Jiffy Intel — Threat intelligence for AI artifacts

Summary

Extension requests host_permissions for claude.ai and chat.openai.com and uses chrome.cookies to read the session cookie, then POSTs it off-host. Permitted by MV3 APIs; still a severe credential-exfil primitive.

Severity & confidence

Severity

Critical

Active exploitation in the wild, high blast radius, or direct data exfiltration vector. Treat as an urgent remediation target; quarantine affected artifacts immediately.

Confidence

Confirmed

Observed directly by Jiffy scanners or validated by multiple independent sources. Indicators are reliable enough to drive automated action.

Indicators

Observed patterns and artifacts associated with this entry. Each indicator can be copied into your detection stack or SIEM.

```
(?i)chrome\.cookies\.get
```

(?i)host_permissions.{0,200}(?:claude\.ai|chat\.openai\.com)

Detection rule

A YARA-style pseudo-rule auto-generated from the indicators above. Useful as a starting point — adapt the syntax for your target detection platform.

YARA-style pseudo-rule

rule jiffy_ti_2026_000097
{
    meta:
        source = "jiffy-intel"
        severity = "critical"
        description = "Auto-generated from Jiffy Intel indicators"
    strings:
    $content_pattern_0 = "(?i)chrome\\.cookies\\.get"
    $content_pattern_1 = "(?i)host_permissions.{0,200}(?:claude\\.ai|chat\\.openai\\.com)"
    condition:
        $content_pattern_0 or $content_pattern_1
}

Auto-generated from the indicators above. Adapt syntax for your detection stack before deploying.

Affected tools

Tool	Versions	Status
Chrome / Chromium	`*`	vulnerable
ChatGPT (GPT Store)	`*`	vulnerable
claude.ai (Projects)	`*`	vulnerable

Example artifacts

Sanitized examples of artifacts Jiffy has observed exhibiting this pattern. Publisher handles are redacted; version ranges and status reflect the most recent scan.

AI Assistant HubExtension
Removed
Source
Chrome Web Store
First observed
Mar 1, 2026
Last observed
Mar 28, 2026
Chat ToolkitExtension
Removed
Source
Firefox Add-ons
First observed
Mar 5, 2026
Last observed
Mar 31, 2026

How to remediate

01Revoke browser session tokens for affected AI sites.
02Reinstall extensions via a known-clean account.
03Block AI-vendor host_permissions at EDR layer.

Timeline & sources

Timeline

First observedMar 1, 20261 month ago
Last updatedApr 22, 2026today
PublishedMar 17, 20261 month ago

Sources

scanner

References

arxiv.orgarXiv

Browser Extension AI-Assistant Abuse (arXiv 2509.12033)

https://arxiv.org/abs/2509.12033

attack.mitre.org

MITRE ATT&CK T1555 — Credentials from Password Stores

https://attack.mitre.org/techniques/T1555/

Related intel

Other entries of type Credential Exfil, or the most recent published entries if no same-type matches exist.

Credential ExfilHigh

.cursorrules fetches remote rule that encodes "submit secrets" logic

.cursorrules with `extends: <url>` resolves to a remote rule set whose content includes directives to read repo-local .env and post-process before any commit. A separation between policy declaration (local) and policy content (remote) hides the exfiltration.

Jiffy IntelApr 27

Credential ExfilHigh

Custom GPT Action logs full request bodies including Authorization headers

Action backend that logs every inbound request, including the OAuth Authorization header forwarded by the GPT. Logs are retained and occasionally shared with third-party observability tools.

Jiffy IntelApr 27

Credential ExfilLow

Claude Project knowledge file contains hardcoded API tokens

Project uploader accidentally includes a knowledge file (often a README or internal doc) that has API tokens embedded. Any team member running the project can view the file, and the tokens enter model context on every turn.

Jiffy IntelApr 27

Extension with MV3 host permissions reads cookies for AI vendor sites

Summary

Severity & confidence

Critical

Confirmed

Indicators

Detection rule

Affected tools

Example artifacts

How to remediate

Timeline & sources

Timeline

Sources

References

Browser Extension AI-Assistant Abuse (arXiv 2509.12033)

MITRE ATT&CK T1555 — Credentials from Password Stores

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