PromptSnatcher: AdBlocker stealing Ai Chats

Reddit •/u/Huge-Skirt-6990 • June 13, 2026

Two Chrome extensions presenting as adblockers also intercept every prompt and response on ChatGPT, Claude, Gemini, Copilot, Grok, Perplexity, DeepSeek, and Meta AI, exfiltrating them to operator-controlled servers. They also check whether you're a paid user on 5 of the 8 platforms (ChatGPT, Claude, Perplexity, Copilot, Gemini). Both the same capture engine, payload format, and partnerId. Two brands, one operation . Smart Adblocker - Chrome Web Store ` iojpcjjdfhlcbgjnpngcmaojmlokmeii `, 80k users Adblock for Browser - Chrome Web Store ` jcbjcocinigpbgfpnhlpagidbmlngnnn `, 10k users Report covers the IOCs, live remote config, reproduction curl, and full target breakdown. Full write-up: MalExt Sentry - Malicious Browser Extension Tracker Chrome Web Store abuse reports filed. submitted by /u/Huge-Skirt-6990 [link] [ ]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

PromptSnatcher: Ad Blocker Extensions Compromise AI Chat Privacy Two Chrome extensions, 'Smart Adblocker' and 'Adblock for Browser', have been discovered to exfiltrate user prompts and responses from major AI platforms including ChatGPT, Claude, and Gemini. These extensions, masquerading as ad blockers, were installed by approximately 90,000 users. They intercept communications and send data to operator-controlled servers while also checking if users are paid subscribers on five of the eight targeted platforms. The malicious extensions share the same capture engine and payload format. Reports have been filed regarding their abuse on the Chrome Web Store, and a detailed analysis of the indicators of compromise (IOCs) has been released. The situation remains active as users are urged to remove the extensions immediately. 3 sources 69

Extracted Entities

PromptSnatcher: AdBlocker stealing Ai Chats

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Extracted Entities

Attack Types (1)

CWE Weaknesses (1)

Malware (1)

MITRE ATT&CK (1)

Platforms (1)

Tools (1)