This is a very generic PHP reverse shell. It’s possible you know you have a linux type OS, but what if bash is in /usr/bin/ instead of /bin/? Do some recon, know what you’re working with, and, if you really have every reason to believe you should be getting a shell but you aren’t, always assume you’ve done something wrong. Each one of these can be adjusted and may need to be. You shouldn’t be trying to get a shell back unless you have a good idea of what the underlying OS is. Something like remotephone_j1er234.php is harder to brute force and way easier to track down for cleanup. Use a complex naming schema that can’t be brute forced or ideally a tag that can be found repeatedly. Relatedly, if you’re uploading a file to an externally available site like a web shell, don’t name it admin.php or shell.php. Use reverse shells, encrypt when possible, and clean up after yourself. If someone is already inside the client’s network, you’ve just made their job that much easier when your goal is the opposite.
Netcat reverse shell task lab windows#
If you’re part of a real engagement for a customer or doing something in house, you can’t leave bind shells everywhere, it’s like leaving windows open for burglars. If you can bind to the port, anyone else can. Bind shells are great, but they’re irresponsible. But bind shells are easier!Īnd therein lies the problem. You could specify port 443 only, but this wouldn’t catch if you did something wrong in your exploit and are sending the exploit back to the wrong port (we all make mistakes). In this case, since I’m attacking port 80, I’m probably listening on port 443 with a netcat listener. That watches traffic for anything coming back and gives you a condensed, simple output for it only on the interface you expect the attack to copme back through (tap0 if you’re on a VPN, for example), listening only for the victim host so you don’t see a bunch of other noise and excluding the port you know you’re going to see traffic on. Tcpdump -qtpni eth0/tap0/whatever0 host and not port 80 If I’m trying to exploit a web app on port 80 to send back a remote shell, one tcpdump quickie I use is
If you think it should work and it’s not, tcpdump or wireshark your host (if you can) and see what’s coming and going. This is an excellent write up of RCE found in Facebook that had to use outbound DNS to send results back to his listening machine.
Port 80 and 443 are great, but so is DNS. If you’re going to send yourself back a reverse shell, try ports that people should expect to see. You may have been popped by someone who barely knows what they’re doing which probably also means someone way worse is already in. If you see this port active in a production environment and can’t immediately recognize why, you need to figure it out.
Netcat reverse shell task lab code#
Way too many reverse shells and exploits code the exploit to send reverse shells back to port 4444. Reverse shells are great, but you need to make sure they get to you. These are some quick and easy ones in different formats. Stolen usernames and passwords may be one of the most reliable ways to get into a system, but theres nothing like messing something up a bunch and then finally seeing that reverse shell prompt pop up. If enumeration is the bread and butter of penetration testing, reverse shells are the cheesecake.
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