smtp-penetration-testing
This skill should be used when the user asks to "perform SMTP penetration testing", "enumerate email users", "test for open mail relays", "grab SMTP banners", "brute force email credentials", or "assess mail server security". It provides comprehensive techniques for testing SMTP server security.
68
82%
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Critical
Do not install without reviewing
Security
2 findings: 1 critical severity, 1 medium severity. Installing this skill is not recommended: please review these findings carefully if you do intend to do so.
E006: Malicious code pattern detected in skill scripts.
What this means
Detected high-risk code patterns in the skill content — including its prompts, tool definitions, and resources — such as data exfiltration, backdoors, remote code execution, credential theft, system compromise, supply chain attacks, and obfuscation techniques.
Why it was flagged
The document contains explicit, actionable offensive instructions (user enumeration, brute-force authentication, open-relay exploitation, header injection/spoofing and tooling) that enable deliberate malicious activity such as harvesting accounts and preparing phishing or spam campaigns.
W013: Attempt to modify system services in skill instructions.
What this means
The skill prompts the agent to compromise the security or integrity of the user’s machine by modifying system-level services or configurations, such as obtaining elevated privileges, altering startup scripts, or changing system-wide settings.
Why it was flagged
The skill explicitly instructs installing system packages using sudo (e.g., "sudo apt-get install nmap/netcat/hydra/smtp-user-enum"), which requires elevated privileges and modifies the host system state, so it should be flagged.
Low
Low-risk findings.
1 low severity finding. Worth noting, but not necessarily harmful.
W011: Third-party content exposure detected (indirect prompt injection risk).
What this means
The skill exposes the agent to untrusted, user-generated content from public third-party sources, creating a risk of indirect prompt injection. This includes browsing arbitrary URLs, reading social media posts or forum comments, and analyzing content from unknown websites.
Why it was flagged
SKILL.md instructs runtime probing of a target SMTP server (e.g., banner grabbing and relay/user testing via nmap/telnet/nc/smtp-user-enum), whose responses (outsider-authored remote service text) are then parsed and could be included in the agent’s LLM context as results/output.
- Repository
- zebbern/claude-code-guide
- Commit
af7d491
- Audited
- Security analysis
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