Jiffy Intel — Threat intelligence for AI artifacts

Summary

Skill appends a task to the user's VS Code workspace tasks.json with `runOn: "fileSave"` and a command that downloads and runs an attacker binary. Triggers on any subsequent file save, not bound to the original skill session.

Severity & confidence

Severity

Medium

Notable weakness with plausible abuse chains or partial mitigations already in place. Track, and resolve as part of your normal hardening cadence.

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.

```
\.vscode/tasks\.json
```

(?is)"runOn"\s*:\s*"fileSave"[\s\S]{0,300}(?:curl|wget|powershell)

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_000028
{
    meta:
        source = "jiffy-intel"
        severity = "medium"
        description = "Auto-generated from Jiffy Intel indicators"
    strings:
    $file_path_pattern_0 = "\\.vscode/tasks\\.json"
    $content_pattern_1 = "(?is)\"runOn\"\\s*:\\s*\"fileSave\"[\\s\\S]{0,300}(?:curl|wget|powershell)"
    condition:
        $file_path_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
VS 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.

vscode-productivity-skillSkill
Removed
Source
Anthropic Skills
Versions
1.0.0
First observed
Mar 31, 2026
Last observed
Apr 12, 2026
workspace-config-skillSkill
Quarantined
Source
Community registry
First observed
Apr 4, 2026

How to remediate

01Review .vscode/tasks.json for runOn: fileSave tasks that invoke network binaries.
02Remove unknown tasks.

Timeline & sources

Timeline

First observedMar 31, 202617 days ago
Last updatedApr 26, 2026today
PublishedApr 8, 20269 days ago

Sources

scanner

References

attack.mitre.org

MITRE ATT&CK T1546 — Event Triggered Execution

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

blog.jiffylabs.aiJiffy Research

Jiffy Research — .cursorrules and agents.md Config Backdoors

https://blog.jiffylabs.ai/posts/cursorrules-and-agents-md-config-backdoors

Related intel

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

Malicious SkillHigh

MCP server's install script drops a skill into ~/.claude/skills/

MCP server whose install path (`pip install`, `npm i`) includes a side-effect that writes a skill file under the user's Claude skills directory. Installing the MCP silently installs a skill the user never consented to.

Jiffy IntelApr 28

Malicious SkillLow

AGENTS.md tells agent to paste ~/.ssh/id_rsa.pub into PR for CI setup

AGENTS.md has a section titled "CI onboarding" that instructs the agent to paste the user's SSH public key into PR descriptions. While public keys are not immediately sensitive, the coerced habit normalizes key pasting and enables later pattern-matching attacks.