KrazyWorks | Category Archive

Killing Process Network Access

January 27, 2019 – 4:45 pm

Imagine this scenario: a particular process on your server is connecting to a host outside your internal network and you don’t like that. On the other hand, you can’t just kill that process because you need it.

The Facebook Fracas

January 9, 2019 – 4:48 pm

The Facebook privacy saga is getting ridiculous. You’re using a free service that you signed up for – nobody was holding a gun to your giant head. And it’s not Gulag either: just delete your profile, uninstall the damned app, and forget Facebook ever existed.

Obfuscating Shell Scripts

August 1, 2018 – 4:04 pm

Unix shell scripting language is run by the command-line interpreter and, as such, can be read and understood by anyone with sufficient access and experience. Sometimes this is not a good thing. Sometimes you want …

Encrypted Volumes and Portable Apps

February 25, 2018 – 3:08 pm

This is a description of an uncomplicated setup for an encrypted volume and portable applications for a Windows laptop consisting of a USB3 storage device, VeraCrypt OSS OTFE, a hardware password wallet, and portableapps.com software.

Detect SSL Certificate Injection

February 21, 2018 – 3:05 pm

When the SSL Digital Certificate is intercepted and replaced by a device between your browser and the Web site, we call it certificate injection. This method is more commonly used not by hackers, but by …

SSL For Self-Hosted WordPress

February 17, 2018 – 3:05 pm

Just some notes for setting up SSL with your self-hosted WordPress hosting installation. Just got around to doing this the other day. Yeah, I know, about time…

Show Logged In Users During a Time Window

February 17, 2018 – 2:59 pm

Let’s say you want to see who was logged in on the server during last weekend. This includes users who, say, logged in on Thursday and haven’t logged out until Saturday afternoon.

Increasing Entropy Pool in Linux

June 28, 2016 – 9:48 pm

The pool of random numbers in Linux is derived primarily from user interaction (keystrokes and mouse movement). A server does not have such a source and the random pool may start running low, especially during …

Using JTR to Crack Office Documents

April 22, 2016 – 5:35 pm

John the Ripper is a free multi-platform password-cracking software. This article is not intended to be a comprehensive guide to jtr, rather a quick how-to. Starting with version 1.7.9, jumbo patch 6, jtr supports password …

Securing VSFTP with TCP Wrappers and IPTables

November 11, 2015 – 1:44 am

I’ve been drinking beer and perhaps had one too many. Regardless of the reason, I felt the urge to further secure my favorite server. The target of my paranoia is once again the VSFTPd. I …

Removing Metadata from Images

September 8, 2015 – 12:09 pm

Phones and cameras record a surprising amount of personally-sensitive information with the photos they create. This data includes timestamps, GPS coordinates, software used to process the images and lots of other details you may not …

Login Monitor

March 6, 2015 – 12:02 am

Sometimes after a couple of beers I start feeling paranoid. I make sure the door is locked and check my firewall logs. Here’s a very basic script to monitor your server’s login record and notify you about …

Ad-Hoc Analysis of /var/log/secure

February 28, 2015 – 9:41 pm

The /var/log/secure contains a record of authentication and authorization activity on the system. It can be an invaluable resource for the purposes of intrusion detection and prevention. Below are a few simple examples that show how …

Late Night Rant #24: North Korean Internet

December 22, 2014 – 8:05 pm

North_Korea-Pyongyang-Computer_class_at_a_school-01

Today was the day the North Koreans would have learned they had the Internet and the Americans DDOSed it. Unfortunately, they had no Internet, poor bastards. But, as long as this keeps us entertained… Hey, …

Late Night Rant #23: Kim The Sony-Slayer

December 17, 2014 – 10:09 pm

Sony execs are shedding crocodile tears over the latest IT security breach that brought substantial financial losses to the company. Let’s not dwell on the trivial: who did it and why are irrelevant technicalities. How …

VSFTPd, SSL, and Firewalls

December 5, 2014 – 1:58 pm

If you ever wanted to configure SSL/TLS encryption for an FTP server behind a firewall, the “Google wisdom” ranges from “a major pain” to “can’t be done”. Fortunately, things are not all that bad. In …

Remove Duplicate IPTables Rules

September 24, 2014 – 6:26 pm

Duplicate entries may appear in your iptables configuration due to parallel efforts of various network security-related applications that may be running on your server. In most cases, having duplicate iptables rules is no big deal, …

Secure Data Destruction for Unix

February 21, 2013 – 11:45 pm

What is secure computer data destruction? Simply put, securely-deleted data cannot be recovered by any known technique. But when it comes to data security, things are rarely simple. New data recovery methods are developed every …

Facebook Security for the Lazy

April 28, 2011 – 2:36 am

Every time you use Facebook, you probably have a nagging feeling in the back of your head that someone other than your friends is reading your posts. You should trust that feeling. At the same time, keep in mind that Facebook is a tool designed primarily for sharing personal information with large groups of people you barely know. Facebook is not your personal diary or a substitute for SMS. You just need to assume that everything you post on Facebook inevitably will end up in the hands of someone you don’t like very much. And then you proceed based on that assumption.

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