In memoriam: David Harley

Former colleagues and pals bear in mind the cybersecurity researcher, creator, and mentor whose work bridged the human and technical sides of safety

07 Nov 2025
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7 min. learn

The cybersecurity group misplaced one in every of its luminaries with the passing of David Harley final week, on the age of 76.

Regardless of being a self-described late entrant to IT, David went on to forge a protracted and distinguished profession in cybersecurity that stretched from the early days of pc viruses till the age of recent ransomware and included a tenure as ESET Senior Analysis Fellow till his retirement in 2018.

With a tutorial background in trendy languages, social sciences, and pc science, David understood early that probably the most harmful vulnerabilities weren’t all the time technical, however human. This lesson would echo by means of a lot of his later work, notably in his writings concerning the psychology of cybercrime. His experience ranged broadly, nevertheless, and in addition encompassed evaluation of malware developments and engagement with the requirements of antimalware product testing.

A prolific creator, editor, and convention speaker, David considered writing and public talking as an extension of analysis and a possibility to attach with friends and, certainly, anybody else dedicated to creating the web a safer place for everybody. WeLiveSecurity is proud to protect a part of David’s huge physique of written work; in the meantime, the varied books and scholarly articles that he authored, co-authored, and edited are listed right here.

In the event you ever had the privilege of studying from David, take into account paying it ahead. David himself was proud to be a part of the cybersecurity group and considered cybersecurity as a public good. (He was additionally an completed singer, songwriter, and guitarist. Pay attention for your self right here.)

Former colleagues, in the meantime, bear in mind David as a fountain of data and a meticulous wordsmith who left an enduring mark on the sector and all those that labored with him.

Says ESET Vice President of Authorities Affairs Andrew Lee:

“In 1999 I met a person who would grow to be a buddy, a colleague, and a collaborator on many tasks through the years.

On the time, I used to be working in a authorities workplace, establishing the primary absolutely carried out safety and antivirus platform all through the company. There was a message board, the alt.comp.virus newsgroup (type of like a really early social media for geeks), the place others concerned within the antivirus sphere would focus on. On that discussion board, on the time working for the NHS as its pc safety head, was a person named David Harley. On that board, many conversations would happen, and David would typically give his enter, which was related, knowledgeable, and all the time value studying. He, amongst others, helped me tremendously in offering info and recommendation that helped me do my job.

At a convention referred to as ‘Infosec’ (sadly lengthy defunct), I lastly met David, in late 1999, and we hit it off instantly, sharing many extra pursuits than simply safety. Throughout that first assembly, over pizza, I mentioned an concept that I used to be engaged on – a paper on Linux malware. I knew David was an excellent author, so I requested him for some suggestions. I’ve all the time been good at having concepts, however with extreme ADHD (undiagnosed on the time), I used to be merely unable to get them onto the web page in a logical means, I converse much better than I write. David virtually instantly provided to assist me write the paper, and we ultimately introduced it on the EICAR convention in 2001, in Copenhagen. I did the presenting, because it was not David’s energy on the time. We complemented one another effectively. We’d bounce concepts round, he would ship a draft, I might add my contributions, then he would edit it into one thing usable. Then I would current our work.

Finally, I left authorities and joined ESET – and it is true to say that with out David serving to me with these early convention papers, I would by no means have had the possibility to satisfy the ESET of us. David and I stored in contact, commonly assembly up at trade conferences, and ultimately, it was an enormous pleasure to have the ability to rent him into ESET, the place as soon as once more, we labored on many white papers and shows collectively. He additionally wrote books on safety, one in every of which I had the pleasure of contributing to.

We additionally bonded over music. David was, like me, an enormous fan of conventional British folks music, and was himself a really completed guitarist, singer, and songwriter. Through the pandemic, I helped him clear up, remix, and grasp a few of his earlier work, and it is a disgrace that extra individuals didn’t uncover his songs, as they’re stunning, effectively written, and infrequently deeply transferring.

David was a quiet man, he was mild, sort, but in addition humorous and intelligent. His work was essential, and whereas the trade has moved on, a lot of the recommendation he wrote remains to be related and very important in the present day. His reserved nature typically hid from others the deep mind and perception that David held.

In some small half, I hope our work collectively helped him too; as is commonly mentioned, two heads are higher than one. I’ll all the time bear in mind when he met his true ‘second head’, Jude, in Berlin, and their lasting bond, friendship, and love was one thing that was apparent to those that met them.

Above all, David was my buddy. I’ll miss him significantly.

My like to Jude, David’s daughter, and all who knew and beloved him.

Relaxation in peace my buddy.”

Says ESET Analysis Fellow Bruce P. Burrell:

“I am not fairly positive after I first met David – in all probability although VIRUS-L/comp.virus within the late 80s or early 90s. I am not sure about after I met him in particular person, both, however I am fairly positive it was in 1995, on the Virus Bulletin convention in Boston. Or possibly in San Francisco at VB 97 (the convention report mentions him, so I do know he was there). Each time it was, by that point it was like assembly an outdated buddy.

In all probability a bit earlier than our first face-to-face assembly, the alt.comp.virus newsgroup got here into existence, and I had many interactions with David there. Finally, it grew to become clear that an FAQ was wanted for the newsgroup, and a triumvirate of David, George Wenzel, and I began placing one collectively. Extra precisely, David did virtually all the placing, whereas George and I contributed a bit or two; I additionally did a wee little bit of wordsmithing. Emphasis on ‘wee’: David’s writing expertise had been superlative, so it was principally simply sanity-checking.

Be aware additionally that, whereas the gentlest and kindest of individuals, he had a wickedly intelligent wit – simply browse the titles and headers of his writings.

I overnighted at his flat in London in the summertime of 1998, and later that yr, at VB 98, I met the common occupant of that room – his lovely eight-to-ten-year-old(?) daughter Katie. I imagine that she adopted her father into pc safety; whether or not or not she’s nonetheless in that subject, he had each purpose to be happy with her.

Through the years, we would been in common contact – however after I joined ESET, we quickly fashioned one other trio of wordsmiths – David, Nick FitzGerald, and myself. It was an important pleasure – and studying expertise – to work with these two every day, as a substitute of the occasional one-off emails and the all-too-rare convention or ‘I simply occur to be on the town’ conferences. I used to be lucky to have the ability to work with him carefully for a number of years, till his retirement. Not an early retirement, however actually sooner than I would have favored it to be!

Submit-retirement, we stayed in contact, however on reflection, not practically sufficient. I shall miss you tremendously.”

Says ESET Senior Analysis Fellow Righard Zwienenberg:

“I’m really saddened to listen to this information. Having identified David for over three many years, I used to be lucky to share many memorable moments with him, on stage throughout shows and thru our mutual love of music. We had some good periods along with David on guitar and myself on drums. He can be deeply missed by me.

David was a ‘strolling Wikipedia’. Everytime you despatched him an summary or a full paper to edit, he all the time returned it with hints to extra materials, references to supporting materials, and so on. Many individuals know that for all his brilliance as a author and editor, he was ‘clumsy’ as a presenter. Typically shedding monitor, having his notes within the improper order so he was speaking about slides but to come back however not the present one, laughing about his personal errors … All people who actually knew him will bear in mind, ‘Oh pricey …’, which was his typical means of apologizing on stage whereas presenting and but once more shedding monitor. But, resulting from his huge data on the subject he was presenting or ready-when-needed historical past when the Q&A time was there, he all the time attracted a big crowd …

Might his reminiscence dwell on by means of the music and moments we shared.”

We provide our heartfelt condolences to David’s household and pals.

Right here’s the place you may study extra concerning the life and work of David Harley: