analyzing-network-covert-channels-in-malware
Detect and analyze covert communication channels used by malware including DNS tunneling, ICMP exfiltration, steganographic HTTP, and protocol abuse for C2 and data exfiltration.
73
67%
Does it follow best practices?
Impact
Pending
No eval scenarios have been run
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./skills/analyzing-network-covert-channels-in-malware/SKILL.mdQuality
Discovery
82%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is a strong, technically specific description that clearly identifies its domain and lists concrete detection capabilities for covert communication channels. Its main weakness is the absence of an explicit 'Use when...' clause, which would help Claude know exactly when to select this skill. The trigger terms are excellent for the cybersecurity domain.
Suggestions
Add an explicit 'Use when...' clause, e.g., 'Use when the user asks about detecting covert channels, analyzing suspicious DNS queries, investigating C2 traffic, or identifying data exfiltration techniques.'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions and techniques: DNS tunneling, ICMP exfiltration, steganographic HTTP, protocol abuse, C2, and data exfiltration. These are clearly defined capabilities. | 3 / 3 |
Completeness | Clearly answers 'what does this do' (detect and analyze covert communication channels with specific techniques listed), but lacks an explicit 'Use when...' clause or equivalent trigger guidance, which per the rubric caps completeness at 2. | 2 / 3 |
Trigger Term Quality | Includes strong natural keywords a security analyst would use: 'DNS tunneling', 'ICMP exfiltration', 'steganographic HTTP', 'C2', 'data exfiltration', 'covert communication channels', 'malware', 'protocol abuse'. Good coverage of domain-specific terms users would naturally mention. | 3 / 3 |
Distinctiveness Conflict Risk | Highly distinctive niche focused specifically on covert communication channel detection in malware analysis. The specific techniques (DNS tunneling, ICMP exfiltration, steganographic HTTP) make it very unlikely to conflict with other security or networking skills. | 3 / 3 |
Total | 11 / 12 Passed |
Implementation
52%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
The skill provides strong, executable DNS and ICMP tunneling detection code with concrete thresholds and scoring logic, making it highly actionable. However, it only covers 2 of the 4 promised covert channel types (missing HTTP steganographic and protocol abuse detection), the workflow structure is incomplete with no validation checkpoints or error recovery steps, and the overview/when-to-use sections contain boilerplate that wastes tokens.
Suggestions
Add workflow steps for HTTP covert channel and protocol abuse detection, or reference separate files for these topics to fulfill the skill's stated scope.
Add explicit validation checkpoints after each analysis step (e.g., 'Verify results by cross-referencing flagged domains against known CDN/cloud provider domains to reduce false positives').
Remove the generic 'When to Use' section and trim the overview to focus only on non-obvious information like specific detection thresholds and tool-specific quirks.
Add a feedback loop for tuning detection thresholds (e.g., 'If false positive rate > X%, adjust entropy threshold from 4.0 to 4.5 and re-run').
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The overview contains some unnecessary context (e.g., explaining what DNS tunneling, ICMP tunneling, and HTTP covert channels are at a conceptual level that Claude already knows). The 'When to Use' section is generic boilerplate. However, the code itself is reasonably efficient and the specific tool references (iodine, dnscat2, etc.) add value. | 2 / 3 |
Actionability | The skill provides fully executable Python code with concrete detection logic including entropy calculation, scoring thresholds, and specific indicators. The code is copy-paste ready with proper imports, error handling, and CLI usage. Specific numeric thresholds (entropy > 4.0, subdomain length > 30, etc.) make the guidance concrete. | 3 / 3 |
Workflow Clarity | Despite being labeled 'Step 1', there is only one step covering DNS and ICMP analysis. The description mentions HTTP covert channels and protocol abuse but provides no workflow steps for them. There are no validation checkpoints, no feedback loops for false positives, and no guidance on what to do after detection. The 'Validation Criteria' section lists expected outcomes but not how to verify them. | 1 / 3 |
Progressive Disclosure | The content has some structure with sections (Overview, Prerequisites, Workflow, Validation, References), and references are provided. However, the single large code block could benefit from being split or having advanced topics (HTTP steganography, protocol abuse detection) referenced in separate files. The skill promises coverage of four covert channel types but only delivers two inline. | 2 / 3 |
Total | 8 / 12 Passed |
Validation
90%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 10 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 10 / 11 Passed | |
- Repository
- mukul975/Anthropic-Cybersecurity-Skills
- Commit
c15f73d
- Reviewed
Table of Contents
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