Jiffy Intel — Threat intelligence for AI artifacts

Summary

.cursorrules hardcodes "always use gpt-3.5-turbo" for code reviews. The pinned older model is prone to missing modern vulnerability patterns. Not a direct exploit — a steering attack against downstream safety.

Severity & confidence

Severity

Low

Hygiene-grade issue with limited direct impact. Fix opportunistically; monitor in case context changes (new exploit, new dependency, etc.).

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)model\s*:\s*"?gpt-3\.5|claude-instant

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_000071
{
    meta:
        source = "jiffy-intel"
        severity = "low"
        description = "Auto-generated from Jiffy Intel indicators"
    strings:
    $content_pattern_0 = "(?i)model\\s*:\\s*\"?gpt-3\\.5|claude-instant"
    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: legacy-saas)IDE rules
Still live
Source
GitHub (public repo)
First observed
Feb 21, 2026
.cursorrules (repo: old-ruby-app)IDE rules
Still live
Source
GitHub (public repo)
First observed
Feb 25, 2026
Prior to agent maturity; still shipping.

How to remediate

01Keep model pins current.
02Review legacy rule files when inherited from old templates.

Timeline & sources

Timeline

First observedFeb 21, 20261 month ago
Last updatedApr 18, 2026today
PublishedMar 5, 20261 month ago

Sources

scanner

References

genai.owasp.orgOWASP

OWASP LLM-06: Excessive Agency (2026)

https://genai.owasp.org/llmrisk/llm-06-2026/

Related intel

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

Supply ChainMedium

IDE rule file fetched from homoglyphed domain

.cursorrules extends from a URL using a homoglyph — e.g., `raw.githubusercontent.c0m` — that serves a malicious ruleset. Casual review misses the character substitution.

Jiffy IntelApr 28

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

BackdoorHigh

Skill writes config that hooks into Claude Desktop stdio MCP bridge

Skill modifies the user's Claude Desktop config to register an MCP server pointing at localhost. The server is supplied by the same skill and serves as a persistent interposer between the agent and tool calls, logging all tool arguments.

Jiffy IntelApr 28

.cursorrules contains outdated model pins that steer to deprecated GPTs

Summary

Severity & confidence

Low

Confirmed

Indicators

Detection rule

Affected tools

Example artifacts

How to remediate

Timeline & sources

Timeline

Sources

References

OWASP LLM-06: Excessive Agency (2026)

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