Technology Insights

SSH Add Server To known_hosts Automatically

If you ever need to write a shell script that uses either SSH or SCP to unknown hosts then you will likely have run across the issue of adding the remote host/server to the known_hosts file when automating either of the two commands are called within the script. You can easily get around this either by modifying the client computers ssh_config file or by using the -o switch available for both SSH (Secure Shell) and SCP (Secure Copy). Below we show how to modify the ssh_config file as well as an example of using each with the -o switch.

Information Security

Automated Password Cracking: Use oclHashcat To Launch A Fingerprint Attack

The below article explains how I used password fingerprinting to crack 500,000 password hashes in less than half a day completly automated. This article shows each command step by step, but only to describe the details of how password fingerprinting with oclHashcat works. The reality is that the password fingerprinting process can easily be automated by a script which is why we call it automated password cracking.

The Fingerprint Attack in my example had a success rate of about 80% in a 100% automated process after 12 hours with a single GeForce GTX 285. In order to reach the 500,000 cracked hashes I first created a list of 650,000 unique password hashes using a well known leaked password hash database. Once I had the list of 650,000 unique password hashes I started out by doing some easy attacks on the hashes such as a five character long brute force using all possible character sets which will provide an initial wordlist to start the fingerprint attack with. You really do not need to perform this step as explained further below. Once the initial brute force attack is complete the real fingerprinting starts. You will take the initial results, pipe them into the expander, and then run a combined dictionary attack against the hash list. Once we have results from the second set of attacks we use the expander again and issue another attack. You will see through the process, which is described in detail below, that results are returned at a very high rate by automated finding patterns and exploiting those patterns to return results.

Technology Errors

Embassy Security Center Error: This Fingerprint Is Already Enrolled, Cannot Enroll This Fingerprint

My Dell d420 came with a biometric fingerprint scanner which is configured using the Wave Systems Embassy Security Center. If you have recently reinstalled the OS on your laptop more than likely the operating system configuration is out of sync with the TPM(Trusted Platform Module) Security Chip. This means that the biometric security will work preboot however it will not work for Windows logon. So you will not be able to swipe your fingerprint and automatically logon to Windows securely and you will also not be able to lock your computer and log back into Windows by swiping your fingerprint.