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bumper-guard@0.2.1: Malicious npm security report (Block) | LPM Firewall

registry / bumper-guard / 0.2.1

bumper-guard@0.2.1

A plain-language safety net for vibe coders. Pauses risky things your AI assistant (Claude Code, Cursor, Codex CLI, Copilot CLI) is about to do, explains them in plain English, and lets you decide.

AI Security Review

scanned 2h ago · by lpm-firewall-ai

Installation silently changes global AI-agent control settings and establishes a persistent background daemon. The installed hooks can observe agent tool requests.

Static reason

One or more suspicious static signals were detected.

Trigger

npm postinstall during package installation when matching agent directories exist.

Impact

It can alter approval behavior across Claude Code, Cursor, Copilot, and Codex without an explicit setup command, then persist after login.

Mechanism

Automatic global hook injection and per-user daemon persistence.

Attack narrative

Installing the package invokes postinstall automatically. It finds agent configuration directories, injects global pre-tool hooks or Codex approval settings, starts its daemon detached, and registers a user-login startup mechanism. The resulting hooks receive agent commands, file paths, and content and forward them to the daemon. Although the inspected forwarding is local and no remote exfiltration of those fields was found, the unprompted lifecycle mutation of multiple foreign AI-agent control surfaces and persistence is concrete.

Rationale

This is malicious under the firewall policy because an npm postinstall automatically modifies broad, foreign AI-agent control surfaces and creates persistence. The local-only command handling reduces data-theft evidence but does not negate the unconsented install-time behavior.

Evidence

package.jsonsrc/installers/postinstall.jssrc/installers/claude-code.jssrc/installers/cursor.jssrc/installers/copilot.jssrc/installers/codex.jssrc/installers/autostart.js

Source & flagged code

4 flagged · loading source

package.jsonView file

•scripts.postinstall = node src/installers/postinstall.js || true

High

Install Time Lifecycle Scripts

Package defines install-time lifecycle scripts.

package.jsonView on unpkg

•scripts.postinstall = node src/installers/postinstall.js || true

Medium

Ambiguous Install Lifecycle Script

Install-time lifecycle script is not statically allowlisted and needs review.

package.jsonView on unpkg

src/installers/autostart.jsView file

3Trigger-reachable persistence chain: scripts.postinstall -> src/installers/postinstall.js -> src/installers/autostart.js L3: const path = require("path"); L4: const { execFileSync } = require("child_process"); L5: ... L10: L11: const BIN_PATH = path.join(__dirname, "..", "..", "bin", "bumper.js"); L12: const LAUNCH_AGENT_LABEL = "com.bumper.autostart"; ... L26: const WIN_STARTUP_DIR = () => L27: path.join(process.env.APPDATA || path.join(os.homedir(), "AppData", "Roaming"), "Microsoft", "Windows", "Start Menu", "Programs", "Startup"); L28: const WIN_LAUNCHER_PATH = () => path.join(WIN_STARTUP_DIR(), "BumperAutostart.vbs"); ... L79: fs.writeFileSync(LAUNCH_AGENT_PATH, plistContents()); L80: run("launchctl", ["load", "-w", LAUNCH_AGENT_PATH]); L81: return { platform: "darwin", mechanism: "

High

Trigger Reachable Persistence

A manifest entrypoint or package-local install chain reaches persistence behavior.

src/installers/autostart.jsView on unpkg · L3

3const path = require("path"); L4: const { execFileSync } = require("child_process"); L5: ... L10: L11: const BIN_PATH = path.join(__dirname, "..", "..", "bin", "bumper.js"); L12: const LAUNCH_AGENT_LABEL = "com.bumper.autostart"; ... L26: const WIN_STARTUP_DIR = () => L27: path.join(process.env.APPDATA || path.join(os.homedir(), "AppData", "Roaming"), "Microsoft", "Windows", "Start Menu", "Programs", "Startup"); L28: const WIN_LAUNCHER_PATH = () => path.join(WIN_STARTUP_DIR(), "BumperAutostart.vbs"); ... L79: fs.writeFileSync(LAUNCH_AGENT_PATH, plistContents()); L80: run("launchctl", ["load", "-w", LAUNCH_AGENT_PATH]); L81: return { platform: "darwin", mechanism: "launchd LaunchAgent", ref: LAUNCH_AGENT_PATH };

Medium

Install Persistence

Source writes installer persistence such as shell profile or service configuration.

src/installers/autostart.jsView on unpkg · L3