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January 6, 2020 – 12:38 am

I have a squid proxy server that uses a long list of authenticated cache peers in a round-robin configuration. The process looks something like this:

The key to getting this setup working well is to weed …

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Articles in Security

Bulk-Adding IPTables Rules

December 12, 2019 – 9:46 pm

I’ve been using my mod of this handy script to block countries with iptables. One issue with the script is that it is adding rules one-by-one using the iptables -A syntax. This is the proper …

Windows 10 Upgrades

December 6, 2019 – 9:44 pm

I did the only sensible thing and disabled automatic updates on my two Windows 10 laptops. Microsoft’s belated foray into the world of CI/CD for releasing Windows patches suffers from limited automated testing.

Working with iptables Logging

November 30, 2019 – 9:41 pm

Most commonly iptables is used to allow, block, or redirect connections. However, it also has a logging feature that can be very useful for network traffic analysis and system security.

Copying File Attributes Across Servers

November 29, 2019 – 9:40 pm

To make long story short, had to fix someone’s chmod -R 777 /. A late-night copy-paste fail, it would seem. Needless to say, console access is required, as SSH will not work with permissions on …

Copying Data in a Restricted Environment

August 17, 2019 – 8:04 pm

Consider this not-so-hypothetical scenario: you have some data on server_a that you would like to copy to server_b. Unfortunately, these two servers cannot communicate with each other. Nor do they have access to any common …

Sending Windows Logs to Remote Syslog

July 6, 2019 – 11:21 am

Nothing fancy here: just a quick note on directing Windows event logs and select application logs to a remote syslog server.

Plugging iPhone’s Privacy

July 3, 2019 – 11:19 am

Many recent publications , , suggest the iPhone is full of security holes threatening your privacy. The threat seems to be coming not so much from the phone’s operating system, but from the apps, …

Finding Passwords in Logs and Shell History

June 27, 2019 – 11:15 am

Sooner or later it will happen: you type something after which you expect a password prompt then, without looking, you type the password. However, you fat-fingered the first command, and your password ended up in …

Anatomy of Internet Bullshit

June 25, 2019 – 11:12 am

Here’s an oldie from two years ago that reared its ugly head on Pocket: Starting Your Day on the Internet Is Damaging Your Brain, by Srinivas Rao. The author presents his personal opinion that reading …

Creating a Chroot Jail for SSH Access

April 17, 2019 – 4:51 pm

Just a quick collection of notes on – rather than a definitive guide to – setting up an SSH chroot jail on RHEL 6. The same should work on RHEL 7 and unrelated flavors. For …

The Unix Oriental

April 14, 2019 – 4:16 pm

Placed quite appropriately in the “Security” category – my favorite Oriental cocktail recipe. Distinguishing it from the classic preparation, are absence of sweet vermouth and lime juice, as well as addition of just a couple …

Encrypting Log Data During Log Rotation

April 9, 2019 – 4:12 pm

Most log files do not contain personally-identifiable information or other sensitive data. And even if they do, encryption of all personal data is not mandatory under GDPR. Still, on occasion, for testing and troubleshooting purposes …

Late Night Rant: Facebook

March 25, 2019 – 4:15 pm

According to media reports, since 2012, millions of Facebook and Instagram logins and plaintext passwords have been sitting on some internal Facebook system, accessible by  thousands of the company’s employees.

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
vault safe

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 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
Computer Password Security

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 …