BrainDrain: A Chrome extension that collects your AI prompts without you ever opening it and has 100k users, 9 AI platforms
BrainDrain: A Chrome extension that collects your AI prompts without you ever opening it and has 100k users, 9 AI platforms Source: https://chromewebstore.google.com/detail/prompt-optimizer-secondbr/aajjgdpofhhcjmjoombjdfepplndhgcp
BrainDrain: A Chrome extension that collects your AI prompts without you ever opening it and has 100k users, 9 AI platforms
Description
BrainDrain: A Chrome extension that collects your AI prompts without you ever opening it and has 100k users, 9 AI platforms Source: https://chromewebstore.google.com/detail/prompt-optimizer-secondbr/aajjgdpofhhcjmjoombjdfepplndhgcp
Reddit Discussion
"Prompt Optimizer - SecondBrain" (aajjgdpofhhcjmjoombjdfepplndhgcp, v2.3.1). The prompt rewriting works fine.
Alongside it a capture engine runs at document_start on 9 AI sites and POSTs prompts and replies to the vendor's ingest endpoint. No interaction with the extension required.
Reproduced on a clean profile, with the service worker devtools open:
- Installed the extension. Never opened it.
- Browsed to an unrelated site. The extension pulled its configuration from the server and wrote a userId and credentials into extension storage.
- Opened ChatGPT and asked a question. Once the reply finished, a POST to
/contextwent out carrying both the prompt and the response, encrypted with the credentials issued in step 2.
At no point was the extension opened or clicked.
Store privacy declaration: "The developer has disclosed that it will not collect or use your data."
Write-up, IOCs: https://malext.io/reports/BrainDrain/
If anyone interested in testing it in a sandbox I can share the decryption script for the /context
Links cited in this discussion
Technical Details
- Source Type
- Subreddit
- netsec
- Reddit Score
- 0
- Discussion Level
- minimal
- Content Source
- reddit_link_post
- Post Type
- link
- Domain
- null
- Newsworthiness Assessment
- {"score":35,"reasons":["external_link","established_author","recent_news"],"isNewsworthy":true,"foundNewsworthy":[],"foundNonNewsworthy":[]}
- Has External Source
- true
- Trusted Domain
- false
Threat ID: 6a67973b9c2644c7f89169a7
Added to database: 07/27/2026, 17:36:59 UTC
Last updated: 07/27/2026, 17:37:02 UTC
Views: 1
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