518d\u6765\u4e00\u4e2aleave\u6307\u4ee4\uff0c\u7531\u4e8emov esp,ebp\u3002\u6240\u4ee5esp\u5c31\u4f1a\u88ab\u52ab\u6301\u5230\u4e0eebp\u88ab\u52ab\u6301\u5230\u7684\u4e00\u6837\u7684\u4f4d\u7f6e\uff0c\u7136\u540epop ebp\u3002\u6b64\u65f6esp\u5c31\u6210\u529f\u88ab\u52ab\u6301\u4e86\uff0c\u5c31\u53ef\u4ee5\u8fdb\u4e00\u6b65\u5f71\u54cd\u5230eip\u3002<\/p>\n\n\n\n

\u6808\u8fc1\u79fb\u7684\u601d\u8def\u662f\uff1a<\/p>\n\n\n\n

1.\u5bfb\u627e\u53ef\u52ab\u6301\u5230\u7684\u4f4d\u7f6e\uff08\u53ef\u5199\uff09<\/p>\n\n\n\n

2.\u5f97\u5230\u52ab\u6301\u5230\u7684\u4f4d\u7f6e\u7684\u5730\u5740<\/p>\n\n\n\n

3.\u5199exp<\/p>\n\n\n\n

\u63a5\u4e0b\u6765\u770b\u4f8b\u9898\uff0cCTFSHOW PWN\u5165\u95e8 PWN75<\/p>\n\n\n\n

\u5173\u952e\u70b9\u5b9a\u4f4d\u5728ctfshow\u51fd\u6570\u4e2d\uff1a<\/p>\n\n\n\n

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

\u5b9a\u4e49\u4e86\u4e00\u4e2a\u6808\u4e0a\u53d8\u91cfs\uff0c\u7136\u540eread\u4e24\u6b21\uff0c\u6700\u540eprintf\u51fas\u7684\u5185\u5bb9<\/p>\n\n\n\n

\u8fd9\u91cc\u9009\u62e9\u5c31\u52ab\u6301\u5230s\u8fd9\u91cc\u3002<\/p>\n\n\n\n

\u9996\u5148\u770b\u4e00\u4e0b\u600e\u4e48\u5f97\u5230s\u7684\u771f\u5b9e\u5730\u5740\uff0cprintf\u4f1a\u8bfb\u5230\/0\u4e3a\u6b62\uff0c\u5982\u679c\u8f93\u5165\u586b\u6ee1\uff0c\u4e0d\u586b\/0\u7684\u8bdd\uff0c\u5c31\u4f1a\u628a\u63a5\u4e0b\u6765\u7684\u5185\u5bb9\u4e5f\u8bfb\u51fa\u6765\uff0c\u628as\u768436\u5b57\u8282\u586b\u6ee1\u7684\u8bdd\uff0c\u63a5\u4e0b\u6765\u5c31\u662f\u5b83\u7684ebp\uff0c\u91cc\u9762\u662f\u65e7ebp\u7684\u5185\u5bb9\uff0c\u6240\u4ee5\u53ef\u4ee5\u628a\u65e7ebp\u5185\u5bb9\u8bfb\u51fa\u6765\uff0c\u7136\u540e\u518d\u786e\u5b9as\u8ddd\u79bb\u65e7ebp\u7684\u8ddd\u79bb\uff0c\u5c31\u53ef\u4ee5\u5f97\u5230s\u7684\u5730\u5740\u3002<\/p>\n\n\n\n

\u5148\u5224\u65ads\u7684\u5927\u5c0f\uff0cida\u7f16\u8bd1\u51fa\u6765\u6709\u77db\u76fe\uff1a<\/p>\n\n\n\n

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

\u53ef\u4ee5\u770b\u523044\u65f6\u5019\u53d1\u751f\u4e86\u9519\u8bef\uff0c\u51cf\u53bbebp\u76844\u5b57\u8282\uff0cs\u7684\u5927\u5c0f\u662f40<\/p>\n\n\n\n

\u5148\u901a\u8fc7\u7b2c\u4e00\u4e2aread\u5f97\u5230\u65e7ebp\u5730\u5740\uff1a<\/p>\n\n\n\n

payload1=b’a’*39+b’B’<\/p>\n\n\n\n

p.recvuntil(“ame:”)<\/p>\n\n\n\n

p.send(payload1)<\/p>\n\n\n\n

p.recvuntil(b”B”)<\/p>\n\n\n\n

oldebp=u32(p.recv(4))<\/p>\n\n\n\n

print(hex(oldebp))<\/p>\n\n\n\n

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

\u7136\u540e\u8ba1\u7b97s\u79bb\u65e7ebp\u591a\u5c11\uff1a<\/p>\n\n\n\n

\u7ed9ctfshow\u51fd\u6570\u4e0b\u65ad\u70b9<\/p>\n\n\n\n

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

r\uff1a<\/p>\n\n\n\n

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

ebp\u57280xffffcfe8\u5904\u5b58\u4e860xffffcff8,\u4e5f\u5c31\u662f\u65e7ebp\u662f0xffffcff8,\u4e24\u8005\u9694\u4e860x10,\u800cs\u79bb0xffffcfe8\uff08\u65b0ebp\uff0940\u4e2a\u5b57\u8282\uff0c\u90a3\u4e00\u5171\u5c31\u662f56\u5b57\u8282\u3002<\/p>\n\n\n\n

payload\u6784\u601d\u5982\u4e0b\uff1a<\/p>\n\n\n\n

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

payload2=p32(0)+p32(system)+p32(0)+p32(binshaddr)+b”\/bin\/sh\\x00″+b’a’*20+p32(oldebp-56)+p32(leave)<\/p>\n\n\n\n

\u7136\u540e\u5c31\u662f\u53bb\u627eleave\u548csystem\u7684\u4f4d\u7f6e\u5c31\u884c\uff1a<\/p>\n\n\n\n

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

\u4f46\u662f\u59cb\u7ec8\u6253\u4e0d\u901a\uff0c\u6700\u540e\u53d1\u73b0\u539f\u56e0\u662fb’a’*20,\u5e94\u8be5\u662f*16\uff0c\u6211\u4e5f\u4e0d\u77e5\u9053\u4e3a\u4ec0\u4e48\u4e0d\u662f20\uff0c\u4ee5\u540e\u8fd8\u662f\u76f4\u63a5\u7528.ljust\u6765\u8865\u9f50\u6700\u597d<\/p>\n\n\n\n

\u601d\u8003\uff1a\u65e2\u7136\u90fd\u80fd\u77e5\u9053s\u7684\u5730\u5740\uff0c\u4e3a\u4ec0\u4e48\u4e0d\u76f4\u63a5ret\u56de\u6765\u6267\u884c\uff1f<\/p>\n\n\n\n

\u6709\u8fd9\u4e2a\u95ee\u9898\u662f\u56e0\u4e3a\u6211\u6ca1\u628aeip\u8ddfesp\u3001shellcode\u548crop\u94fe\u641e\u6e05\u695a\uff0c\u901a\u5e38ret\u53bb\u7684\u5730\u65b9\u662fshellcode\uff0c(ret\u662f\u628a\u503cpop\u7ed9eip\uff0c\u540e\u9762\u5c31\u662feip\u4e0d\u65ad\u4e0a\u79fb\u6267\u884c\u547d\u4ee4)\u662feip\u76f4\u63a5\u5c31\u80fd\u6267\u884c\u7684\u4ee3\u7801\u4f4d\u7f6e\uff0c\u4f46\u662f\u8fd9\u91cc\u7531\u4e8eNX\u7684\u586b\u4e0d\u4e86shellcode\uff0c\u800c\u4e14\u586b\u5145\u7684\u4e5f\u4e0d\u662fshellcode\u800c\u662frop\u94fe\uff0c\u6240\u4ee5\u5f97\u7528esp\u6765\u95f4\u63a5\u8ba9eip\u6267\u884c\u60f3\u8981\u7684\u547d\u4ee4\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

\u4e00\u822c\u6765\u8bf4\uff0c\u6bd4\u5982\u8981\u6784\u9020system(bin\/sh)\u7684rop\u94fe\uff0c\u53ea\u9700\u8981\u628aret\u8986\u76d6\u4e3asystem\uff0c\u7136\u540e\u9694\u4e00\u4e2ap32 […]<\/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":[14,16,15],"class_list":["post-311","post","type-post","status-publish","format-standard","hentry","category-17","category-13","tag-pwn","tag-rop","tag-15"],"_links":{"self":[{"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts\/311","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=311"}],"version-history":[{"count":3,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts\/311\/revisions"}],"predecessor-version":[{"id":827,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/posts\/311\/revisions\/827"}],"wp:attachment":[{"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/media?parent=311"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/categories?post=311"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/n0ps1ed.top\/index.php\/wp-json\/wp\/v2\/tags?post=311"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}