Remembering David Harley: A Cybersecurity Luminary
07 Nov 2025
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7 min. read
The cybersecurity community mourns the loss of David Harley, a renowned cybersecurity researcher, author, and mentor, who passed away at the age of 76 last week.
Despite entering the field of IT later in life, David went on to establish a remarkable career in cybersecurity that spanned from the early era of computer viruses to the modern age of ransomware. His legacy includes a tenure as ESET Senior Research Fellow until his retirement in 2018.
With a diverse academic background in modern languages, social sciences, and computer science, David recognized early on that the most critical vulnerabilities were often human rather than technical. This insight permeated much of his later work, especially in his studies on the psychology of cybercrime. While his expertise extended to analyzing malware trends and engaging with antimalware product testing standards, David was also a prolific author, editor, and conference speaker.
Writing and public speaking were not just tasks for David but avenues for connecting with peers and advocating for a safer online environment. WeLiveSecurity proudly preserves a portion of David’s extensive written works, while his numerous books and scholarly articles are documented here.
If you had the privilege of learning from David, consider passing on that knowledge. He believed in cybersecurity as a public good and was dedicated to enhancing internet safety for all. Apart from his cybersecurity contributions, David was also a talented singer, songwriter, and guitarist. Experience his music here.
Former colleagues fondly recall David as a wellspring of knowledge and a meticulous communicator whose impact on the field and his collaborators was enduring.
Andrew Lee, ESET Vice President of Government Affairs, shared his memories of David:
“In 1999, I crossed paths with a man who would become a friend, a colleague, and a collaborator on various projects. At that time, I was spearheading the implementation of a security and antivirus platform within a government agency. On a message board called alt.comp.virus, frequented by antivirus professionals, I encountered David Harley, who then worked for the NHS as the head of computer security. David’s insights and advice on the forum were invaluable and greatly aided me in my role.
Our first in-person meeting occurred at the ‘Infosec’ conference in late 1999, where we immediately connected over shared interests beyond cybersecurity. I vividly remember seeking David’s guidance on a paper about Linux malware during that initial encounter. Recognizing his writing prowess, I requested his assistance, leading to a collaborative presentation at the EICAR conference in 2001. Our partnership evolved seamlessly, with David’s expertise in crafting content complementing my presentation skills.
Subsequently, I transitioned from government service to ESET, a move that may not have materialized without David’s support during those early conference collaborations. Our professional relationship continued at ESET, where we collaborated on numerous white papers and presentations. I also had the privilege of contributing to one of his books on security.
Bonding over our mutual love for traditional British folk music, David and I shared many musical moments. During the pandemic, I assisted him in enhancing and sharing his musical works, underscoring his talent as a guitarist, singer, and songwriter. David’s gentle demeanor, combined with his wit and intellect, made a lasting impression on everyone he encountered.
Our collaboration not only enriched our professional lives but also fostered a deep friendship. I will always cherish our shared experiences and the profound impact he had on me. My thoughts are with Jude, David’s daughter, and all those who cherished him.
Rest in peace, my dear friend.”
Bruce P. Burrell, ESET Research Fellow, shared his reflections on David:
“My introduction to David likely occurred through online forums like VIRUS-L/comp.virus in the late 80s or early 90s. Our first face-to-face meeting was probably at the Virus Bulletin conference in Boston in 1995 or in San Francisco at VB 97. By then, meeting David felt like reconnecting with an old friend.
Prior to our in-person encounters, our interactions on the alt.comp.virus newsgroup paved the way for collaborating on an FAQ with George Wenzel. David’s exceptional writing skills drove the project, with George and I providing minor contributions. I vividly recall staying at David’s London flat in 1998 and meeting his daughter Katie, a delightful extension of David’s warmth and kindness.
Upon joining ESET, I had the privilege of working closely with David and Nick FitzGerald, forming a trio of wordsmiths. The experience of collaborating with these two luminaries on a daily basis was both enriching and enlightening. David’s retirement marked the end of an era, leaving a void that will be deeply felt.
Although our post-retirement interactions were fewer than I would have liked, the impact of his mentorship and friendship remains indelible. You will be dearly missed, David.”
Righard Zwienenberg, ESET Senior Research Fellow, shared his heartfelt tribute to David:
“The news of David’s passing fills me with profound sorrow. Over the past three decades, I had the privilege of sharing many memorable moments with him, whether on stage during presentations or through our shared passion for music. Our jam sessions, with David on guitar and myself on drums, are cherished memories that I will hold dear.
David was a walking encyclopedia, always ready to delve deeper into any topic with additional resources and insights. While he may have been self-deprecating about his presentation skills, his vast knowledge and storytelling prowess never failed to captivate audiences.
May his legacy endure through the music and memories we created together.”
Our deepest condolences go out to David’s family and loved ones.
Explore more about David Harley’s life and contributions here.
