Proxychains

Proxychains

  • a useful proxifying tool that can be used with dynamic port forwarding

  • it allows us to run any network tool through HTTP, SOCKS4, and SOCKS5 proxies

Use Case:

  • Next, create a dynamic application-level port forwarding on port 8080 on our attacking machine

    • any connection made to this port will be forwarded over the SSH channel and the application protocol will be used to determine where to connect to from the remote machine

  • Lastly, configure proxychains to use port 8080 on our attacking machine

    • since the SSH process instance listening on that port will act as a SOCK server

  • Through proxychains, we can use nmap to scan the internal remote network for example

Proxychains Pivot

# When you have access to a machine, you can use it as pivot to target machines

# Getting known machines

arp -a

# Setup SSH Dynamic on the attacking box

ssh -D <local_port> <user>@<ip>

# Setup proxychains in /etc/proxychains.conf

[ProxyList]

socks4 127.0.0.1 <local_port>

# Reduce timeout in /etc/proxychains.conf to gain speed

tcp_read_time_out 800

tcp_connect_time-out 800

# Then

proxychains...

# Scanning (nmap) can be very long through proxychains

# You can speed it up by using xargs and multithreading

# The main goal is to spread ports between different threads (-P 50)

seq 1 65535 | xargs -P 50 -I port proxychains -q nmap -p port -sT -T4 10.42.42.2 -oG 10.42.42.2 --open --append-output 10.42.42.2 -Pn -n

# Take care of some options

# You can't just run -oA but need the --append-output option

# The same behavior can be used to scan multiple machines

# The base command

proxychains nmap -p- -sT -T4 --top-ports 20 10.42.42.0/24 -oG 10.42.42.0 --open

# Become

seq 1 254 | xargs -P 50 -I cpt proxychains -q nmap --top-ports 20 -sT -T4 10.42.42.cpt -oG 10.42.42.0 --open --append-output 10.42.42.cpt -Pn -n

Double Pivot Proxychains

# Pivot 1 using proxychains

ssh -D 1080 user@IP_Network1

# Configure /etc/proxychains to set port 1080

# Pivot 2 using proxychains

proxychains ssh -D 1081 user@IP_Network2

# Configure /etc/proxychains to set port 1081

proxychains nmap...

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