Jiffy Intel — Threat intelligence for AI artifacts

Summary

.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.

Severity & confidence

Severity

High

Credible abuse path with meaningful impact on confidentiality, integrity, or availability. Remediate on a short timeline; do not wait for the next sprint cycle.

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)extends\s*:\s*https?://
```

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_000069
{
    meta:
        source = "jiffy-intel"
        severity = "high"
        description = "Auto-generated from Jiffy Intel indicators"
    strings:
    $content_pattern_0 = "(?i)extends\\s*:\\s*https?://"
    condition:
        $content_pattern_0
}

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

Affected tools

Tool	Versions	Status
Cursor	`*`	vulnerable
Claude Code	`*`	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.

.cursorrules (repo: sass-pro-starter)IDE rules
Removed
Source
GitHub (public repo)
First observed
Mar 19, 2026
Last observed
Apr 12, 2026
.cursorrules (repo: marketing-site-kit)IDE rules
Under review
Source
GitHub (public repo)
First observed
Mar 23, 2026

How to remediate

01Prohibit remote `extends` URLs.
02All IDE rule content must live in-repo and be reviewable at commit time.

Timeline & sources

Timeline

First observedMar 19, 202629 days ago
Last updatedApr 27, 2026today
PublishedMar 27, 202621 days ago

Sources

scanner

References

blog.jiffylabs.aiJiffy Research

Related intel

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

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

OtherLow

.cursorrules contains large wall-of-text that pushes user intent out of context

.cursorrules whose rule body exceeds 20 000 characters of filler content. Each agent invocation consumes the rule, leaving limited context for the user prompt. Not a direct exfiltration primitive — a budget-starvation attack.

Jiffy IntelApr 28

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