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Security audit

Cross Agent Mailbox

Security checks for vulnerabilities and agentic risk

Overview

This is a documentation-only skill for a local shared-file mailbox between agents, with privacy and permissions caveats but no hidden or deceptive behavior.

Use this only between trusted local agents. Set restrictive permissions on ~/.shared-mailbox, avoid putting secrets or sensitive user data in messages, validate filenames before writing or moving files, and review any cron/watchdog setup before enabling persistent checking.

SkillSpector

Vulnerability Patterns
  • Rogue AgentSelf-Modification, Session Persistence
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
Findings (4)

Missing User Warnings

Medium
Confidence
94% confidence
Finding
The README promotes a shared mailbox implemented as ordinary files in a user-accessible directory, but it does not discuss basic security properties such as file permissions, filename sanitization, race conditions, or confidentiality of messages stored in plaintext. In a multi-agent or multi-process environment, another local process can read, tamper with, overwrite, or replace mailbox files, and unsafe archiving/moving can be abused if filenames or paths are not constrained.

Missing User Warnings

Medium
Confidence
90% confidence
Finding
The skill explicitly instructs users to create and use directories under the home directory and later move files there, but it does not clearly warn that this modifies the local filesystem. In an agent skill context, undocumented filesystem writes can surprise users, create unintended persistence, and increase the chance that sensitive data is stored or manipulated without informed consent.

Missing User Warnings

Medium
Confidence
96% confidence
Finding
The mailbox design stores inter-agent messages as plaintext Markdown files on disk, yet the description does not warn users that message contents may remain readable to other local users, backups, or forensic tools. Because these messages may contain prompts, secrets, or user data, the lack of a privacy warning materially increases the risk of accidental disclosure.

Session Persistence

Medium
Category
Rogue Agent
Content
### 1. 创建信箱目录

```bash
mkdir -p ~/.shared-mailbox/{agent-a-to-b,agent-b-to-a}/{archive}
```

### 2. 创建通信协议文件
Confidence
82% confidence
Finding
The skill explicitly instructs agents to create and use a persistent shared mailbox under ~/.shared-mailbox for inter-agent communication. Persisting messages and read-status data in a user home directory can expose sensitive prompts, task data, or agent outputs to other local processes/users, and creates a durable cross-session communication channel that may bypass normal isolation expectations.

Static analysis

No suspicious patterns detected.