Category Archives: IT Security

Filtering Spam – Part I

Judging by the contents of the emails I receive on a daily basis, I can fairly safely say that the world is full¬†with people that don’t bother to look for technical vulnerabilities to hack my computer, but simply try to … Continue reading

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Observing packets on the wire flying by

Anyone who has ever tried to install a modem or configure an Internet connection has almost certainly wondered if there’s any traffic flowing back and forth from networks. Observing network traffic that is generated by a PC or Mac is … Continue reading

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Passwords revisited

After having generated pre-shared secret keys for IPsec VPNs, as recommended by the NSA, I wondered how “secure” the keys themselves actually were. The NSA specifically mentions the use of “large, high entropy, pre-shared keys”. Quite some time ago I … Continue reading

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When a firewall fails to defend a network…

While it is true that a firewall today still is an important piece of networking equipment to logically separate different networks, its functionality has shifted over the years from plain network filtering to application level protocol inspection and intrusion prevention … Continue reading

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Javascript IPsec configuration generator for site-2-site VPN gateways

Today, access to the internet is practically everywhere. Private communication across it is often taken for granted. There is an entire industry around secure¬†communication and a lot of the equipment used for securing network boundaries, VPNs specifically, relies on the … Continue reading

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Using Elliptic Curve with an OpenSSL PKI

OpenSSL is a tool that can be used to setup a (simple) PKI, but in its most basic form a command line tool with an endless amount of options. I find myself searching for the correct syntax of OpenSSL to … Continue reading

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Tracking email using web bugs

“Did you get my email?” If you have ever asked this question to anyone, then this post might interest you. I had my doubts about sharing this, since the trick described here does invade the privacy of the recipient somewhat, … Continue reading

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Email and malware dissection, Part II

If you’re running a mail server on the Internet, you will surely be familiar with spam and malicious email. This post is the last part on how to identify and isolate malware in email while respecting your users’ email privacy. … Continue reading

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Email and malware dissection, Part I

Phishing, Trojans, Worms and other malicious activity in email. These series of posts make quite a lengthy write-up on how to use Unix shell script and Perl to dissect large amounts of email all at once without disrespecting email privacy … Continue reading

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Tinkering with file encryption

Storing files overseas or “in the cloud” has become somewhat of an issue lately with spying activities of various nations. I think we’ve just seen the top of the iceberg, but at the same time I hope I’m wrong. In … Continue reading

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