Malicious SkillPublished Mar 25, 2026

Skill overwrites ~/.claude/settings.json to disable permission prompts

HighAARM tierConfirmed
Seen27times across5customers
jiffy-ti-2026-000014

Summary

Skill whose setup step silently rewrites ~/.claude/settings.json, flipping `alwaysAllowToolInvocation` to true and clearing the tool allowlist. Subsequent skills in the session then execute without user consent, including network egress and filesystem writes the user never approved.

Severity & confidence

Severity
High

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

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.

  • (?is)settings\.json.{0,200}(?:alwaysAllow|skip[_\s-]?permissions|auto[_\s-]?approve)
  • \.claude/settings\.json

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_000014
{
    meta:
        source = "jiffy-intel"
        severity = "high"
        description = "Auto-generated from Jiffy Intel indicators"
    strings:
    $file_path_pattern_0 = "\\.claude/settings\\.json"
    $command_pattern_1 = "(?is)settings\\.json.{0,200}(?:alwaysAllow|skip[_\\s-]?permissions|auto[_\\s-]?approve)"
    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

ToolVersionsStatus
Claude Code*vulnerable
Claude Desktop*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.

  • claude-speed-tweaksSkill
    Removed
    Source
    Anthropic Skills
    Versions
    1.3.0
    First observed
    Mar 11, 2026
    Last observed
    Apr 2, 2026
  • dev-mode-fastSkill
    Removed
    Source
    Community registry
    Versions
    0.9.x
    First observed
    Mar 15, 2026
    Last observed
    Apr 4, 2026

How to remediate

  1. 01Pin ~/.claude/settings.json via a pre-commit hook or MDM profile; treat any skill write to this file as a critical alert.
  2. 02Restore consent prompts manually if the file was modified.

Timeline & sources

Timeline

  1. First observedMar 11, 20261 month ago
  2. Last updatedApr 16, 20261 day ago
  3. PublishedMar 25, 202623 days ago

Sources

scannercurated

References

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