--- title: Inside FakeAgent: How a Claude Desktop Malvertising... description: Huntress documented a malvertising campaign dubbed FakeAgent that hit 29 organizations between July 21-22, 2026, after victims searched for the Claude Desktop... canonical: https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Inside FakeAgent: How a Claude Desktop Malvertising Campaign Hit 29 Organizations with SectopRAT | daily.dev og:description: Huntress documented a malvertising campaign dubbed FakeAgent that hit 29 organizations between July 21-22, 2026, after victims searched for the Claude Desktop... og:url: https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn og:image: https://api.daily.dev/og/posts/iHAL6pyPn.png og:image:alt: Inside FakeAgent: How a Claude Desktop Malvertising Campaign Hit 29 Organizations with SectopRAT 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. # Inside FakeAgent: How a Claude Desktop Malvertising Campaign Hit 29 Organizations with SectopRAT **[Huntress Blog](https://daily.dev/sources/huntress-blog)** · 15 min read · 0 upvotes · 0 comments ## Summary Huntress documented a malvertising campaign dubbed FakeAgent that hit 29 organizations between July 21-22, 2026, after victims searched for the Claude Desktop app on Bing and clicked a sponsored ad linking to a malicious public Claude Artifact hosted on the legitimate claude.ai domain. The fake download page redirected victims to attacker-controlled domains serving a trojanized ClaudeDesktop.exe that used DLL sideloading (via a tampered libcef.dll alongside a legitimate JetBrains jcef_helper.exe) to deploy SectopRAT, a .NET-based remote access trojan that steals credentials, credit card data, and files. The malware used VMProtect packing, GPU-based anti-VM checks, and a DirectX shader-based decryption routine to evade analysis, and stored command-and-control rotation data on the Ethereum blockchain (EtherHiding) via BSC transactions. Huntress used Claude Opus to help reimplement the AES-256-CTR decryption and SM5 shader emulation, eventually recovering the live C2 address 2.24.131.246. OSINT pivoting tied the operator to prior campaigns including a fake Docker Desktop distribution and a domain previously seized by Microsoft's Operation Endgame. The malicious artifact had 7,100 views before Anthropic removed it. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the FakeAgent malvertising campaign that used Claude Desktop as a lure? FakeAgent is a malvertising campaign that hit 29 organizations between July 21 and 22, 2026, where victims searching Bing for the Claude desktop app clicked a sponsored ad leading to a malicious public Claude Artifact hosted on the legitimate claude.ai domain. Clicking download redirected victims to claude.ai.download-app[.]us, serving a trojanized ClaudeDesktop.exe that ultimately installed SectopRAT, a credential and financial data-stealing RAT. _Security teams tracking emerging malvertising tactics like this can follow threat writeups on daily.dev._ ### How did attackers hide command-and-control infrastructure in the SectopRAT campaign? Attackers stored command-and-control rotation data in Ethereum Binance Smart Chain (BSC) transactions, a technique called EtherHiding, referencing a contract address with no cryptocurrency balance whose function calls resolved to an encrypted payload location. This let the operator rotate C2 servers simply by posting new blockchain transactions, making takedown far harder than with traditional domain-based infrastructure. _Anyone researching blockchain-based C2 evasion can dig into detailed incident breakdowns like this on daily.dev._ ### How was Claude AI used to help reverse-engineer the SectopRAT malware's shader-based decryption? Claude Opus assisted analysts in reimplementing an SM5 bytecode interpreter to emulate a malicious DirectX shader that performed AES-256-CTR decryption with a modified MixColumns function, since the malware delegated decryption to the GPU to evade standard reverse-engineering tools. Claude helped recover the AES S-box, Rcon sequence, and key material, though a manually transcribed one-byte key error initially blocked successful decryption until humans caught it. _Developers curious how LLMs assist in security reverse-engineering can find similar deep dives on daily.dev._ ## Similar posts on daily.dev - [How Threat Actors Are Turning Trusted AI Platforms Into an Attack Surface](https://daily.dev/posts/how-threat-actors-are-turning-trusted-ai-platforms-into-an-attack-surface-oxjgyttbh) · BleepingComputer · 0 upvotes · 0 comments - [Threat Actors Abuse claude.ai Shared Chat for ClickFix Malvertising Campaign](https://daily.dev/posts/threat-actors-abuse-claude-ai-shared-chat-for-clickfix-malvertising-campaign-zdoc6dupj) · Trend Micro · 1 upvotes · 0 comments - [Red teamers turned Claude Desktop into a double agent to do their evil bidding](https://daily.dev/posts/red-teamers-turned-claude-desktop-into-a-double-agent-to-do-their-evil-bidding-l5nrlqiyd) · The Register · 1 upvotes · 0 comments - [The AI Attack Surface: How Threat Actors Abuse Trusted AI Platforms](https://daily.dev/posts/the-ai-attack-surface-how-threat-actors-abuse-trusted-ai-platforms-clbkcskrj) · Huntress Blog · 1 upvotes · 0 comments --- Tags: [#cyber](https://daily.dev/tags/cyber), [#malware](https://daily.dev/tags/malware), [#claude](https://daily.dev/tags/claude), [#reverse-engineering](https://daily.dev/tags/reverse-engineering) [View this post on daily.dev](https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn) ```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":"Inside FakeAgent: How a Claude Desktop Malvertising Campaign Hit 29 Organizations with SectopRAT","url":"https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn"},"datePublished":"2026-08-18T16:16:34.760Z","dateModified":"2026-08-18T19:20:01.046Z","description":"Huntress documented a malvertising campaign dubbed FakeAgent that hit 29 organizations between July 21-22, 2026, after victims searched for the Claude Desktop...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/affc6a6180bcc32ff2db36be2b083fcd?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/affc6a6180bcc32ff2db36be2b083fcd?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Huntress Blog","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":"Huntress Blog","logo":"https://media.daily.dev/image/upload/s--kDC1MDsj--/f_auto,q_auto/v1780213277/logos/huntress-blog?_a=BAMAMiWQ0","url":"https://daily.dev/sources/huntress-blog"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"cyber,malware,claude,reverse-engineering","timeRequired":"PT15M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Huntress Blog","item":"https://daily.dev/sources/huntress-blog"},{"@type":"ListItem","position":3,"name":"Inside FakeAgent: How a Claude Desktop Malvertising Campaign Hit 29 Organizations with SectopRAT"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/inside-fakeagent-how-a-claude-desktop-malvertising-campaign-hit-29-organizations-with-sectoprat-ihal6pypn#faq","mainEntity":[{"@type":"Question","name":"What is the FakeAgent malvertising campaign that used Claude Desktop as a lure?","acceptedAnswer":{"@type":"Answer","text":"FakeAgent is a malvertising campaign that hit 29 organizations between July 21 and 22, 2026, where victims searching Bing for the Claude desktop app clicked a sponsored ad leading to a malicious public Claude Artifact hosted on the legitimate claude.ai domain. Clicking download redirected victims to claude.ai.download-app[.]us, serving a trojanized ClaudeDesktop.exe that ultimately installed SectopRAT, a credential and financial data-stealing RAT. Security teams tracking emerging malvertising tactics like this can follow threat writeups on daily.dev."}},{"@type":"Question","name":"How did attackers hide command-and-control infrastructure in the SectopRAT campaign?","acceptedAnswer":{"@type":"Answer","text":"Attackers stored command-and-control rotation data in Ethereum Binance Smart Chain (BSC) transactions, a technique called EtherHiding, referencing a contract address with no cryptocurrency balance whose function calls resolved to an encrypted payload location. This let the operator rotate C2 servers simply by posting new blockchain transactions, making takedown far harder than with traditional domain-based infrastructure. 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