Linux Blog

Secure Encryption and Decryption of files and streams - ccrypt

ccrypt is a command line utility for encrypting and decrypting files and streams. It was designed as a replacement for the standard Unix crypt utility, which is notorious for using a very weak encryption algorithm. ccrypt is based on the Rijndael cipher, which is the U.S. government's chosen candidate for the Advanced Encryption Standard (AES). This cipher is believed to provide very strong security. A compatibility mode is included for decrypting legacy "unix crypt" files.

Unlike unix crypt, the algorithm provided by ccrypt is not symmetric, i.e., one must specify whether to encrypt or decrypt. The most common way to invoke ccrypt is via the commands ccencrypt and ccdecrypt. There is also a ccat command for decrypting a file directly to the terminal, thus reducing the likelihood of leaving temporary plaintext files around. In addition, there is a compatibility mode for decrypting legacy unix crypt files. An emacs mode is also supplied for editing encrypted text files.

Protect SSH server from dictionary attacks using iptables

iptables is built on top of netfilter, iptables is the packet alteration framework for Linux 2.4.x and 2.6.x. It is a major rewrite of its predecessor ipchains, and is used to control packet filtering, Network Address Translation (masquerading, portforwarding, transparent proxying), and special effects such as packet mangling.

If you are using SSH then you will sooner or later notice someone trying to hack into your box using dictionary attacks. You can use the iptables module recent to limit a minimum time between new connections from the same IP.

UI Application for Image Batch Processing - Phatch

Phatch is a simple to use cross-platform GUI Image Batch Processor which handles all popular image formats and can duplicate (sub) folder hierarchies. Phatch can batch resize, rotate, apply perspective, shadows, rounded corners, ... and more in minutes instead of hours or days if you do it manually. Phatch allows you to use EXIF and IPTC tags for renaming and data stamping. Phatch also supports a console version to batch photos on webservers.

Checks existence of open proxy - proxycheck

Open proxies of various kinds are used nowadays for various evil things like sending mass spam, hacking into your machine, making denial of service attacks (DoS) and the like. Every such machine should be either secured properly or turned off permanently, but that's not an option, since in most cases there is either no administrator of such machines exists at all, or he has no clue about what's on that machine, or it's irrelevant for him. So the only way to stop massive abuse made via such machines is to block them. Also, network administrators (of an ISP for example) are able to warn their clients whenever they are running an insecure proxy services - periodical scanning of client's network may also be a good idea.

This command-line tool, proxycheck, may be used for such purpose. Currently, it understands 3 types of proxy servers: HTTP proxies that allows you to CONNECT to any host:port, SOCKS v4 and v5 proxies, wingate "telnet" proxy servers of various kinds (incl. e.g. CCProxy variants and others), and FTP proxies that are able to create transparent connections.

Test your hacking skills - WackoPicko

WackoPicko is a website that contains known vulnerabilities. It was first used for the paper Why Johnny Can't Pentest: An Analysis of back-box Web Vulnerability Scanners found:
http://cs.ucsb.edu/~adoupe/static/black-box-scanners-dimva2010.pdf

WackoPicko Install Instructions:
Import the WackoPicko database into MySQL using a command like the following:

mysql -u <user> -p < current.sql

This will create the MySQL user wackopicko with the password webvuln!@# as well as create the wackopicko table. The wackopicko table contains all of the data that was present while testing the scanners in Why Johnny Can't Pentest.