registry / AI-agent capability abuse / pennyrouter / 0.3.4

pennyrouter@0.3.4

Install and manage PennyRouter local coding-agent integrations.

AI Security Review

scanned 2mo ago · by lpm-firewall-ai

This is an explicit-user-command agent integration, not an install-time attack. Its unpinned npx persistence and agent-control-surface changes are a concrete ongoing risk, so it should be warned rather than blocked.

Static reason

One or more suspicious static signals were detected.; previous stored version diff introduced dangerous source

Trigger

A user runs pennyrouter install or update, then the configured agent starts its MCP server.

Impact

A future registry release of the same package can gain execution in the configured agent context.

Mechanism

Agent-config registration with an unpinned npx command.

AI rationale

Evidence

src/cli.jssrc/mcp-register.jssrc/statusline.js~/.claude.json~/.codex/config.toml~/.claude/settings.json

Network endpoints1

api.pennyrouter.com

Decision evidence

public snapshot

AI called this Suspicious at 91.0% confidence as Dangerous Capability with low false-positive risk.

Evidence for warning

The install and update flows register an MCP server in existing Claude Code and Codex configuration.
That MCP entry runs an unpinned `npx -y pennyrouter mcp`, allowing a later registry release to execute when the agent starts it.
The Claude status-line integration replaces the configured command and executes a previously configured command through a shell.
The CLI sends user-supplied upstream credentials to the selected gateway.

Evidence against

package.json has no preinstall, install, or postinstall lifecycle hook.
The configuration changes occur only after the user runs the CLI install or update command.
MCP writers back up existing files and avoid overwriting an unrelated server with the same name.
The CodeGPT harness only provides manual instructions and clipboard support.

Behavioral surface

Source

ChildProcessCryptoEnvironmentVarsFilesystemNetworkShell

Supply chain

Source & flagged code

6 flagged

src/launch.test.jsView file

1import assert from "node:assert/strict"; L2: import { spawnSync } from "node:child_process"; L3: import fs from "node:fs"; ... L39: async function main() { L40: if (!(["darwin", "linux"].includes(process.platform))) { L41: console.log("launch.test.js: skipped on unsupported platform"); ... L45: const root = fs.mkdtempSync(path.join(os.tmpdir(), "pr-launch-test-")); L46: const previous = Object.fromEntries(ENV_KEYS.map((key) => [key, process.env[key]])); L47: const home = path.join(root, "home"); ... L53: }, null, 2)}\n`; L54: const nativeCodex = 'model = "native-model"\n\nmodel_provider = "pennyrouter"\n\n[model_providers.pennyrouter]\nname = "PennyRouter"\nbase_url = "http://localhost:8400/v1"\n'; L55: fs.writeFileSync(path.join(home, ".claude", "settings.json"), nativeClaude);

Medium

Install Persistence

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

src/launch.test.jsView on unpkg · L1

src/harnesses/codegpt.jsView file

1import { spawnSync } from "node:child_process"; L2: ... L56: console.log(" Open CodeGPT settings and remove or replace the PennyRouter provider:"); L57: console.log(" - Base URL: https://api.pennyrouter.com/v1"); L58: console.log(" - API Key: pr-..."); ... L64: const commands = L65: process.platform === "darwin" L66: ? [["pbcopy"]] L67: : process.platform === "win32"

High

Sandbox Evasion Gated Capability

Source gates dangerous network, credential, or execution behavior behind CI, host, platform, time, or geo fingerprint checks.

src/harnesses/codegpt.jsView on unpkg · L1

src/statusline.jsView file

•Runtime or CLI code links a write operation to an explicit external AI-agent control path: code (installed by \`pennyrouter install\`). // prints: [wrapped original statusline (all lines) |] penny segment (penny / penny (sub) // / penny (byok) / penny off). the wrapped statusline's first line gets the penny suffix; // any further lines (e.g. a context bar) pass through verbatim. // never blocks on the network: reads a per-session cache and refreshes it detached. import { readfilesync, mkdirsync, writefilesync, statsync } from "node:fs"; import { spawn, spawnsync } from "node:child_process"; import { join, basename } from "node:path"; import os from "node:os"; const statedir = join( process.env.xdg_state_home || join(os.homedir(), ".local", "state"), "pennyrouter", ); const cachedir =

High

External Ai Agent Control Surface Mutation

Runtime or CLI source writes behavior-bearing configuration into a user or project AI-agent control surface.

src/statusline.jsView on unpkg

src/launch.jsView file

•Manifest-trigger-reachable source links an external AI-agent control path to a behavior-bearing write operation. "# <<< pennyrouter path <<<"; const codex_profile_marker = "# pennyrouter per-command profile (managed; no secrets)"; const claude_command_marker = ""; const claude_desktop_profile_id = "70656e6e-7972-4f75-8465-720000000001"; const claude_desktop_profile_name = "pennyrouter"; const terminal_title_refresh_ms = 1000; const terminal_status_refresh_ms = 15000; export function pennyconfigdir() { if (process.platform === "win32") { return join(process.env.appdata || process

High

Trigger Reachable External Ai Agent Control Surface Mutation

Manifest-trigger-reachable source writes behavior-bearing configuration into a user or project AI-agent control surface.

src/launch.jsView on unpkg

•matchType = previous_version_dangerous_delta matchedPackage = pennyrouter@0.3.3 matchedIdentity = npm:cGVubnlyb3V0ZXI:0.3.3 similarity = 0.903 summary = stored previous version shares package body but lacks this dangerous source file

High

Previous Version Dangerous Delta

This package version adds a dangerous source file absent from the previous stored version; route for source-aware review.

src/launch.jsView on unpkg

src/mcp-register.js#virtual:normalized:round1View file

•stage = ast_semantic_analysis; reason = ast_parse_error; limitedFiles = 3

High

Semantic Analysis Limited

A bounded semantic-analysis stage reached its safety limit; remaining detectors completed, but this package requires AI review.

src/mcp-register.js#virtual:normalized:round1View on unpkg

Source & flagged code

6 flagged · loading source

src/launch.test.jsView file

Medium

Install Persistence

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

src/launch.test.jsView on unpkg · L1

src/harnesses/codegpt.jsView file

High

Findings

5 High4 Medium4 Low

HighSandbox Evasion Gated Capabilitysrc/harnesses/codegpt.js

HighExternal Ai Agent Control Surface Mutationsrc/statusline.js

HighTrigger Reachable External Ai Agent Control Surface Mutationsrc/launch.js

HighSemantic Analysis Limitedsrc/mcp-register.js#virtual:normalized:round1

HighPrevious Version Dangerous Deltasrc/launch.js

MediumNetwork

MediumEnvironment Vars

MediumInstall Persistencesrc/launch.test.js

MediumStructural Risk Force Deep Review

LowScripts Present

LowFilesystem

LowHigh Entropy Strings

LowUrl Strings

Affected versions and remediation

This report applies to pennyrouter@0.3.4.

See all versions of pennyrouter for other recorded verdicts.

Review the evidence and your use of pennyrouter@0.3.4 before allowing it. Restrict the permissions described in this report.
Choose an independently verified alternative or release. This report does not establish that other versions are safe.

Evidence last updated: 2026-09-04 20:33:48.482Z (UTC).

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