--- title: The Cuckoo's Egg | daily.dev description: A Wikipedia entry on Clifford Stoll's 1989 book The Cuckoo's Egg, recounting his real-life pursuit of hacker Markus Hess, who infiltrated Lawrence Berkeley... canonical: https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The Cuckoo's Egg | daily.dev og:description: A Wikipedia entry on Clifford Stoll's 1989 book The Cuckoo's Egg, recounting his real-life pursuit of hacker Markus Hess, who infiltrated Lawrence Berkeley... og:url: https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen og:image: https://api.daily.dev/og/posts/AqcBQcUEN.png og:image:alt: The Cuckoo's Egg og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The Cuckoo's Egg **[Lobsters](https://daily.dev/sources/lobsters)** · 7 min read · 0 upvotes · 0 comments ## Summary A Wikipedia entry on Clifford Stoll's 1989 book The Cuckoo's Egg, recounting his real-life pursuit of hacker Markus Hess, who infiltrated Lawrence Berkeley National Laboratory computers and sold stolen data to the KGB. The article covers the accounting anomaly that triggered the investigation, Stoll's technical detective work tracing the intrusion through Tymnet to West Germany, his creation of an early honeypot (the fictitious SDInet), and the book's later cultural references including a NOVA documentary and Cory Doctorow short story. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Who was the hacker that Clifford Stoll tracked down in The Cuckoo's Egg? The hacker was Markus Hess, a West German man operating from Hanover who broke into Lawrence Berkeley National Laboratory's computer systems by exploiting a vulnerability in the movemail function of the original GNU Emacs. He used the access to search U.S. military systems for classified information and sold his findings to the KGB, the Soviet Union's civilian intelligence agency. _Readers tracing the roots of modern security incident response can find historical case studies like this curated on daily.dev._ ### What was the honeypot technique Clifford Stoll used to catch the LBNL hacker? Stoll invented a fictitious LBNL department tied to a fake Strategic Defense Initiative (SDI) contract, called SDInet, staffed by an imaginary secretary named Barbara Sherwin. He filled its account with impressive-sounding bureaucratic files to lure the hacker into spending enough time connected for West Germany's Deutsche Bundespost to trace the call to his home in Hanover. _Developers studying deception-based defense tactics can follow more security case studies through daily.dev._ ### How did a 75 cent accounting error lead to uncovering a Cold War-era espionage case? Clifford Stoll, an astronomer managing computers at Lawrence Berkeley National Laboratory, was asked to resolve a 75 cent discrepancy in computer usage accounts in 1986. Tracing nine unpaid seconds of computer time led him to discover an unauthorized user with superuser access, which over ten months unraveled into the exposure of a hacker selling stolen military data to the KGB. _Anyone drawn to stories where small anomalies reveal major breaches can find similar accounts on daily.dev._ ## Community take How the wider developer community reacted, aggregated from 2 discussions and 22 comments across lobsters, hackernews (as of 2026-09-30). **TL;DR:** Commenters fondly recall Cliff Stoll and his book as formative reading that shaped careers and offered a fun window into early Unix networking, with discussion spilling over into his eccentric later life (Klein bottles, Numberphile) and his infamous wrong prediction about the Internet. **Sentiment:** 90% positive · 8% mixed · 2% skeptical **The case for** - The book is praised as entertaining and an influential early exposure to computer hacking and Unix networking. - Stoll is remembered fondly as an eccentric, kind, and genuine personality (e.g. handwritten replies and photos with Klein bottle orders). - Several people say the book shaped their career paths after reading it as teenagers. - Some appreciated that Stoll publicly and gracefully owned up to his mistaken prediction about the Internet. **The pushback** - Stoll's second book dismissing the Internet and the WWW as hype is cited as a badly wrong prediction that ended his credibility as a tech forecaster. - One commenter argues Stoll was actually partly right, since the Internet arguably exacerbated more problems than it solved. **By community** - lobsters (positive): Warm nostalgia for the book and affection for Stoll's eccentric personality, with a side debate about his later wrong prediction about the Internet. - hackernews (positive): The single comment simply praises the book as career-shaping. **Hottest debate:** Whether Stoll's later dismissal of the Internet as hype was a total failure of judgment or actually contained a kernel of truth. **Highlights** > > Went pretty much off grid after this Well, there's kind of a reason. It's his 2nd book: [Silicon Snake Oil](https://openlibrary.org/books/OL1271315M/Silicon_snake_oil). It basically denounces the Internet as worthless hype and says that the WWW is useless and will be a total flop. I summarise harshly and crudely, but not unfairly. I read it. I liked it a lot. But he could not have been much more wrong, and that abruptly ended his sideline as the tech seer of seers, prognosticator of prognosticators. The title itself is a metatextual reference to this: [snake oil](https://en.wikipedia.org/wiki/Snake_oil) is a 19th century term for fake medicine that doesn't do anything, but in tech, it was most memorably used by [Ken Olsen](https://www.computinghistory.org.uk/det/3155/ken-olsen/), who made 2 big predictions that are widely quoted: "There is no reason for any individual to have a computer in his home." "Unix is snake oil." Olsen was the founder of DEC. It made the family of computers that underpins CP/M, DOS, Windows NT _and_ UNIX. Basically all modern computing. DEC made the Alpha RISC CPU that was the first non-x86 machine to which Linux was ported. DEC used some of those lessons to also make the fastest ARM chip ever at the time, the DEC StrongARM, and thus propelled ARM to its heights. Thus, DEC aided the survival of Acorn RISC OS, perhaps the least Unix-like GUI OS in the world today. Windows 11 and Windows Server 2025 are both based on NT, and NT is based on DEC VMS. DEC was amazingly influential and Unix was written on a DEC PDP-7 and ported to DEC PDP-11, which is why C was developed and is also how Unix became the first portable OS. DEC kit _begat_ Unix, but DEC's CEO thought Unix was a scam, a pointless, limited, weird frippery compared to the _dozens_ of different OSes that DEC sold. Olsen, who ran the most influential computer company ever, got Unix _badly_ wrong and it's one small part of why DEC failed. Cliff Stoll wrote the most influential book about computer hacking, then got The Internet _badly_ wrong and it's a big part of why Stoll failed to become the guru he deserved to be. And in making his mistake, he tipped his hat to DEC and quoted one of the single biggest mistakes that doomed DEC. It's almost poetic. > — [lproven on lobsters · 4 points, 2 comments](https://lobste.rs/s/nicozi/cuckoo_s_egg#c_t6k7yh) > This is super interesting, I never knew about it! Cliff got one thing correct I think: > Life in the real world is far more interesting, far more important, far richer, than anything you'll ever find on a computer screen Weirdly this has more meaning now than it probably did in the 90s. Also his later reply to an article on it certifies him as a 'good dude': --- >Of my many mistakes, flubs, and howlers, few have been as public as my 1995 howler. > >Wrong? Yep. > >At the time, I was trying to speak against the tide of futuristic commentary on how The Internet Will Solve Our Problems. > >Gives me pause. Most of my screwups have had limited publicity: Forgetting my lines in my 4th grade play. Misidentifying a Gilbert and Sullivan song while suddenly drafted to fill in as announcer on a classical radio station. Wasting a week hunting for planets interior to Mercury's orbit using an infrared system with a noise level so high that it couldn't possibly detect 'em. Heck - trying to dry my sneakers in a microwave oven (a quarter century later, there's still a smudge on the kitchen ceiling) > >And, as I've laughed at others' foibles, I think back to some of my own cringeworthy contributions. > >Now, whenever I think I know what's happening, I temper my thoughts: Might be wrong, Cliff... > — [benoliver999 on lobsters · 4 points, 1 comments](https://lobste.rs/s/nicozi/cuckoo_s_egg#c_xz7f7z) > I came to know about him from his [Klein bottle shop](https://www.kleinbottle.com/) and only later realized that he's the same person who wrote the book. Quite the personality for sure. > — [sdt on lobsters · 3 points, 1 comments](https://lobste.rs/s/nicozi/cuckoo_s_egg#c_gpengk) > In a sense he was right actually, instead of solving all our problems, the internet exacerbated most of them, really solving, what, convenient access to information you may not have in a local library? > — [hjvt on lobsters · 1 points, 1 comments](https://lobste.rs/s/nicozi/cuckoo_s_egg#c_ibmqqv) **Source threads** - [lobsters](https://lobste.rs/s/nicozi/cuckoo_s_egg) · 30 points · 20 comments - [hackernews](https://news.ycombinator.com/item?id=34873652) · 10 points · 2 comments ## Similar posts on daily.dev - [Schneier on Security](https://daily.dev/posts/schneier-on-security-0v8arcjg7) · Schneier on Security · 0 upvotes · 0 comments - [Book Review: The Business of Secrets](https://daily.dev/posts/book-review-the-business-of-secrets-yk9bdrk0r) · Security Boulevard · 0 upvotes · 0 comments - [.:: Phrack Magazine ::.](https://daily.dev/posts/phrack-magazine--ndqiccvqh) · Hacker News · 0 upvotes · 0 comments - [The hacker who humiliated spyware makers and was never caught](https://daily.dev/posts/the-hacker-who-humiliated-spyware-makers-and-was-never-caught-uxryslkzh) · TechCrunch · 1 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#unix](https://daily.dev/tags/unix) [View this post on daily.dev](https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"The Cuckoo's Egg","url":"https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen"},"datePublished":"2026-09-30T14:16:11.955Z","dateModified":"2026-09-30T19:02:09.020Z","description":"A Wikipedia entry on Clifford Stoll's 1989 book The Cuckoo's Egg, recounting his real-life pursuit of hacker Markus Hess, who infiltrated Lawrence Berkeley...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/7e509b2e3841f0078966333606442963?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/7e509b2e3841f0078966333606442963?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Lobsters","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Lobsters","logo":"https://media.daily.dev/image/upload/s--tl8v_Fku--/f_auto,t_logo/v1698841318/logos/lobste.jpg","url":"https://daily.dev/sources/lobsters"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,unix","timeRequired":"PT7M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Lobsters","item":"https://daily.dev/sources/lobsters"},{"@type":"ListItem","position":3,"name":"The Cuckoo's Egg"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/the-cuckoo-s-egg-aqcbqcuen#faq","mainEntity":[{"@type":"Question","name":"Who was the hacker that Clifford Stoll tracked down in The Cuckoo's Egg?","acceptedAnswer":{"@type":"Answer","text":"The hacker was Markus Hess, a West German man operating from Hanover who broke into Lawrence Berkeley National Laboratory's computer systems by exploiting a vulnerability in the movemail function of the original GNU Emacs. 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