Ossi Herrala – Medium

Ossi Herrala

Published in
SensorFu

Bidirectional escape testing

Bidirectional or two-way escape testing verifies that escape from an isolated network can communicate both ways: from isolated environment…

Oct 12, 2023

Bidirectional escape testing

Oct 12, 2023

Revenge of the Whitefish

Last spring (2022–04–10) I was activating WWFF reference in a small municipality in Finland called Siikajoki. That day I only got 22 QSOs…

Oct 20, 2022

Revenge of the Whitefish

Oct 20, 2022

WWFF Ninja Activation in Hiastinlahti

Ninja Activation: Go to site, seen by nobody, have QSOs. Then leave no trace behind and vanish. Nobody knew about your activation before…

Apr 13, 2022

WWFF Ninja Activation in Hiastinlahti

Apr 13, 2022

Sunday WWFF activation

Today’s ham radio WWFF activation headed to a small municipality in Finland called Siikajoki with a population of 5024 people and…

Apr 13, 2022

Sunday WWFF activation

Apr 13, 2022

Overnight ham radio activation in Hailuoto, Finland

Our operation was in Hailuoto, a small island (200.53 km²) in the Gulf of Bothnia with a population less than thousand people. This is my…

Nov 10, 2021

Overnight ham radio activation in Hailuoto, Finland

Nov 10, 2021

Ham radio activation in Hailuoto, Finland

Our operation was in Hailuoto, a small island (200.53 km²) in the Gulf of Bothnia with a population less than thousand people. This is my…

May 10, 2021

Ham radio activation in Hailuoto, Finland

May 10, 2021

Published in
SensorFu

Internet Protocol Next Header escape

In IPv6 header it’s called “Next Header” and in IPv4 header it’s just “Protocol”. This eight bit value contains information about what…

Jan 26, 2021

Internet Protocol Next Header escape

Jan 26, 2021

Published in
SensorFu

How we turned 5G into 5k

Hacking is a good way of learning and hackathons are a great place to learn with other like minded people. And that was exactly what we…

Dec 9, 2019

How we turned 5G into 5k

Dec 9, 2019

110 m/s towards a planet!

This is a short story about a survival scenario I played in the game Space Engineers by Keen Software House. I got inspiration to play…

Jan 4, 2019

110 m/s towards a planet!

Jan 4, 2019

Published in
SensorFu

Using static typing to protect against code injection attacks

Code injection attack is a method of taking advantage of a flaw where an application can be tricked to relay malicious code from a system…

Jan 16, 2018

Using static typing to protect against code injection attacks

Jan 16, 2018

Published in
SensorFu

Continuous testing but with irregular schedule

Almost but not quite half an hour

Jan 3, 2018

Continuous testing but with irregular schedule

Jan 3, 2018

Published in
SensorFu

Special Privileges: No thanks!

Changes to network configuration can be difficult and time consuming to do. Today’s networks are virtualized, complex and outsourced to 3rd…

Dec 18, 2017

Dec 18, 2017

Published in
SensorFu

The Story about Ping

Beacon sends Pings towards Home. Ping contain just enough information (and nothing more) for Home to understand where the Ping came from…

Dec 14, 2017

The Story about Ping

Dec 14, 2017

Published in
SensorFu

SensorFu Teaser V — Launch Imminent

Trying to learn from consumer electronics twists your mind. Especially if you mind is more geared towards network hacks. We are close to…

Nov 16, 2017

SensorFu Teaser V — Launch Imminent

Nov 16, 2017

Published in
OUSPG

Xipology (3⁄3) — Rendezvous in DNS space

This is the last part in series of three blog posts talking about exploiting Domain Name System (DNS) caching as a carrier. In the first…

Oct 19, 2017

Xipology (3⁄3) — Rendezvous in DNS space

Oct 19, 2017

Published in
OUSPG

Xipology (⅔) — A library for turning DNS caching into a carrier

This is part two in series of three blog posts talking about exploiting Domain Name System (DNS) caching as a carrier. In first part we…

Oct 19, 2017

Xipology (⅔) — A library for turning DNS caching into a carrier

Oct 19, 2017

Published in
OUSPG

Xipology (⅓) — Exploiting DNS caching as a carrier

This is our story of exploiting caching Domain Name System (DNS) servers to break network segregation. We’ll call it Xipology and introduce…

Oct 19, 2017

Xipology (⅓) — Exploiting DNS caching as a carrier

Oct 19, 2017

QuickCheck or Fuzzing? Which one to use?

TL;DR: QuickCheck for fast testing of functions with random values as part of a test suite. Fuzzers (model or mutation based) take longer…

Feb 18, 2017

QuickCheck or Fuzzing? Which one to use?

Feb 18, 2017

Published in
HowNetWorks

How did I turn my Browser into a Port Scanner? Tricksy but doable

Modern web browsers are full of features. It’s possible to watch movies, listen to music, and make phone and video calls with just a few…

Jan 10, 2017

How did I turn my Browser into a Port Scanner? Tricksy but doable

Jan 10, 2017

Published in
HowNetWorks

Don’t waste cycles with modulo bias!

TL;DR Use proper function to generate uniform random values (like arc4random_uniform()) instead of fighting against modulo bias yourself.

Nov 2, 2016

Nov 2, 2016

Ossi Herrala

Ossi Herrala

Co-founder and R&D lead of @sensorfu. Interested about free software, network security, and ham radio (callsign OH8HUB).

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