postboi@0.56.0
Postboi is an email provider and TypeScript SDK. Send email with one token and no DNS setup, plus SMS, WhatsApp, push and chat from the same API. You can also use your own provider (Resend, SES, Postmark and more) if you want to.
AI Security Review
scanned 1mo ago · by lpm-firewall-aiThe source shows first-party agent extension setup with automatic refresh and dependency-linked instructions, warranting a lifecycle warning under the supplied policy. Explicit CLI activation and the absence of npm install hooks do not support a malicious publish block.
Static reason
High-risk behavior combination matched malicious policy.
Trigger
Running postboi skill or postboi init; --agent setup accepts confirmation defaults automatically.
Impact
Later package releases can change instructions consumed by coding agents. The inspected behavior does not establish malicious control hijacking.
Mechanism
Setup links or copies bundled skills, adds companion agent files, and appends an instruction pointer. Existing skills refresh without renewed consent, and linked skills follow dependency upgrades.
AI rationale
The source shows first-party agent extension setup with automatic refresh and dependency-linked instructions, warranting a lifecycle warning under the supplied policy. Explicit CLI activation and the absence of npm install hooks do not support a malicious publish block.
Evidence
dist/cli.js.claude/skills/postboi/SKILL.md.agents/skills/postboi/SKILL.mdAGENTS.md
Decision evidence
public snapshotAI called this Suspicious at 94.0% confidence as Dangerous Capability with medium false-positive risk.
Evidence for warning
- The CLI installs Postboi skills in .claude and .agents and appends a pointer to an existing AGENTS.md.
- Interactive setup asks before initial skill installation, but refreshes existing skills without another prompt.
- The explicit --agent setup mode automatically accepts confirmation defaults.
- Skills can link to the installed dependency, allowing package upgrades to change agent instructions.
- Agent setup is reached through explicit CLI commands; package.json has no preinstall, install, or postinstall hook.
Evidence against
- No concrete malicious attack was established in the inspected source.
- The integration uses package-owned skill locations and provides an interactive installation prompt.
Behavioral surface
ChildProcessCryptoDynamicRequireEnvironmentVarsFilesystemNetworkShell
HighEntropyStringsMinified
Source & flagged code
6 flaggeddist/cli.jsView file
41// src/library/encoding.ts
L42: function base64_decode(value) {
L43: const binary = atob(value);
...
L125: const { pathToFileURL } = await import("node:url");
L126: let dir = process.cwd();
L127: for (;; ) {
...
L270: if (this.#hooks.before?.send) {
L271: return this.#hooks.before.send({
L272: provider: this.provider,
...
L319: async send_request(url, init) {
L320: return fetch(url, init);
L321: }
Critical
Credential Exfiltration
Source appears to send environment or credential material to an external endpoint.
dist/cli.jsView on unpkg · L4141// src/library/encoding.ts
L42: function base64_decode(value) {
L43: const binary = atob(value);
...
L125: const { pathToFileURL } = await import("node:url");
L126: let dir = process.cwd();
L127: for (;; ) {
...
L270: if (this.#hooks.before?.send) {
L271: return this.#hooks.before.send({
L272: provider: this.provider,
...
L319: async send_request(url, init) {
L320: return fetch(url, init);
L321: }
Critical
Browser Credential Phishing
Source appears to collect browser login credentials for exfiltration.
dist/cli.jsView on unpkg · L41791} from "node:fs";
L792: import { spawnSync } from "node:child_process";
L793: import { join as join7, delimiter, dirname as dirname4 } from "node:path";
Findings
2 Critical3 High4 Medium5 Low
CriticalCredential Exfiltrationdist/cli.js
CriticalBrowser Credential Phishingdist/cli.js
HighChild Processdist/cli.js
HighShelldist/cli.js
HighCommand Output Exfiltrationdist/cli.js
MediumDynamic Requiredist/workers_env.js
MediumNetwork
MediumEnvironment Vars
MediumStructural Risk Force Deep Review
LowNon Install Lifecycle Scripts
LowScripts Present
LowFilesystem
LowHigh Entropy Strings
LowUrl Strings
Affected versions and remediation
This report applies to postboi@0.56.0.
See all versions of postboi for other recorded verdicts.
- Review the evidence and your use of postboi@0.56.0 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: .
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