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.
The description excels at specificity and distinctiveness, listing concrete techniques and domain-specific terminology that security professionals would naturally use. Its main weakness is the absence of an explicit 'Use when...' clause, which would help Claude know exactly when to select this skill. Adding trigger guidance would elevate this from a good to excellent description.
Suggestions
Add a 'Use when...' clause such as 'Use when investigating suspicious network traffic, analyzing malware communication patterns, or when the user mentions DNS tunneling, C2 channels, data exfiltration, or covert protocols.'
Consider adding common user-facing variations like 'command and control' (spelled out), 'beaconing', or 'network-based indicators of compromise' to broaden trigger coverage.
| 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 caps this at 2 per the rubric. | 2 / 3 |
Trigger Term Quality | Includes strong natural keywords a security analyst would use: 'DNS tunneling', 'ICMP exfiltration', 'steganographic HTTP', 'protocol abuse', 'C2', 'data exfiltration', 'covert communication channels', 'malware'. These are terms professionals naturally use when investigating these threats. | 3 / 3 |
Distinctiveness Conflict Risk | Highly specific niche focused on covert channel detection in malware analysis. The combination of DNS tunneling, ICMP exfiltration, steganography, and C2 protocol abuse is very distinct and unlikely to conflict with other 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 well-chosen thresholds and scoring logic, making it highly actionable. However, it falls short on workflow clarity—there's no multi-step process, no validation checkpoints, and no guidance on interpreting or acting on results. The scope promised in the description (HTTP steganographic channels, protocol abuse) is largely undelivered, and the overview/when-to-use sections contain boilerplate that wastes tokens.
Suggestions
Add explicit workflow steps for what to do after detection: triaging results, filtering false positives (CDN/cloud domains), and escalation procedures with validation checkpoints.
Implement the promised HTTP covert channel and protocol abuse detection, either inline or via clearly referenced separate files.
Remove the generic 'When to Use' section and trim the overview to focus on detection-specific knowledge Claude wouldn't already have (e.g., specific thresholds, tool-specific signatures, known malware family patterns).
Add a validation/verification step such as testing against a known-good PCAP with labeled tunneling traffic to confirm detection accuracy before trusting results.
| 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 detection thresholds and scoring logic add genuine value. | 2 / 3 |
Actionability | The skill provides fully executable Python code with concrete detection logic, specific thresholds (entropy > 4.0, subdomain length > 30, unique ratio > 0.9), scoring mechanisms, and CLI usage. The code is copy-paste ready and handles both DNS and ICMP tunneling detection with clear output formatting. | 3 / 3 |
Workflow Clarity | Despite being labeled 'Step 1', there is only one step covering DNS tunneling detection (with ICMP bundled in the same script). The title mentions HTTP steganographic channels and protocol abuse but these are never addressed. There are no validation checkpoints, no feedback loops for false positives, and no guidance on what to do after detection results are produced. The 'Validation Criteria' section lists expected outcomes but provides no actual validation steps. | 1 / 3 |
Progressive Disclosure | The content has some structure with sections (Overview, Prerequisites, Workflow, Validation, References), and references to external resources are provided. However, the single large code block could benefit from being split or having the HTTP/steganographic analysis in a referenced file. The skill promises coverage of HTTP covert channels and protocol abuse in the description but doesn't deliver or point to where that content lives. | 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
888bbe4
- Reviewed
Table of Contents
Is this your skill?
If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.