The message sometimes appear when transferring files using scp.
In order to solve this, you need to edit “/etc/sshd_config” file and change or add this line:
Then restart OpenSSH server. This will solve the kex protocol error problem,
This XKCD strip explains what essentially Meltdown vulnerability which affects Intel microprocessor
Nmap (or Network Mapper) is probably the most popular network mapper around. However if you are running a very stable long-term support server, there are chances that your nmap database installation isn’t keep up to that.
Updating Nmap database
Nmap detection database consists of these files:
What you need to do is to download these files from Nmap Github project page and copy it to /usr/share/nmap/ folder.
Alternatively, you can use this script ‘nmap-update.sh’ which I’ve created based on this gist.
Copy all the files to /usr/share/nmap/ once all of them have been downloaded.
Cracking zip password can be made easy with cracker-ng
Installation is simple, assuming you use Debian, Ubuntu or any other similar operating system :
$ git clone https://github.com/BoboTiG/cracker-ng.git
$ cd cracker-ng
# For testers and contributors, always work with on the devel branch:
$ git checkout devel
Cracking is relatively simple, assuming you have downloaded the awesome Crackstation’s wordlist dictionary.
$ zipcracker-ng -f targetfile.zip -w crackstation-human-only.txt
Additionally zipcracker-ng can also be used with other brute-forcing cracking tool such as john and
$ john --incremental --stdout | zipcracker-ng -f FILE -
$ crunch 1 8 -f charset.lst lalpha | zipcracker-ng -f FILE -
Screenshot of zipcracker-ng in action
Crackstation wordlist is one of the most (if not the most) comprehensive wordlist which can be used for the purpose of dictionary -attack on passwords.
The wordlist comes in two flavors:
- Full wordlist (GZIP-compressed (level 9). 4.2 GiB compressed. 15 GiB uncompressed)
- Human-password only wordlist (GZIP-compressed. 247 MiB compressed. 684 MiB uncompressed)
Personally, I’ve already downloaded the full wordlist via torrent, and tested it against few PDF files (using pdfcrack) and UNIX password cracking (using John), all my test cases were successful. In my opinion, the wordlist is comprehensive for my need.
Since it looked like it took a significant effort to compile this wordlist, I rather advocate those who are interested to donate/buy the wordlist from: https://crackstation.net/buy-crackstation-wordlist-password-cracking-dictionary.htm
I’ve come across an PDF which was sent to my email from an automated banking system. Unfortunately, the PDF file is encrypted and I’ve no way of knowing the password (or actually I’ve forgotten the password).
Fortunately, my Ubuntu box comes with application which allows me to crack the PDF file within a reasonable time.
Using ‘pdfcrack’ to crack PDF file
You need to install pdfcrack to crack pdf file. In Ubuntu/Debian system, you simply need to run
sudo apt-get -y install pdfcrack
Then for actual cracking, you can run
pdfcrack -n5 -m10 encrypted.pdf
Where -n [minimum length] to brute-force, and -m [maximum length] to brute-force.
pdfcrack can also accept a file input containing list of words (dictionary attack). For dictionary-attack just run
pdfcrack --wordlist=dictionary.txt encrypted.pdf