masscan

MASSCAN: Mass IP port scanner This is an Internet-scale port scanner. It can scan the entire Internet in under 5 minutes, transmitting 10 million packets per second, from a single machine. Its usage (parameters, output) is similar to nmap, the most famous port scanner. When in doubt, try one of those features -- features that support widespread scanning of many machines are supported, while in-depth scanning of single machines aren't. Internally, it uses asynchronous transmission, similar to port scanners like scanrand, unicornscan, and ZMap. It's more flexible, allowing arbitrary port and address ranges. NOTE: masscan uses its own ad hoc TCP/IP stack. Anything other than simple port scans may cause conflict with the local TCP/IP stack. This means you need to use either the --src-ip option to run from a different IP address, or use --src-port to configure which source ports masscan uses, then also configure the internal firewall (like pf or iptables) to firewall those ports from the rest of the operating system. This tool is free, but consider contributing money to its development: Bitcoin wallet address: 1MASSCANaHUiyTtR3bJ2sLGuMw5kDBaj4T Building On Debian/Ubuntu, it goes something like the following. It doesn't really have any dependencies other than a C compiler (such as gcc or clang). sudo apt-get --assume-yes install git make gcc git clone https://github.com/robertdavidgraham/masscan cd masscan make This puts the program in the masscan/bin subdirectory. To install it (on Linux) run: make install The source consists of a lot of small files, so building goes a lot faster by using the multi-threaded build. This requires more than 2gigs on a Raspberry Pi (and breaks), so you might use a smaller number, like -j4 rather than all possible threads. make -j While Linux is the primary target platform, the code runs well on many other systems (Windows, macOS, etc.). Here's some additional build info: Windows w/ Visual Studio: use the VS10 project Windows w/ MinGW: just type make Windows w/ cygwin: won't work Mac OS X /w XCode: use the XCode4 project Mac OS X /w cmdline: just type make FreeBSD: type gmake other: try just compiling all the files together, cc src/*.c -o bin/masscan On macOS, the x86 binaries seem to work just as fast under ARM emulation. Usage Usage is similar to nmap. To scan a network segment for some ports: # masscan -p80,8000-8100 10.0.0.0/8 2603:3001:2d00:da00::/112 This will: scan the 10.x.x.x subnet, and 2603:3001:2d00:da00::x subnets scans port 80 and the range 8000 to 8100, or 102 ports total, on both subnets print output to <stdout> that can be redirected to a file To see the complete list of options, use the --echo feature. This dumps the current configuration and exits. This output can be used as input back into the program: # masscan -p80,8000-8100 10.0.0.0/8 2603:3001:2d00:da00::/112 --echo > xxx.conf # masscan -c xxx.conf --rate 1000 Banner checking Masscan can do more than just detect whether ports are open. It can also complete the TCP connection and interaction with the application at that port in order to grab simple "banner" information. Masscan supports banner checking on the following protocols: FTP HTTP IMAP4 memcached POP3 SMTP SSH SSL SMBv1 SMBv2 Telnet RDP VNC The problem with this is that masscan contains its own TCP/IP stack separate from the system you run it on. When the local system receives a SYN-ACK from the probed target, it responds with a RST packet that kills the connection before masscan can grab the banner. The easiest way to prevent this is to assign masscan a separate IP address. This would look like one of the following examples: # masscan 10.0.0.0/8 -p80 --banners --source-ip 192.168.1.200 # masscan 2a00:1450:4007:810::/112 -p80 --banners --source-ip 2603:3001:2d00:da00:91d7:b54:b498:859d The address you choose has to be on the local subnet and not otherwise be used by another system. Masscan will warn you that you've made a mistake, but you might've messed up the other machine's communications for several minutes, so be careful. In some cases, such as WiFi, this isn't possible. In those cases, you can firewall the port that masscan uses. This prevents the local TCP/IP stack from seeing the packet, but masscan still sees it since it bypasses the local stack. For Linux, this would look like: # iptables -A INPUT -p tcp --dport 61000 -j DROP # masscan 10.0.0.0/8 -p80 --banners --source-port 61000 You probably want to pick ports that don't conflict with ports Linux might otherwise choose for source-ports. You can see the range Linux uses, and reconfigure that range, by looking in the file: /proc/sys/net/ipv4/ip_local_port_range On the latest version of Kali Linux (2018-August), that range is 32768 to 60999, so you should choose ports either below 32768 or 61000 and above. Setting an iptables rule only lasts until the next reboot. You need to lookup how to save the configuration depending upon your distro, such as using iptables-save and/or iptables-persistent. On Mac OS X and BSD, there are similar steps. To find out the ranges to avoid, use a command like the following: # sysctl net.inet.ip.portrange.first net.inet.ip.portrange.last On FreeBSD and older MacOS, use an ipfw command: # sudo ipfw add 1 deny tcp from any to any 40000 in # masscan 10.0.0.0/8 -p80 --banners --source-port 40000 On newer MacOS and OpenBSD, use the pf packet-filter utility. Edit the file /etc/pf.conf to add a line like the following: block in proto tcp from any to any port 40000:40015 Then to enable the firewall, run the command: # pfctl -E If the firewall is already running, then either reboot or reload the rules with the following command: # pfctl -f /etc/pf.conf Windows doesn't respond with RST packets, so neither of these techniques are necessary. However, masscan is still designed to work best using its own IP address, so you should run that way when possible, even when it is not strictly necessary. The same thing is needed for othe