analyzing-powershell-script-block-logging
Parse Windows PowerShell Script Block Logs (Event ID 4104) from EVTX files to detect obfuscated commands, encoded payloads, and living-off-the-land techniques. Uses python-evtx to extract and reconstruct multi-block scripts, applies entropy analysis and pattern matching for Base64-encoded commands, Invoke-Expression abuse, download cradles, and AMSI bypass attempts.
55
62%
Does it follow best practices?
Impact
—
No eval scenarios have been run
Risky
Do not use without reviewing
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/analyzing-powershell-script-block-logging/SKILL.mdSecurity
2 findings — 1 high severity, 1 medium severity. You should review these findings carefully before considering using this skill.
W007: Insecure credential handling detected in skill instructions
What this means
The skill handles credentials insecurely by requiring the agent to include secret values verbatim in its generated output. This exposes credentials in the agent’s context and conversation history, creating a risk of data exfiltration.
Why it was flagged
Insecure credential handling detected (high risk: 0.80). The prompt requires reconstructing and reporting full PowerShell script blocks from event logs, which can include sensitive secrets (passwords, tokens, keys) and therefore would force the agent to handle/output secret values verbatim.
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
Third-party content exposure detected (high risk: 0.70). The runtime path reads OUTSIDER-authored free text from the user-supplied EVTX file (`--evtx-file`), parses Event 4104 `ScriptBlockText`/`MessageNumber`/etc. as XML text, reconstructs it, and then feeds the reconstructed `script_text` into the LLM context (via any downstream LLM step); since the EVTX contents are not authored by the operating user, this is outsider-provided log content.
- Repository
- mukul975/Anthropic-Cybersecurity-Skills
- Commit
0445030
- Audited
- Security analysis
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