The Java Hacker – Peter Jaric's Blog

Category: Uncategorized

7 Reasons Why You Should Become a Bug Bounty Hunter

A while back, Gregoire Gilbert and Johannes Ridderstedt (then Lundberg) of the Uppsala Tech community asked me if I could write an article about bug bounty hunting for their upcoming magazine The Uppdate. Its first issue is now available at and I’m very proud the be part of it. I recommend you to go […]

An Øredev 2015 summary – Swedish only

This is a report about Øredev 2015 that I posted on my employer’s intranet. Due to the huge demand I asked if I could publish it on the internet. Unfortunately it is available in Swedish only. I våras råkade jag hitta ett säkerhetshål på utvecklarekonferensen Øredevs webbplats. Som tack för hjälpen fick jag en gratisbiljett […]

The First JavaScript Misdirection Contest

Finally we have a winner! But first, some background. One month ago, on the 29th of August, I announced the JavaScript Misdirection Contest: There is a programming contest called The Underhanded C Contest. In their own words, it is “an annual contest to write innocent-looking C code implementing malicious behavior”. I am very much intrigued […]

Linkifying robots.txt

I find it quite fun to look for vulnerabilities in websites and then report them (to hopefully gain a bug bounty or at least a place on a Hall of Fame list). One place to find interesting stuff is in the robots.txt file present on many websites. It is quite annoying though, that the relative […]

Sea Surfer v2

A little while ago I made a bookmarklet called the Sea Surfer for detecting and exploting CSRF vulnerabilities. Since then I have got some feedback from Ashar Javed which has prompted me to create a slightly improved version. Sea Surfer v2 release notes: jQuery is loaded automatically (no need to run the jQuerify bookmarklet first) […]

Meeting Notes #1

I often draw something when I attend meetings at work. It helps me concentrate and it’s fun. I’ll upload some of these drawings here. Here’s the first one:

Citerus Programming Challenge at JFokus 2011

The company Citerus held a programming competition at the JFokus 2011 developer conference. I was one of the more than 100 contestants. Read more about it at (in Swedish). I have included both the winning solution from Carin Lidberg and my own solution below. They are quite different :) The winning solution: public class […]

Fixing a mistake in auto-opening settings in Chrome

When I was going to open a Spotify link in Google Chrome and the browser asked me if I wanted to open it or not, I checked the “Remember my decision” check box and then clicked “Do not open”, by mistake. And due to Google Chrome’s lack of customization, I could not find where to […]

Edit settings for screensavers in gnome-screensaver

In newer versions of Ubuntu (and Linuxes) xscreensaver has been replaced with gnome-screensaver. The same screensavers are supported (with some exceptions, I guess), but there is one thing that is lacking: per-screensaver configuration. The author of gnome-screensaver thinks that this is not needed. There are some ways to get around this, among them: replace gnome-screensaver […]

Playing Swedish Scrabble? Boggle?

If you’re playing Scrabble in Swedish with your friends, you will get invaluable help from my friend Jonatan‘s new web application: There you can check whether a word is valid when playing Scrabble, or just browse through words for fun. It has helped us in numerous Scrabble and Boggle games. Good gaming!