CHROOT\u5c31\u662fChange Root\uff0c\u4e5f\u5c31\u662f\u6539\u53d8\u7a0b\u5f0f\u6267\u884c\u65f6\u6240\u53c2\u8003\u7684\u6839\u76ee\u5f55\u4f4d\u7f6e\u3002<\/p>\n
\u4e00\u822c\u7684\u76ee\u5f55\u67b6\u6784\uff1a
\n\/
\n\/bin
\n\/sbin
\n\/usr\/bin
\n\/home<\/p>\n
CHROOT\u7684\u76ee\u5f55\u67b6\u6784\uff1a
\n\/hell\/
\n\/hell\/bin
\n\/hell\/usr\/bin
\n\/hell\/home
\n* \u4e3a\u4f55\u8981CHROOT\uff1f<\/p>\n
1.\u9650\u5236\u88abCHROOT\u7684\u4f7f\u7528\u8005\u6240\u80fd\u6267\u884c\u7684\u7a0b\u5f0f\uff0c\u5982SetUid\u7684\u7a0b\u5f0f\uff0c\u6216\u662f\u4f1a\u9020\u6210Load \u7684 Compiler\u7b49\u7b49\u3002
\n2.\u9632\u6b62\u4f7f\u7528\u8005\u5b58\u53d6\u67d0\u4e9b\u7279\u5b9a\u6863\u6848\uff0c\u5982\/etc\/passwd\u3002
\n3.\u9632\u6b62\u5165\u4fb5\u8005\/bin\/rm -rf \/\u3002
\n4.\u63d0\u4f9bGuest\u670d\u52a1\u4ee5\u53ca\u5904\u7f5a\u4e0d\u4e56\u7684\u4f7f\u7528\u8005\u3002
\n5.\u589e\u8fdb\u7cfb\u7edf\u7684\u5b89\u5168\u3002<\/p>\n
* \u8981\u5982\u4f55\u5efa\u7acbCHROOT\u7684\u73af\u5883\uff1f
\n1.chroot()\u8fd9\u4e2afunction\uff1a
\nchroot(PATH)\u8fd9\u4e2afunction\u5fc5\u987b\u5177\u6709 root \u7684\u8eab\u4efd\u624d\u80fd\u6267\u884c\uff0c\u6267\u884c\u5f8c\u4f1a\u5c06\u6839\u76ee\u5f55\u5207\u6362\u5230 PATH\u6240\u6307\u5b9a\u7684\u5730\u65b9\u3002
\n2.login\u7684\u8fc7\u7a0b\uff1a
\n\u4f7f\u7528\u8005\u65e0\u8bba\u662f\u4ececonsole\u6216\u662ftelnet\u8fdb\u5165\uff0c\u90fd\u5fc5\u987b\u6267\u884c\/usr\/bin\/login\u6765
\n\u51b3\u5b9a\u662f\u5426\u80fd\u8fdb\u5165\u7cfb\u7edf\uff0c\u800clogin\u6240\u505a\u7684\u52a8\u4f5c\u5927\u81f4\u662f\uff1a
\n(1)\u5370\u51falogin\u7684\u63d0\u793a\u7b26\u53f7\uff0c\u7b49\u5f85\u4f7f\u7528\u8005\u8f93\u5165\u5bc6\u7801\u3002
\n(2)\u68c0\u67e5\u5bc6\u7801\u662f\u5426\u6b63\u786e\uff0c\u9519\u8bef\u7684\u8bdd\u56de\u5230(1)\u3002
\n(3)\u6b63\u786e\u7684\u8bdd\u4ee5setuid()\u6765\u6539\u53d8\u8eab\u4efd\u4e3alogin_user\u3002
\n(4)\u4ee5exec()\u6267\u884cuser\u7684shell\u3002
\n\u56e0\u6b64\u6211\u4eec\u5fc5\u987b\u5148\u4fee\u6539\/usr\/bin\/login\u7684source code\uff0c\u8ba9login\u5728(2)\u5230(3)
\n\u7684\u4e2d\u95f4\u6267\u884cchroot($CHROOT_PATH)\u7684\u52a8\u4f5c\uff0c\u5df2\u8fbe\u5230CHROOT\u7684\u76ee\u7684\uff0c\u5e76\u4ee5\u4fee
\n\u6539\u8fc7\u7684login\u66ff\u4ee3\u539f\u5148\u7684\/usr\/bin\/login\u3002
\n(5)\u7a0d\u5fae\u597d\u4e00\u70b9\u7684\u65b9\u6cd5\u5fc5\u987b\u5728\u505achroot()\u4e4b\u524d\u68c0\u67e5login
\nuser\u7684group\uff0c\u5982\u679c\u6709\u67d0\u4e2a\u7279\u5b9a\u7684group(\u5982chrootgrp)
\n\u624d\u6267\u884cchroot()\uff0c\u4e0d\u7136\u6240\u6709\u7684\u4eba\u90fd\u4f1a\u88abchroot\u4e86\u3002<\/p>\n
3.\u5efa\u7acbCHROOT\u6240\u9700\u7684\u73af\u5883\uff1a
\n(1)\u5fc5\u987b\u5177\u5907\u7684\u76ee\u5f55\uff1a(\u5047\u8bbe$CHROOT\u4e3a\u5e0c\u671b\u5efa\u7acb\u7684\u8def\u5f84)
\n$CHROOT\/etc $CHROOT\/lib $CHROOT\/bin
\n$CHROOT\/sbin $CHROOT\/usr\/lib $CHROOT\/usr\/bin
\n$CHROOT\/usr\/bin $CHROOT\/usr\/local $CHROOT\/home
\n(2)\u4ed4\u7ec6\u5ba1\u67e5\/etc\u4e2d\u7684\u6863\u6848\uff0c\u9700\u5177\u5907\u6267\u884c\u7a0b\u5f0f\u65f6\u6240\u9700\u7684\u6863
\n\u6848\uff0c\u5982passwd\uff0cgroups\uff0chosts\uff0cresolv.conf\u7b49\u7b49\u3002
\n(3)\u62ff\u6389\u4e0d\u60f3\u7ed9\u7684\u6267\u884c\u6863\uff0c\u5982su\uff0csudo\u7b49SetUid\u7684\u7a0b\u5f0f\uff0c
\n\u4ee5\u53cacompiler\u751a\u81f3telnet\u3002
\n(4)\u6d4b\u8bd5\u4e00\u4e0b\uff0c\u4ee5root\u8eab\u4efd\u6267\u884c chroot $CHROOT \/bin\/sh
\n\u5373\u53ef\u8fdb\u5165CHROOT\u73af\u5883\u4e2d\u3002(man chroot for details)<\/p>\n
4.\u5728console\u6216\u662f\u4ee5telnet\u8fdb\u5165\u8bd5\u8bd5\u3002<\/p>\n
5.Username\/Password Resolve\u7684\u8003\u91cf\uff1a
\n\u5728CHROOT\u65f6\u4f60\u53ef\u80fd\u4e0d\u5e0c\u671b\u88abCHROOT\u7684\u4f7f\u7528\u8005(\u4ee5\u5f8c\u7b80\u79f0CHROOTer)\u80fd\u62ff\u5230\/etc\/passwd\u6216\u662f\/etc\/shadow\u7b49\u6863\u6848\uff0c\u5c24\u5176\u662f\u6709root\u5bc6\u7801\u7684\u3002\u4ee5\u4e0b\u6709\u4e09\u79cd\u60c5\u5f62\uff1a
\n(1)\/etc\/passwd\u8ddf $CHROOT\/etc\/passwd\u76f8\u540c\uff1a
\n\u8fd9\u662f\u6700\u5dee\u7684\u4f5c\u6cd5\uff0c\u56e0\u4e3a\u4e00\u6765\u88abCHROOTer\u6709\u673a\u4f1a\u5f97\u5230root
\n\u7684encrypted password\uff0c\u4e8c\u6765\u8981\u4fdd\u6301\/etc\/passwd\u53ca
\n$CHROOT\/etc\/passwd\u7684\u540c\u6b65\u6027\u662f\u4e2a\u5927\u95ee\u9898\u3002\u56e0\u4e3a
\n\/usr\/bin\/login\u53c2\u8003\u7684\u662f\/etc\/passwd\uff0c\u53ef\u662f\u4e00\u65e6
\nCHROOTer\u88abchroot\u5f8c\u6267\u884cpasswd\u65f6\uff0c\u4ed6\u6240\u6267\u884c\u7684
\npasswd\u6240\u66f4\u6539\u7684\u5c06\u662f$CHROOT\/etc\/passwd\u3002
\n(2)\/etc\/passwd\u8ddf$CHROOT\/etc\/passwd\u4e0d\u540c\uff1a
\n\u4f60\u53ef\u4ee5\u628a$CHROOT\/etc\/passwd\u4e2d\u7684\u91cd\u8981\u4eba\u7269(\u5982root)
\n\u7684\u5bc6\u7801\u62ff\u6389\uff0c\u7136\u5f8c\u4ee5\u6bd4\u8f83\u590d\u6742\u7684\u65b9\u6cd5\u4fee\u6539
\n\/usr\/bin\/login\uff1a
\nif (has_chroot_group) {
\nre-load $CHROOT\/etc\/passwd
\nif (password is valid) {
\nchroot($CHROOT)
\nexec(shell)
\n} else logout()
\n}
\n\u6b64\u6cd5\u7684\u597d\u5904\u662f\u4f60\u53ef\u4ee5\u5c06\/etc\/passwd\u8ddf
\n$CHROOT\/etc\/passwd\u5206\u5f00\u6765\u3002\/etc\/passwd\u53ea\u5f71\u54cd
\nCHROOTer\u5728login\u65f6\u6240\u4f7f\u7528\u7684username\uff0c\u5176\u4ed6\u5982
\npassword\u751a\u81f3uid\uff0cgid\uff0cshell\uff0chome\u7b49\u7b49\u90fd\u662f\u53c2
\n\u8003$CHROOT\/etc\/passwd\u7684\u3002
\n\u7f3a\u70b9\u662f\u4f60\u5176\u4ed6\u7684daemon\u5982ftpd\uff0chttpd\u90fd\u5fc5\u987b\u505a\u76f8\u540c
\n\u7684\u4fee\u6539\u624d\u80fd\u6b63\u786e\u53d6\u7684CHROOTer\u7684\u8d44\u8baf\uff0c\u800c\u4e14\u4f60\u5728\u628a\u4e00
\n\u4e2auser\u52a0\u5165\u6216\u79fb\u51fachroot_group\u65f6\u90fd\u5fc5\u987b\u66f4\u6539
\n\/etc\/passwd\u8ddf$CHROOT\/etc\/passwd\u3002<\/p>\n
(3)\u4f7f\u7528NIS\/YP\uff1a
\n\u6b64\u6cd5\u5927\u6982\u662f\u6700\u7b80\u5355\uff0c\u4e14\u9ebb\u70e6\u6700\u5c11\u7684\u4e86\u3002\u56e0\u4e3a\u4e00\u5207\u7684user
\ninformation\u90fd\u7ecf\u8fc7NIS Bind\u6765\u53d6\u5f97\uff0c\u4e0d\u4f46\u53ef\u4ee5\u4fdd\u62a4\u4f4f
\nroot\u7684\u5bc6\u7801\uff0c\u4e5f\u7701\u53bb\/etc\/passwd\u8ddf
\n$CHROOT\/etc\/passwd\u540c\u6b65\u7ba1\u7406\u4e0a\u7684\u95ee\u9898\u3002\u4e0d\u53ea\u662f
\npasswd\uff0c\u8fde\u5176\u4ed6\u5982groups\uff0chosts\uff0cservices\uff0c
\naliases\u7b49\u7b49\u90fd\u53ef\u4ee5\u4e00\u5e76\u89e3\u51b3\u3002<\/p>\n
* \u5176\u4ed6\u5fc5\u987b\u8003\u8651\u7684\u95ee\u9898\uff1a
\n1.\u6267\u884c\u6863\u7684\u540c\u6b65\u6027\uff1a
\n\u518d\u66f4\u65b0\u7cfb\u7edf\u6216\u662f\u66f4\u65b0\u8f6f\u4f53\u65f6\uff0c\u5fc5\u987b\u8003\u8651\u5230\u4e00\u5e76\u66f4\u6362
\n$CHROOT\u76ee\u5f55\u4e0b\u7684\u6863\u6848\uff0c\u5c24\u5176\u5982SunOS\u6216\u662fBSD\u7b49\u4f1a\u7528
\nnlist()\u6765\u53d6\u5f97Kernel Information\u7684\uff0c\u5728\u66f4\u65b0kernel
\n\u65f6\u5fc5\u987b\u66f4\u65b0$CHROOT\u4e0b\u7684kernel\u3002
\n2.\/dev\u7684\u95ee\u9898\uff1a
\n\u4e00\u822c\u800c\u8a00\u4f60\u5fc5\u987b\u7528local loopback NFS\u5c06\/dev read-write mount\u5230$CHROOT\/dev\u4ee5\u4f7f\u5f97\u4e00\u822cuser\u8ddfCHROOTer\u53ef\u4ee5\u4e92\u76f8write\u4ee5\u53ca\u89e3\u51b3devices\u540c\u6b65\u6027\u7684\u95ee\u9898\u3002
\n3.\/proc\u7684\u95ee\u9898\uff1a
\n\u5728Linux\u6216\u662fSYSV\u6216\u662f4.4BSD\u7684\u7cfb\u7edf\u4e0a\u8bb8\u591a\u7a0b\u5f0f\u4f1a\u53bb
\n\u53c2\u8003\/proc\u7684\u8d44\u6599\uff0c\u4f60\u5fc5\u987b\u4e5f\u5c06\/proc mount\u5230
\n$CHROOT\/proc\u3002
\n4.\/var\u7684\u95ee\u9898\uff1a
\n\u4e00\u822c\u800c\u8a00\/var\u4e5f\u662f\u7528local loopback NFS read-write
\nmount\u5230$CHROOT\/var\u4e0b\uff0c\u4ee5\u89e3\u51b3spool\u540c\u6b65\u6027\u7684\u95ee\u9898\uff0c
\n\u5426\u5219\u4f60\u53ef\u80fd\u5fc5\u987b\u8981\u4fee\u6539lpd\u6216\u662fsendmail\u7b49daemon\uff0c
\n\u4e0d\u7136\u4ed6\u4eec\u662f\u4e0d\u77e5\u9053$CHROOT\/var\u4e0b\u4e5f\u6709spool\u7684\u5b58\u5728\u3002
\n5.Daemon\u7684\u95ee\u9898\uff1a
\n\u4f60\u5fc5\u987b\u4fee\u6539\u4e00\u4e9b\u8ddf\u4f7f\u7528\u8005\u76f8\u5173\u7684Daemon\u5982ftpd\uff0chttpd
\n\u4ee5\u4f7f\u8fd9\u4e9bdaemon\u80fd\u627e\u5230\u6b63\u786e\u7684user home\u3002<\/p>\n
* CHROOT\u65e0\u6cd5\u89e3\u51b3\u7684\u5b89\u5168\u95ee\u9898\uff1a
\n1.\u4e0d\u5c0f\u5fc3\u6216\u662f\u5fd8\u8bb0\u62ff\u6389SetUid\u7684\u7a0b\u5f0f\uff1a
\nCHROOTer\u8fd8\u662f\u6709\u673a\u4f1a\u5229\u7528SetUid\u7684\u7a0b\u5f0f\u6765\u53d6\u5f97root\u7684
\n\u6743\u9650\uff0c\u4e0d\u8fc7\u56e0\u4e3a\u4f60\u5df2\u7ecf\u5c06\u4ed6CHROOT\u4e86\uff0c\u6240\u4ee5\u6240\u80fd\u5f71\u54cd\u5230
\n\u7684\u53ea\u6709$CHROOT\/\u76ee\u5f55\u4ee5\u4e0b\u7684\u6863\u6848\uff0c\u5c31\u7b97\u4ed6\u6765\u4e2a
\n\"\/bin\/rm -rf \/\" \u4e5f\u4e0d\u6015\u4e86\u3002
\n\u4e0d\u8fc7\u5176\u4ed6root\u80fd\u505a\u7684\u4e8b\u8fd8\u662f\u9632\u4e0d\u4e86\uff0c\u5982\u5229\u7528tcpdump\u6765
\n\u7a83\u542c\u8be5localnet\u4e2d\u7684\u901a\u8baf\u5e76\u53d6\u5f97\u5728\u8be5localnet\u4e0a\u5176\u4ed6
\n\u673a\u5668\u7684\u5e10\u53f7\u5bc6\u7801\uff0creboot\u673a\u5668\uff0c\u66f4\u6539NIS\u7684\u8d44\u6599\uff0c\u66f4\u6539
\n\u5176\u4ed6\u6ca1\u6709\u88abCHROOT\u7684\u5e10\u53f7\u7684\u5bc6\u7801\u85c9\u4ee5\u53d6\u5f97\u4e00\u822c\u5e10\u53f7(\u6240
\n\u4ee5root\u4e0d\u53ef\u52a0\u5165NIS\u4e2d)\u7b49\u7b49\u3002
\n(\u6b64\u65f6\u5c31\u5fc5\u987b\u85c9\u7531securetty\u6216\u662flogin.access\u6216\u662f\u5c06
\nwheel group\u62ff\u51faNIS\u6765\u9632\u6b62\u5176login as root)
\n2.\u5df2\u8f7d\u5165\u8bb0\u5fc6\u4f53\u4e2d\u7684Daemon\uff1a
\n\u5bf9\u65bc\u90a3\u4e9b\u4e00\u5f00\u673a\u5c31\u6267\u884c\u7684\u7a0b\u5f0f\u5982sendmail\uff0chttpd\uff0c
\ngopherd\uff0cinetd\u7b49\u7b49\uff0c\u5982\u679c\u8fd9\u4e9bdaemon\u6709hole(\u5982
\nsendmail)\uff0c\u90a3hacker\u53ea\u8981\u7834\u89e3\u8fd9\u4e9bdaemon\u8fd8\u662f\u53ef\u4ee5\u53d6
\n\u5f97root\u6743\u9650\u3002<\/p>\n
* \u7ed3\u8bba\uff1a
\nCHROOT\u53ef\u4ee5\u589e\u8fdb\u7cfb\u7edf\u7684\u5b89\u5168\u6027\uff0c\u9650\u5236\u4f7f\u7528\u8005\u80fd\u505a\u7684\u4e8b\uff0c
\n\u4f46\u662fCHROOT Is Not Everything\uff0c\u56e0\u4e3a\u8fd8\u662f\u6709\u5176\u4ed6\u7684
\n\u6f0f\u6d1e\u7b49\u8457hacker\u6765\u627e\u51fa\u6765\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
CHROOT\u5c31\u662fChange Root\uff0c\u4e5f\u5c31\u662f\u6539\u53d8\u7a0b\u5f0f\u6267\u884c\u65f6\u6240\u53c2\u8003\u7684\u6839\u76ee\u5f55\u4f4d\u7f6e\u3002 \u4e00\u822c\u7684\u76ee\u5f55\u67b6\u6784\uff1a \/ \/bi […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-592","post","type-post","status-publish","format-standard","hentry","category-Technical_literature"],"views":3041,"_links":{"self":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/posts\/592","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/comments?post=592"}],"version-history":[{"count":0,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/posts\/592\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/media?parent=592"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/categories?post=592"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.datarelab.com\/blog\/wp-json\/wp\/v2\/tags?post=592"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}