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check open ports without netstat or lsof

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Port Knocking!
Knock on ports to open a port to a service (ssh for example) and knock again to close the port. You have to install knockd. See example config file below. [options] logfile = /var/log/knockd.log [openSSH] sequence = 3000,4000,5000 seq_timeout = 5 command = /sbin/iptables -A INPUT -i eth0 -s %IP% -p tcp --dport 22 -j ACCEPT tcpflags = syn [closeSSH] sequence = 5000,4000,3000 seq_timeout = 5 command = /sbin/iptables -D INPUT -i eth0 -s %IP% -p tcp --dport 22 -j ACCEPT tcpflags = syn

Use a regex as a field separator awk

Add temporary entry to authorized_keys
If you frequently need to connect to your ubersecure mainframe from various uberunsafe machines, you have to face difficult decision: (a) type the password everytime during the session (lame), (b) add local public key to mainframes authorized_keys file (unsafe), (c) as above, but remove this key at the end of the session (pain in the a55). So let's say you save The Command to tempauth file in bin directory of your mainframe's account and make it executable. Then, while you're on one of these unsafe ones, do: $ cat $HOME/.ssh/id_rsa.pub|ssh 5z474n@mainframe.nl bin/tempauth 30 and password prompts stop the harassment for 30 minutes and you don't have to care to remove the unsafe key after that.

list files recursively by size

recursive search and replace old with new string, inside files
This command find all files in the current dir and subdirs, and replace all occurances of "oldstring" in every file with "newstring".

Upload images to omploader.org from the command line.
This function uploads images to http://omploader.org and then prints out the links to the file. Some coloring can also be added to the command with: $ompload() { curl -F file1=@"$1" http://omploader.org/upload|awk '/Info:|File:|Thumbnail:|BBCode:/{gsub(/

list files recursively by size

check open ports without netstat or lsof


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