This space is dedicated to the memory of FX.
I met FX at Feb 15 Offensive Con 2020 (right before Covid) His enthusiasm for computer hacking was phenomenal. For an hour I stood just to listen to him. I will never forget that I met a real veteran of computer hacking.
I fondly think of him quite often whenever I use the phrase "you cannot argue with a root shell".
The few times I met him, he made such an impression that I wanted to be as cool a hacker as he was.
I will remember FX as a very openminded person. You could basically come with every idea to him, and he would discuss the idea with you, making it better, rather than ditching you off or making fun of your idea. Thx man, Cheers. Zes
I came to my first CCC in 2010, with fbz and SkyTee hosting me. It was a wonderful introduction to the international hacker crew. Everyone took wonderful care of me. And this also meant meeting fx at Berlinsides, and he immediately became my quintessential “hacker” icon. Like.. I had always known that I got on well with infosec people, but fx just.. exuded it. We never became fast friends. I never had dinner at his house. But we would see each other when I would come to Berlin, and he always had time for an in-depth conversation with me. The beat of his heart became my beat as well, in a way. The way he carried this deep seated, visceral distain for any wall put between people, and an absolute commitment to getting past it, resonated so hard with me that it became my guidance. So he had an outsized impact on me, one for which I’m deeply grateful.
I will also forever remember him inviting me to a “little party” he was putting on, that ended up being a multi-floor rager in an old railway building of some kind, and finding him there smoking a cigarette and teasing him about how little his party was. His smile and laugh were so warmly given. So to me, he’ll always be Berlin, and will always be hacking, and I’m sad to no longer have the living embodiment of these beautiful ideas.
Riley E
The greatest fun I have ever had was at pH-Neutral during the silo party, walking down the ramps and talking with him. Here was one of the brightest minds in the security world, at the center of attention and known by everyone, yet all he wanted to do was ask about what I liked and what fun we should have.
His passion was so intense that it pervaded rooms, conferences, and mailing lists; his voice truly was the tide that rose all of our boats. I hope he received even a fraction of the love that the world, and I, held for him.
"You can't argue with a root shell." -- FX
This is every security researcher's favorite quote. Mine too, one I've carried with me for as long as I can remember, reaching for it every time I needed to introduce an exploit.
Among FX's countless contributions to the field of offensive security, what stays with me the most when I think about him is his work on BlackBerry, and the generosity he showed when I was approaching this subject for the first time. He eagerly shared notes, techniques, and time.
To another exceptional hacker who has left us far too soon: thank you for showing us the way.
-- raptor
The year was 1998. First Chaos Communication Congress in Haus am Köllnischen Park, Berlin. I had just read and digested Smashing the Stack by Aleph One, and now I was on stage, explaining the concepts.
In the audience, a young man was listening very carefully. It wouldn't take long for him to master this technique, soon he would surpass me, becoming one of the legends in the field. There was a vuln, but ASCII to Unicode conversion would turn every second byte of your shellcode into 0x00? He did it.
But it wasn't just his mastery of IDA, it was also his skill to bring together people. PH-Neutral was known for the parties, but its real secret was bringing the right people into one place to share stories. The list of outstanding people I've met through him is endless.
We were friends, occasional colleagues, on stage together, and ultimately sharing the same hacker spirit. Hearing of his health problems in 2017 came as a shock, and I was glad to see him recovere ever so slowly, regaining his memory of our shenanigans bit by bit. I am devastated to hear that he lost this fight.
Sit tibi terra levis, my dear old friend. You will be missed. 🕯️
I've known FX since his talk at 20c3 where I got introduced into the world of chaos as I attended my first CCC. After his talk, I chatted with him and met him over beers at one of the parties. I remember this as a transformative moment that later pushed me to stay curious and do a PhD in software/system security as this was where all the shit was at.
I was always impressed by his work but most by his Blitzableiter talk at DefCon 18; I remember being in the front row and, again at the after party, talking to him about mitigations and defenses which later shaped my PhD topic. He was an amazing open and curious person and his style will be missed.
My friendship with FX started just like I imagine many others did: random, but impactful.
After arriving in Wuxi for what ended up becoming a life-changing experience for me, all speakers had decided to meet at the hotel bar. You, already an icon in the infosec and hacker community, and I, a random noob from Belgium who ended up as a speaker by happenstance, were the first people present. I felt starstruck but mustered up enough confidence to greet you. The energy you returned was powerful and I have remembered that moment forever. You were a rockstar only by the label attributed to you. Underneath you were deeply human, interested in everything we discussed, and more than anything dedicated to sharing yourself with others. You valued the time people decided to spend with you so much, and showed it. Thanks to you, in that moment, I felt that I belonged.
There is no doubt that in Wuxi, partially because of the circumstances and partially because of who we were, we became friends. Not by other people’s definitions, but by our own. It was the start of a relationship that meandered through time and space, and that reshaped how I looked at the world, our shared passion, and life.
Over the years, in real life and online, there were a host of topics we’d discuss. None of them shallow. Because a conversation with you was always deep. While it may have started out with jokes and some banter, there was always a time where things got serious and we’d ponder about life together. I remember fondly how you spoke about your company, Recurity Labs, and more specifically the people you worked with there. You were not just hellbent on putting the best team together. You wanted Recurity Labs to be a brand that, if your people ever decided to go work somewhere else, meant enough so they would get hired. It clearly showed how you put (other) people first. Always and everywhere.
At some point you shared a song that you made together with DJ Vela. It was called “REPNE MOVSB” and had the amazing lyrics:
Repeat not equal
Move string
Bytewise
Can actually
Change the world
I don’t think you ever fully explained its meaning to me but today it is clear as day. In the face of inequality, what we can do is speak up and, with that, change the world. It is what you did on global stages, in dark and moody bars, and sometimes just sitting on a bench in the street with a kebab in our hands. And with you as an example forever in our hearts, it is now our responsibility to keep it going.
So many memories. So many good times. But as you also wisely taught me : “No pictures after 10pm!”
Some of the things we experience are for our memories only, and we better keep it that way.
FX,
Thank you for everything. Thank you for who you were. Thank you for showing us what we could become. And thank you for showing us that we can actually change the world.
FX
I owe the depth of my relationship with FX to the love of a woman, and to her love for sausage and cheese. If you think that is far-fetched, I can explain; just remember for now that the real tragedy is with the cheese.
Like many, it all started for me when I entered the land of packets. I marked my computer with the sign of Chaos, and together with a small group, we drove it all the way to a camp site on the outskirts of Berlin. Finally, just like integers overflow, we had made it to the beginning of our journey, and we were sat in a large tent. They entered.
Two brothers from a different mother walked through the space and reached the stage. Long hair, imposing figures, full leather, metalloid heads - nerd glasses - started their presentation and I can positively say that their slides were on fire. In 2003, that wasn’t something you would expect. They left an impression without ever hitting Druck.
Fast forward Xmas 2004. My new family was small but nerdy, and ready to hit the road again. This time we had a guide, and hopped on a bus straight to the city of Berlin. Our small party entered a basement right in the city center, and settled there for a few days. There was Chaos again, it was new to us but it felt nice, cozy, almost comfortable. However, we spoke French, and at the time it raised an exception. We were caught. Someone flying by picked it up and said: “Des Français! J’ai du saucisson et du fromage! Venez!”
We were French, so we went. Little did we know, we were lured to the dark side. Those same figures were there, surrounding us with all black, leather sofas! We were cornered. So we sat, ate their dry meat and their coagulated milk, and humbly introduced ourselves. And then, the chemistry started, when we were asked: “Have you heard about PH-Neutral?”
The real message I am trying to transmit here is: FX’ talent was only equalled by his kindness. This was illustrated once again exactly a year later. There was Chaos again, but this time, penniless and cold, I was looking for a job. On my congress badge, I had written: “Coder 4 Hire (or send ice cream)” and I was interviewing in the corridor track when FX took my arm and said: “No. He works for me.” These words changed my life.
It had never crossed my mind that I could be a security consultant, but there I was; thanks to him. Because FX liked a good joke, sometimes I said I replaced him at that company (he just left it to create his own). Because FX liked a good laugh, he couldn’t help it when my young frail figure entered the big BMW 5-series station wagon company car. I needed it that day because he had spoiled me with a collection of computers: alpha, MIPS, sparc, which of course run NetBSD.
FX was an enabler, and not only on the Cisco CLI. I owe him a lot of what I know, a lot of the confidence I have, and many, many laughs.
GG & HF, FX. You were special.
I miss him already.
FX had the extraordinary talent to leave a lasting impression in human beings through combining his sharp eye for detail and his witty tongue. In one of our rare but deep encounters in a bar, he asked me for the favour of hosting something "because you do and don't tell. You wouldn't use this to pose," he said. That was almost two decades ago. Over time, I hosted unspeakable things that are still unspoken of. In some part due to this single sentence. I never needed more validation. He noticed and cared. People got better because of crossing paths with him in their life. He will be missed.
I first met FX in his favourite bar, where he had scheduled an interview with me. I was 19 years old, he was 29, and he had just founded what would later become Recurity Labs. He ordered two Becks Gold (in his words: "Baby Beers") and we talked about computers.
He ended up hiring me as Recurity Labs' first employee, gave me a business card that spelled "Reverse Engineer" in reverse, bought a massive Thinkpad and put a sticker on it saying "Job in Creation". He told me that, unfortunately, my skills were still insufficient to be a forwards engineer, but that he himself had been stuck at this stage for years.
In the years that were to follow, FX would be my mentor and he would often jokingly call me his "Padawan". FX had a car back then with a license plate containing "B-UG" in it, which he would call the "Bugmobile". As we headed to his car one morning to get to a client, he said "Bug Man and Patchy, to the Bugmobile", and I think that was very cringy, but it was also a beautiful time.
He told me once that he was concerned that hacking was dying, that hackers were no more, and if you dig hard enough in the mailing list archives, you'll see a post by him about this exact topic. On the night where Joernchen and I were welcomed as the youngest members of Phenoelit, he told me that he saw that we were carrying on the torch, and that things are evolving, but that the spirit is still there. He also told me to never become an old hacker. And he told me that he would like to be reincarnated as a lawyer, or a squirrel.
I eventually left the company and we did not leave on good terms, I do not want to sugar coat that. He was quite angry at me for years, but I also believe that he was just disappointed because he knew I wasn't just leaving a job but also a friend.
After he had had his first accident ten years ago, I wrote to his mother and asked if I could visit him. When I visited him, it seemed that he was not angry anymore, and I often wonder if he forgot or forgave, hoping that it was the latter. I realized on that afternoon how much our fallout had been burdening me because of how important he was to me.
I am thankful that he did not pass 10 years ago in that first accident because it gave me the chance to show him that I was still there and his friend. It also meant that he could see what became of me, which I know was important to him. In the last years, he would write to me from time to time telling me how proud he was of me, and I guess there is nothing that expresses more how much he saw himself as an older brother or even father to me. I don't know if he should be proud, as I am certain I never became the brilliant hacker he was, but I will do my best to carry on the torch, and to leave it to the right people when it is my time to go.
Cheers, my friend.
fabs
I met FX for the first time in 2008 at 23C3, down in the hackcenter. Fefe had suggested to me that I invite FX to come on stage for our PowerPoint karaoke. So I asked him.
FX didn't find the request weird at all, he laughed and immediately agreed, and actually showed up that same evening. (PowerPoint karaoke did not prove to be his special expertise.)
He found my later request to contribute to a written report about hacker tools just as unsurprising. If it was really important, he would be involved, he replied.
This resulted in what I believe to be the only "official" collaboration between FX and the Chaos Computer Club. In 2008, four of us wrote a joint written statement to the German Federal Constitutional Court regarding the planned "hacker paragraph" in the Criminal Code. (See: https://erdgeist.org/archive/46halbe/202output.pdf )
The report (in German) is quite timeless and still worth reading today. When it was finished and sent to the Court, he said to me that it had been an honor for him.
It was an honor for me too, FX.
RST in Peace, FX
There are not many people I would credit with having had an immense influence on my personality and development. Felix (FX) Lindner of Phenoelit is one of those people .
On Sunday, I received the news that he has passed away. Although or perhaps precisely because we had not seen or spoken to each other for some time, I would like to share a few words about this extraordinary human being.
Our paths first crossed sometime in the early 2000s – I honestly don’t remember exactly when. Back then, he was already one of the rock stars of the hacker scene, long before the term “infosec” even existed. I was the intimidated, insignificant guy who didn’t quite fit the mold of the hacker community at all, who listened to different music and hardly spoke English. But none of that mattered to FX. I got to know him as someone who simply did not care where people came from or what they brought with them.
As for me, I have brought a lot of questions. And a few beers.
What followed was a journey of several years into the depths of hex editors, disassemblers, and debuggers. FX was a mentor who shared his knowledge and experience without hesitation. Someone who, with patience and dedication, could explain in precise detail how a piece of software works under the hood – and when it might be wise to put on protective gear.
FX had a gift, and it always filled me with great joy to witness him exercise it: He truly lived the hacker mindset – no matter what he was doing or where he was. He had a way of thinking outside the box and instinctively questioning assumptions, always looking for possibilities no one else saw. Whenever he began a sentence with, “What actually happens if…,” something ended up being broken. Every single time.
And the most important “what happens if”-experience he ever gave me, the one that provided the foundation for the rest of my life – was: “What actually happens if I’m staring at something I’ve never seen or heard of before?” And for that, I am endlessly grateful to him. Because the answer, essentially, is: “It’s broken. If you want it to be.”
And if there was only one thing we celebrated back in the days, it was this one: things were meant to break (sometime).
We’ve had a wild time – countless small c0d3&b33r gatherings, the legendary PH-Neutral parties, concerts, park parties, and barbecues on projects 8,000 kilometers away from home. Over and over again, FX brought people together, connected them, and didn’t care in the slightest about preserving elite, secret knowledge.
FX pushed me into the deep end more times than I can count. He opened up new horizons and provided one impetus after another. When he founded his own company, I had the privilege of being part of his team and experiencing project work in the field of unconventional IT security services, far beyond the world of compliance checklists. And even throughout this entire experiment, he continually shared his vision, explained his reasoning, and spoke – sometimes almost excessively humble, but always openly – about his own mistakes.
We eventually lost touch. And yet, FX was and remains a role model for me, and one of the best friends I had. Thanks to his openness, we were all able to benefit from his experience – and I still benefit from it today.
Rest in peace, my friend. I deeply regret that we were unable to see each other one more time.
Cheers, ths
I've heard many marvels about FX long before I've actually met him in person for the first time He was clearly the hacker god for all things Cisco, renowned for pointing out vulnerabilities in their routers.
So I was surprised, when FX presented - at 20c3, together with others from phenoelit - a long list of serious flaws in the (internet-facing) SAP Internet Transaction Server and Web Application Server products.
This was very much unprecedented and unheard of. SAP's software was uncharted security territory, complex with a weird design - but still FX calmly walked through the components pointing out one flaw after the other - which resulted in unauthenticated access to the SAP system. https://www.heise.de/news/20C3-SAP-verstaerkt-im-Visier-der-Sicherheitstester-90923.html
I believe it's hard to overstate the impact that FX's curiosity and skills had on everything he touched and anyone he talked to.
The breadth and depth of his work is mind-boggling. From very technical work, breaking things (literally anything he would set his eyes at), all the way to
p3ki (a distributed PKI) - https://p3ki.com/ - and
langsec (a language-theoretic approach to security) - http://langsec.org/ and https://www.recurity-labs.com/research/FX_Selling_LangSec.pdf
FX was incredibly welcoming for me. - In 2003, our trajectories were quite different, and he could have easily just ignored me. Instead he was very open to talk and discuss things.
Talking with FX was always inspiring, and so were his ph-neutral events, that moved from (at times very dimly lit) off-the-record talks to mandatory mini talks by everyone invited. It was pure heaven. All the best memories and discussions with incredible colleagues.
FX and phenoelit created a bubble in the infosec world that was never "cyber" and free of buzzwords and status claims. Or rather status was implied, as everyone around me was brilliant. Their work was impeccable, and it's great to see how everyone evolved.
I'm grateful to Felix to having introduced me to this, and for all the inspirations. I wished I had stayed in touch with him more closely in the past years.
I'll also remember all his improbable stories.
- The photo shop guy "adjusting" the height of his biometric (!!) passport portrait
- Of graveyard orbits and Russian IR satellites
Also have a look at FX's Phrack Prophile - https://phrack.org/issues/68/2#article
It's so much him.
Mein Abschied von fx.
Dear fx v2, that's what you always called yourself afterwards. Now you're gone. You left us far too soon. Until shortly before, we still had many serious exchanges, but we also constantly joked around in between. That's how I knew v1, and that's how I knew v2 until the very end. So many crazy and beautiful moments, so much knowledge exchange in a patient and intense way, always ready to help and never questioning when it was necessary. Things were done because of reasons and the necessary confidentiality was maintained. You connected people because you didn't just read bits and bytes. You saw communication and exchange as the most important thing. Technology cannot solve social issues. But networking can bring people together so that things work better afterwards. In this respect, you mastered technology and communication in your own unique way, as few other people have done.
I miss you. Thank you for everything.
HonkHase
Let me share a personal story with FX and what I will always remember
from him: He has been always supportive and patient with me with my
technical questions but no only. He always replied with a sense of
humor. Trolled me in order to push me to do things better or with less
sloppyness :) Beyond the security world, sharing vodka mate on the
dance floor listening teckno and discussing with him was fun...
For the joke I lost several times my PH-neutral token and bug him to
recover it and one day that’s what he replied, love it :)
You should be banned for your sloppyness. Actually, I will ask Aluc to print
you a badge in the name of "Sl0ppY" instead.
We knew each other for some time, as we had common friends, but it wasn't until BlackHat Europe 2010 when we became friends.
The Eyjafjallajökull volcano eruption left us stranded in Barcelona for a week and, as the "formerly local" person, I was the go to person to fill the day waiting for the planes to come back. I remember looking for cars to drive back to Berlin and you nearly bought one. The only stopper was the lack of insurance. You could do lots of crazy stuff, but as german, you don't fuck a around with cars. German brands only, Insurance is a must!
I introduced you to my local friends which they still remember you when we get together, and we watched Barça with DT in a crappy bar.
Eyjafjallajökull became a running joke and you even came to a CCCamp with a t-shirt with Eyjafjallajökull printed in it. I guess I never said it, but it meant a lot to me.
This summer I visited Eyjafjallajökull and I sent you a picture of it, which trigger some funny conversations and a reconnection. Now, I wish I had been more active.
Hack the planet my friend.
DEF CON 9 was my first DEF CON. For sure I was interested in hacking, but for trade I was a "networking guy". Suddenly this dude got on stage and started talking about breaking HSRP, IRDP and that "this one packet talks louder than others, that's a broadcast packet."
Okay, I was at the right place. I understood everything in that presentation, and suddenly my presence there made sense.
Fast forward to 22C3, a mutual friend formally introduced me to FX at c-base. We talked for a few minutes and i was probably an idiot.
The following year I returned to Berlin for 23C3 and the short of it is that I ended-up having a very interesting chat about responsible disclosure. I listened, I was less of an idiot, I put my reputation on the line and things turned out okay.
FX and I ended up hanging out a bit in Kuala Lumpur for Hack in the Box and then I met Felix. I told him we were planning to start a new security conference and asked if he would be willing to go speak. I explained the conference format, and he did not blink. "I am in! And, btw, you should go to the next PH". And we became friends.
He flew himself to the first ysts.org to present. We took him to a Brazilian BBQ place. I have never seen FX smile that big. We returned to that restaurant the day before he flew back home.
Every once in a while we talked at random times of the year, about random stuff.
But every Christmas he would message me, and I would do the same on his bday.
As to many, he was a good mentor. I was not a "cool security researcher or a decent hacker" and, I never became one. But he showed me that, somehow, I belonged.
At DEF CON 25, after checking with y'all if it was okay, I rallied people FX knew to record short "get well" video messages to him. I compiled them and it made its way to him. A few years later, he (politely) said he enjoyed it. Watching it now proves how much he meant to a lot of people, and I can't help imagining Dan welcoming Felix with a big smile and a warm hug, wherever they are now.
Felix was a connector, skilled at complex problem-solving, including connecting the right people based on their skills.
In the past few years I visited Berlin once a year, and Felix and I worked our schedules to have a meal, a good conversation and quite a few laughs. He always said "I lilke to talk to intelligent people who get my jokes". Coming from him, that was a huge compliment.
He will be missed, but helped shape the community with his values, and he will never be forgotten. Godspeed FX!
-effffn
It's true that the best of our generation leaves us early. I cannot understand why, but we have to carry the torch.
He made history and had an impact on the land of packets in a way that probably only historians will be able to uncover in the future, looking through the famous incidents and vulnerabilities of the first two decades of the 02000s.
There was a time when ph-neutral was the top of the hacker world but nobody knew it.
Only the people who have been there partying, drinking shots of Jager and having fun until dawn can understand.
The short German hacker, how he used to define himself with me, was the most magnetic personality you could ever met.
We met by chance, because we both loved barcodes, he handed me the sticker for the phenoelit party at c base @ 24c3 and this changed the course of my life.
He was interested in everything and everyone and could be the most humble person you ever met.
He could be also the most difficult.
He opened me the doors of the land of packet: taught me BGP in a bar in Oranienstraße, helped me with my homeworks and then dropped me in the wild.
He was one of those people that you meet once in a timeline. He was able to collect in same room the highest concentration of leet, from both sides, and make them party together, even if they hated each other.
Reading the memories in this page I know he would be pleased. He loved YSTS and the Ada Lovelace t-shirt, the crazy ExcaliburCon in China, when they managed to hack gold bricks out of the ATM in Dubai, the party at vulcanocon (where I left wiith the last plane before they close the airspace) and so many other things of those crazy years.
But, most of all, he was proud of Phenoelit and Recurity Labs and I know that his spirit will live through the work of Mumpi, Joern and the others.
Phenoelit is the hacker version of Company of the Ring and the treasure to protect is the real spirit of hacking, before all the money and mainstream.
I am still in shock because I always thought we still had time to restore the balance in the land of packets. I think it will take a long time to process that all this is real. It was too soon.
I now imagine him and Dan on the couch on stage like it happened in a ph neutral ages ago. They are going to find that one vulnerability in the DNS also in heaven and one day, we will meet again on the other side.
Until then, I will look for him in the sky and continue to believe that there is a timeline out there where we are all a very happy family and we will grow old together.
Dear FX,
when we met for the first time at Black Hat Amsterdam 2001, it was kinda love on the first sight. It was a wild mixture of deep technical interests and likewise deep emotional feelings i still cannot fully comprehend.
From there it was a wild ride whenever we met. PH-Neutral was the most impressive series of hacking events and legendary parties i ever encountered, and i am still very honoured that i was allowed to be part of your family for the next 25 years, regardless if it was about professional work, extended JRP workshops or just messing around. I met so many incredible people because of you, it’s unreal when i now think back about all of that.
I also will never forget the week in Barcelona when Eyjafjallajökull exploded and grounded thousands of hackers for an enforced week of serious quality-time. We stayed in pretty close contact for the whole time, with FX v1, and, after the accident, also with FX v2, frequently chatting, voice-calling and physical visits. I always enjoyed your company, regardless of the reason; whenever we did something together it was just legendary amazing. I learned so much from you, part of it technical, but also and maybe even more important, emotionally. I really enjoyed your „culture of hugging (hacker) friends“ and i proudly adopted that to my universe. My dear friend fx you will be missed hard! Hack Heaven, hack Hell, hack the planet!