{"id":92,"date":"2023-06-05T12:46:57","date_gmt":"2023-06-05T04:46:57","guid":{"rendered":"http:\/\/pro369.com\/linux\/?p=92"},"modified":"2019-05-21T08:43:54","modified_gmt":"2019-05-21T08:43:54","slug":"centos-55-%e7%b3%bb%e7%b5%b1%e5%ae%89%e5%85%a8%e9%85%8d%e7%bd%ae","status":"publish","type":"post","link":"https:\/\/por.tw\/linux\/centos-55-%e7%b3%bb%e7%b5%b1%e5%ae%89%e5%85%a8%e9%85%8d%e7%bd%ae\/","title":{"rendered":"CentOS 5.5 \u7cfb\u7d71\u5b89\u5168\u914d\u7f6e"},"content":{"rendered":"

CentOS 5.5 \u7cfb\u7d71\u5b89\u5168\u914d\u7f6e<\/p>\n

    1\u3001\u8a3b\u91cb\u6389\u4e0d\u9700\u8981\u7684\u4f7f\u7528\u8005\u548c\u4f7f\u7528\u8005\u7d44
    2\u3001\u7d66\u4e0b\u9762\u7684\u6a94\u6848\u52a0\u4e0a\u4e0d\u53ef\u8b8a\u66f4\u5c6c\u6027\uff0c\u5f9e\u800c\u9632\u6b62\u975e\u6388\u6b0a\u4f7f\u7528\u8005\u7372\u5f97\u6b0a\u9650
    3\u3001\u4fee\u6539\/etc\/inittab\u6a94\u6848\uff0c\u5c07\u300dca::ctrlaltdel:\/sbin\/shutdown-t3-rnow\u300d\u4e00\u884c\u8a3b\u91cb\u6389\u3002
    4\u3001\u9650\u5236su\u6307\u4ee4
    5\u3001\u9632\u6b62\u653b\u64ca
    6\u3001\u9650\u5236\u4e0d\u540c\u6a94\u6848\u7684\u6b0a\u9650
<\/strong>
<\/p>\n

1\u3001\u8a3b\u91cb\u6389\u4e0d\u9700\u8981\u7684\u4f7f\u7528\u8005\u548c\u4f7f\u7528\u8005\u7d44<\/p>\n

    vi \/etc\/passwd<\/p>\n

    #adm
    #lp
    #sync
    #shutdown
    #halt
    #news
    #uucp
    #operator
    #games
    #gopher
    #ftp<\/p>\n

    vi \/etc\/group<\/p>\n

    #adm
    #lp
    #news
    #uucp
    #games
    #dip<\/p>\n

2\u3001\u7d66\u4e0b\u9762\u7684\u6a94\u6848\u52a0\u4e0a\u4e0d\u53ef\u8b8a\u66f4\u5c6c\u6027\uff0c\u5f9e\u800c\u9632\u6b62\u975e\u6388\u6b0a\u4f7f\u7528\u8005\u7372\u5f97\u6b0a\u9650<\/p>\n

    #chattr +i \/etc\/passwd
    #chattr +i \/etc\/shadow
    #chattr +i \/etc\/group
    #chattr +i \/etc\/gshadow<\/p>\n

\u6b0a\u9650\u4fee\u6539\u4e4b\u5f8c\uff0c\u5c31\u7121\u6cd5\u52a0\u5165\u522a\u9664\u4f7f\u7528\u8005\u4e86\u3002\u8981\u53d6\u6d88\u4e4b\u524d\u7684\u4fee\u6539\uff0c<\/p>\n

    #lsattr \/etc\/passwd \/etc\/shadow \/etc\/group \/etc\/gshadow<\/p>\n

lsattr \u53ea\u662f\u986f\u793a\u6a94\u6848\u7684\u5c6c\u6027<\/p>\n

    #chattr -i \/etc\/passwd
    #chattr -i \/etc\/shadow
    #chattr -i \/etc\/group
    #chattr -i \/etc\/gshadow<\/p>\n

\u518d\u6b21\u6aa2\u8996
lsattr \/etc\/passwd \/etc\/shadow \/etc\/group \/etc\/gshadow
————- \/etc\/passwd
————- \/etc\/shadow
————- \/etc\/group
————- \/etc\/gshadow
\u4fee\u6539\u5b8c\u4e4b\u5f8c\uff0c\u518d\u57f7\u884c<\/p>\n

    chattr +i \/etc\/passwd
    chattr +i\/etc\/shadow
    chattr +i \/etc\/group
    chattr +i\/etc\/gshadow<\/p>\n

\u7981\u6b62Ctrl+Alt+Delete\u91cd\u65b0\u555f\u52d5\u6a5f\u5668\u6307\u4ee4
3\u3001\u4fee\u6539\/etc\/inittab\u6a94\u6848\uff0c\u5c07\u300dca::ctrlaltdel:\/sbin\/shutdown-t3-rnow\u300d\u4e00\u884c\u8a3b\u91cb\u6389\u3002<\/p>\n

\u7136\u5f8c\u91cd\u65b0\u8a2d\u5b9a\/etc\/rc.d\/init.d\/\u76ee\u9304\u4e0b\u6240\u6709\u6a94\u6848\u7684\u8a31\u53ef\u6b0a\u9650\uff0c\u904b\u884c\u5982\u4e0b\u6307\u4ee4\uff1a<\/p>\n

    # chmod -R 700 \/etc\/rc.d\/init.d\/*<\/p>\n

\u9019\u6a23\u4fbf\u50c5\u6709root\u53ef\u4ee5\u8b80\u3001\u5beb\u6216\u57f7\u884c\u4e0a\u8ff0\u6240\u6709\u8173\u672c\u6a94\u6848\u3002
4\u3001\u9650\u5236su\u6307\u4ee4<\/p>\n

\u7576\u4e0d\u60f3\u4efb\u4f55\u4eba\u80fd\u5920su\u4f5c\u70baroot\uff0c\u53ef\u4ee5\u7de8\u8f2f\/etc\/pam.d\/su\u6a94\u6848\uff0c\u589e\u52a0\u5982\u4e0b\u5169\u884c\uff1a<\/p>\n

    auth sufficient \/lib\/security\/pam_rootok.sodebug
    auth required \/lib\/security\/pam_wheel.sogroup=isd<\/p>\n

\u9019\u6642\uff0c\u50c5isd\u7d44\u7684\u4f7f\u7528\u8005\u53ef\u4ee5su\u4f5c\u70baroot\u3002\u6b64\u5f8c\uff0c\u5982\u679c\u5e0c\u671b\u4f7f\u7528\u8005admin\u80fd\u5920su\u4f5c\u70baroot\uff0c\u53ef\u4ee5\u904b\u884c\u5982\u4e0b\u6307\u4ee4\uff1a<\/p>\n

    #usermod -G 10 admin<\/p>\n

5\u3001\u9632\u6b62\u653b\u64ca<\/p>\n

1\uff09\u963b\u6b62ping, \u62b5\u79a6SYN:
\u5982\u679c\u6c92\u4eba\u80fdping\u901a\u7cfb\u7d71\uff0c\u5b89\u5168\u6027\u81ea\u7136\u589e\u52a0\u4e86\uff0c\u70ba\u6b64\uff0c\u6211\u5011\u53ef\u4ee5\u5728\/etc\/rc.d\/rc.local\u6a94\u6848\u4e2d\u589e\u52a0\u5982\u4e0b\u4e00\u884c<\/p>\n

    echo 1>\/proc\/sys\/net\/ipv4\/icmp_echo_ignore_all<\/p>\n

SYN\u653b\u64ca\u662f\u5229\u7528TCP\/IP\u5354\u5b9a3\u6b21\u63e1\u624b\u7684\u539f\u7406\uff0c\u50b3\u9001\u5927\u91cf\u7684\u5efa\u7acb\u9023\u7dda\u7684\u7db2\u8def\u5305\uff0c\u4f46\u4e0d\u5be6\u969b\u5efa\u7acb\u9023\u7dda\uff0c\u6700\u7d42\u5c0e\u81f4\u88ab\u653b\u64ca\u4f3a\u670d\u5668\u7684\u7db2\u8def\u4f47\u5217\u88ab\u4f54\u6eff\uff0c\u7121\u6cd5\u88ab\u6a19\u6e96\u4f7f\u7528\u8005\u8a2a\u554f\u3002
Linux\u5167\u6838\u63d0\u4f9b\u4e86\u82e5\u5e72SYN\u95dc\u806f\u7684\u914d\u7f6e\uff0c\u7528\u6307\u4ee4\uff1a<\/p>\n

    sysctl -a | grep syn<\/p>\n

\u770b\u5230\uff1a
net.ipv4.tcp_max_syn_backlog = 1024
net.ipv4.tcp_syncookies = 0
net.ipv4.tcp_synack_retries = 5
net.ipv4.tcp_syn_retries = 5
tcp_max_syn_backlog\u662fSYN\u4f47\u5217\u7684\u9577\u5ea6\uff0ctcp_syncookies\u662f\u4e00\u500b\u958b\u95dc\uff0c\u662f\u5426\u958b\u555fSYN Cookie\u529f\u80fd\uff0c\u8a72\u529f\u80fd\u53ef\u4ee5\u9632\u6b62\u90e8\u5206SYN\u653b\u64ca\u3002tcp_synack_retries\u548ctcp_syn_retries\u5b9a\u7fa9SYN\u7684\u91cd\u8a66\u6b21\u6578\u3002
\u52a0\u5927SYN\u4f47\u5217\u9577\u5ea6\u53ef\u4ee5\u5bb9\u7d0d\u66f4\u591a\u7b49\u5f85\u9023\u7dda\u7684\u7db2\u8def\u9023\u7dda\u6578\uff0c\u958b\u555fSYN Cookie\u529f\u80fd\u53ef\u4ee5\u963b\u6b62\u90e8\u5206SYN\u653b\u64ca\uff0c\u964d\u4f4e\u91cd\u8a66\u6b21\u6578\u4e5f\u6709\u4e00\u5b9a\u6548\u679c\u3002
\u8abf\u6574\u4e0a\u8ff0\u8a2d\u5b9a\u7684\u65b9\u6cd5\u662f\uff1a
vi \/etc\/rc.d\/rc.local ,\u5c07\u4e0b\u9762\u7684\u6307\u4ee4\u6cd5\u52a0\u5165\u9032\u53bb<\/p>\n

    sysctl -w net.ipv4.tcp_max_syn_backlog=2048 #\u589e\u52a0SYN\u4f47\u5217\u9577\u5ea6\u52302048
    sysctl -w net.ipv4.tcp_syncookies=1 #\u958b\u555fSYN COOKIE\u529f\u80fd
    sysctl -w net.ipv4.tcp_synack_retries=3 #\u964d\u4f4e\u91cd\u8a66\u6b21\u6578
    sysctl -w net.ipv4.tcp_syn_retries=3<\/p>\n

2\uff09\u9632\u6b62IP\u6b3a\u9a19
\u7de8\u8f2fhost.conf\u6a94\u6848\u4e26\u589e\u52a0\u5982\u4e0b\u5e7e\u884c\u4f86\u9632\u6b62IP\u6b3a\u9a19\u653b\u64ca\u3002<\/p>\n

    order hosts,bind #\u540d\u7a31\u89e3\u91cb\u9806\u5e8f
    multi on #\u5bb9\u8a31\u4e3b\u6a5f\u64c1\u6709\u591a\u500bIP\u4f4d\u5740
    nospoof on #\u7981\u6b62IP\u4f4d\u5740\u6b3a\u9a19<\/p>\n

3\uff09\u9632\u6b62DoS\u653b\u64ca
\u5c0d\u7cfb\u7d71\u6240\u6709\u7684\u4f7f\u7528\u8005\u8a2d\u5b9a\u8cc7\u6e90\u9650\u5236\u53ef\u4ee5\u9632\u6b62DoS\u985e\u578b\u653b\u64ca\uff0c\u5982\u6700\u5927\u7a0b\u5f0f\u6578\u548c\u8a18\u61b6\u9ad4\u4f7f\u7528\u6578\u91cf\u7b49\u3002
\u4f8b\u5982\uff0c\u53ef\u4ee5\u5728\/etc\/security\/limits.conf\u4e2d\u52a0\u5165\u5982\u4e0b\u5e7e\u884c\uff1a<\/p>\n

    * hard core 0
    * hard rss 5000
    * hard nproc 20<\/p>\n

\u7136\u5f8c\u5fc5\u9808\u7de8\u8f2f\/etc\/pam.d\/login\u6a94\u6848\u6aa2\u67e5\u4e0b\u9762\u4e00\u884c\u662f\u5426\u5b58\u5728\u3002
session required \/lib\/security\/pam_limits.so
4\uff09\u4fee\u6539sshd_config\u6a94\u6848
\u9996\u5148\u4fee\u6539\u914d\u7f6e\u6a94 vi \/etc\/ssh\/sshd_config
a \u4fee\u6539SSH\u9023\u63a5\u57e0
\u627e\u5230#Port 22\u4e00\u6bb5\uff0c\u9019\u88e1\u662f\u6a19\u8b58\u9810\u8a2d\u4f7f\u752822\u9023\u63a5\u57e0\uff0c\u4fee\u6539\u70ba\u5982\u4e0b\uff1a<\/p>\n

    Port 22
    Port 50000<\/p>\n

\u7136\u5f8c\u5132\u5b58\u96e2\u958b
\u57f7\u884c\/etc\/init.d\/sshd restart
\u9019\u6a23SSH\u9023\u63a5\u57e0\u5c07\u540c\u6642\u5de5\u4f5c\u820722\u548c50000\u4e0a\u3002
\u73fe\u5728\u7de8\u8f2f\u9632\u706b\u7246\u914d\u7f6e\uff1avi \/etc\/sysconfig\/iptables
\u555f\u752850000\u9023\u63a5\u57e0\u3002
\u57f7\u884c\/etc\/init.d\/iptables restart
\u73fe\u5728\u8acb\u4f7f\u7528ssh\u5de5\u5177\u9023\u7dda50000\u9023\u63a5\u57e0\uff0c\u4f86\u6e2c\u8a66\u662f\u5426\u5b8c\u6210\u3002
\u5982\u679c\u9023\u7dda\u5b8c\u6210\u4e86\uff0c\u5247\u518d\u6b21\u7de8\u8f2fsshd_config\u7684\u8a2d\u5b9a\uff0c\u5c07\u88e1\u908a\u7684Port22\u522a\u9664\uff0c\u5373\u53ef\u3002
b \u53ea\u4f7f\u7528SSH v2
\u5c07#Protocol 2,1\u6539\u70ba Protocol 2
c \u9650\u5236\u4f7f\u7528\u8005\u7684SSH\u8a2a\u554f
\u5047\u8a2d\u6211\u5011\u53ea\u8981root\uff0cvivek\u548cjerry\u4f7f\u7528\u8005\u80fd\u901a\u904eSSH\u4f7f\u7528\u7cfb\u7d71\uff0c\u5411sshd_config\u914d\u7f6e\u6a94\u4e2d\u52a0\u5165\uff1a<\/p>\n

    AllowUsers root vivek jerry<\/p>\n

d \u914d\u7f6e\u9592\u7f6e\u903e\u6642\u96e2\u958b\u6642\u9593\u9593\u9694
\u4f7f\u7528\u8005\u53ef\u4ee5\u901a\u904essh\u767b\u5165\u5230\u4f3a\u670d\u5668\uff0c\u4f60\u53ef\u4ee5\u8a2d\u5b9a\u4e00\u500b\u9592\u7f6e\u903e\u6642\u6642\u9593\u9593\u9694\u907f\u514d\u51fa\u73fe\u5b64\u5152ssh\u6703\u8a71\uff0c\u958b\u555fsshd_config\u914d\u7f6e\u6a94\uff0c\u78ba\u4fdd\u6709\u5982\u4e0b\u7684\u914d\u7f6e\u9805\uff1a<\/p>\n

    ClientAliveInterval 300
    ClientAliveCountMax 0<\/p>\n

\u4e0a\u9762\u7684\u4f8b\u5b50\u8a2d\u5b9a\u7684\u9592\u7f6e\u903e\u6642\u6642\u9593\u9593\u9694\u662f300\u79d2\uff0c\u53735\u5206\u9418\uff0c\u904e\u4e86\u9019\u500b\u6642\u9593\u5f8c\uff0c\u9592\u7f6e\u4f7f\u7528\u8005\u5c07\u88ab\u81ea\u52d5\u8e22\u51fa\u51fa\u53bb\uff08\u53ef\u4ee5\u7406\u89e3\u70ba\u96e2\u958b\u767b\u5165\/\u8a3b\u92b7\uff09\u3002
e \u7981\u7528.rhosts\u6a94\u6848
\u4e0d\u8981\u8b80\u53d6\u4f7f\u7528\u8005\u7684~\/.rhosts\u548c~\/.shosts\u6a94\u6848\uff0c\u4f7f\u7528\u4e0b\u9762\u7684\u8a2d\u5b9a\u66f4\u65b0sshd_config\u914d\u7f6e\u6a94\uff1a
IgnoreRhosts yes
SSH\u53ef\u4ee5\u6a21\u64ec\u904e\u6642\u7684rsh\u6307\u4ee4\u7684\u884c\u70ba\uff0crsh\u88ab\u516c\u8a8d\u70ba\u662f\u4e0d\u5b89\u5168\u7684\u9060\u7aef\u8a2a\u554f\u5354\u5b9a\uff0c\u56e0\u6b64\u5fc5\u9808\u5f97\u7981\u7528\u6389\u3002
6\u3001\u9650\u5236\u4e0d\u540c\u6a94\u6848\u7684\u6b0a\u9650<\/p>\n

    [root@localhost ~]# chmod 700 \/usr\/bin\/
    [root@localhost ~]# chmod 750 \/usr\/bin\/*++*
    [root@localhost ~]# chmod 750 \/usr\/bin\/c++*
    [root@localhost ~]# chmod 750 \/usr\/bin\/ld
    [root@localhost ~]# chmod 750 \/usr\/bin\/as
    [root@localhost ~]# locate sqlaccess
    \/opt\/lampp\/bin\/mysqlaccess
    [root@localhost ~]# chmod 755 \/opt\/lampp\/bin\/mysqlaccess
    [root@localhost ~]# chattr +a .bash_history
    [root@localhost ~]# chattr +i .bash_history
    [root@localhost ~]# chmod 700 \/bin\/ping
    [root@localhost ~]# chmod 700 \/usr\/bin\/finger
    [root@localhost ~]# chmod 700 \/usr\/bin\/who
    [root@localhost ~]# chmod 700 \/usr\/bin\/w
    [root@localhost ~]# chmod 700 \/usr\/bin\/locate
    [root@localhost ~]# chmod 700 \/usr\/bin\/whereis
    [root@localhost ~]# chmod 700 \/usr\/bin\/vim
    [root@localhost ~]# chmod 700 \/usr\/bin\/make
    [root@localhost ~]# chmod 700 \/bin\/netstat
    [root@localhost ~]# chmod 700 \/usr\/bin\/tail
    [root@localhost ~]# chmod 700 \/usr\/bin\/less
    [root@localhost ~]# chmod 700 \/usr\/bin\/head
    [root@localhost ~]# chmod 700 \/bin\/cat
    [root@localhost ~]# chmod 700 \/bin\/uname
    [root@localhost ~]# chmod 500 \/bin\/ps
    [root@localhost ~]# chmod 500 \/usr\/sbin\/lsof<\/p>\n

<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

CentOS 5.5 \u7cfb\u7d71\u5b89\u5168\u914d\u7f6e     1\u3001\u8a3b\u91cb\u6389\u4e0d\u9700\u8981\u7684\u4f7f\u7528\u8005\u548c\u4f7f\u7528\u8005\u7d44 […]<\/p>\n","protected":false},"author":1,"featured_media":503,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[20],"class_list":["post-92","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-linux","tag-linux"],"_links":{"self":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/posts\/92"}],"collection":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/comments?post=92"}],"version-history":[{"count":0,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/posts\/92\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/media\/503"}],"wp:attachment":[{"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/media?parent=92"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/categories?post=92"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/por.tw\/linux\/wp-json\/wp\/v2\/tags?post=92"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}