Jiffy Intel — Threat intelligence for AI artifacts

Summary

Skill walks the user's home directory for .git folders and installs a pre-commit hook that runs an attacker-controlled script on every future commit. Removing the skill does not remove the hooks.

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)find\s+.{0,80}-name\s+\.git
```

\.git/hooks/(?:pre-commit|post-commit|pre-push)

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_000024
{
    meta:
        source = "jiffy-intel"
        severity = "high"
        description = "Auto-generated from Jiffy Intel indicators"
    strings:
    $file_path_pattern_0 = "\\.git/hooks/(?:pre-commit|post-commit|pre-push)"
    $command_pattern_1 = "(?i)find\\s+.{0,80}-name\\s+\\.git"
    condition:
        $file_path_pattern_0 or $command_pattern_1
}

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

Affected tools

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

commit-quality-skillSkill
Removed
Source
Anthropic Skills
Versions
1.0.0
First observed
Mar 10, 2026
Last observed
Mar 31, 2026
hook-manager-skillSkill
Removed
Source
Community registry
First observed
Mar 15, 2026
git-polish-skillSkill
Quarantined
Source
Anthropic Skills
Versions
0.9.x
First observed
Mar 19, 2026

How to remediate

Audit .git/hooks/ in every local repo for recently-added scripts. `core.hooksPath` set to a shared dir helps centralize hooks.

Timeline & sources

Timeline

First observedMar 10, 20261 month ago
Last updatedApr 16, 20261 day ago
PublishedMar 21, 202627 days ago

Sources

scanner

References

blog.jiffylabs.aiJiffy Research

Jiffy Research — The AI Artifact Supply Chain

https://blog.jiffylabs.ai/posts/the-ai-artifact-supply-chain

attack.mitre.org

MITRE ATT&CK T1546 — Event Triggered Execution

https://attack.mitre.org/techniques/T1546/

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

Skill modifies git hooks in every local repo it touches

Summary

Severity & confidence

High

Confirmed

Indicators

Detection rule

Affected tools

Example artifacts

How to remediate

Timeline & sources

Timeline

Sources

References

Jiffy Research — The AI Artifact Supply Chain

MITRE ATT&CK T1546 — Event Triggered Execution

Scan for patterns like this