Encrypt a File on Linux Using OpenSSL

December 30th, 2013

LockIt is possible to encrypt a file for secure transmission or backup using a strong cryptographic algorithm on Linux. We do that using OpenSSL:

Simple SSH Web Proxy

October 18th, 2013

It is very easy to create a simple proxy via an SSH connection to a remote server. Here’s how you do it:


Preventing Multiple Instances of a Script From Running Using flock

August 26th, 2013

Linux command line programSometimes you want to limit a script to just one instance. Say the script accesses a resource that you don’t want to be shared. So how do you prevent multiple instances of a single script from running?

Finding Number of Unique IP Addresses Involved in an Attack

August 8th, 2013

Linux command line programWeb servers sometimes get lots of requests from bots looking to exploit security holes. For example previously I have written about brute force WordPress login attempts. Attacks like these can involve thousands of IP addresses and how you block the attack depends on how many unique IPs are involved and the frequency with which they are used. Here’s how you can find out.

Faysal Bank Introduces Dangerously Insecure Internet Banking

July 23rd, 2013

Faysal Bank was probably the only private bank in Pakistan to not offer Internet banking. They were sitting on their hands all these years while their competitors leapt forward. But now they’ve introduced mobile phone compatible Internet banking under the mobit brand name. The problem is that it is badly designed and dangerously insecure.