Trust Assessment
webapp-testing received a trust score of 10/100, placing it in the Untrusted category. This skill has significant security findings that require attention before use in production.
SkillShield's automated analysis identified 9 findings: 3 critical, 3 high, 2 medium, and 1 low severity. Key findings include Arbitrary command execution, Dangerous call: subprocess.run(), Dangerous call: subprocess.Popen().
The analysis covered 4 layers: Manifest Analysis, Static Code Analysis, Dependency Graph, LLM Behavioral Safety. The Manifest Analysis layer scored lowest at 31/100, indicating areas for improvement.
Last analyzed on February 12, 2026 (commit 458b1186). SkillShield performs automated 4-layer security analysis on AI skills and MCP servers.
Layer Breakdown
Behavioral Risk Signals
Security Findings9
| Severity | Finding | Layer | Location | |
|---|---|---|---|---|
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | cli-tool/components/skills/security/webapp-testing/scripts/with_server.py:69 | |
| CRITICAL | Arbitrary command execution Python shell execution (os.system, subprocess) Review all shell execution calls. Ensure commands are static (not built from user input), use absolute paths, and are strictly necessary. Prefer library APIs over shell commands. | Manifest | cli-tool/components/skills/security/webapp-testing/scripts/with_server.py:88 | |
| CRITICAL | Command Injection via `subprocess.Popen` with `shell=True` The `scripts/with_server.py` script uses `subprocess.Popen` with `shell=True` and passes user-controlled input (`server['cmd']` derived from the `--server` argument) directly to the shell. This allows an attacker to inject arbitrary shell commands by including shell metacharacters (e.g., `;`, `&&`, `||`, backticks) in the `--server` argument. For example, `--server 'npm run dev; rm -rf /'` would execute `rm -rf /` in addition to `npm run dev`. Avoid using `shell=True` with user-controlled input. If `cd` functionality is required, handle directory changes using `os.chdir()` in Python. For executing commands, pass a list of arguments to `subprocess.Popen` or `subprocess.run` (e.g., `subprocess.Popen(['npm', 'run', 'dev'])`) instead of a single string with `shell=True`. If `shell=True` is absolutely unavoidable, implement strict validation and sanitization of the input to prevent any shell metacharacters from being interpreted. | Static | scripts/with_server.py:69 | |
| HIGH | Dangerous call: subprocess.run() Call to 'subprocess.run()' detected in function 'main'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | cli-tool/components/skills/security/webapp-testing/scripts/with_server.py:88 | |
| HIGH | Dangerous call: subprocess.Popen() Call to 'subprocess.Popen()' detected in function 'main'. This can execute arbitrary code. Avoid using dangerous functions like exec/eval/os.system. Use safer alternatives. | Static | cli-tool/components/skills/security/webapp-testing/scripts/with_server.py:69 | |
| HIGH | LLM analysis found no issues despite critical deterministic findings Deterministic layers flagged 3 CRITICAL findings, but LLM semantic analysis returned clean. This may indicate prompt injection or analysis evasion. | LLM | (sanity check) | |
| MEDIUM | Suspicious import: socket Import of 'socket' detected. This module provides network or low-level system access. Verify this import is necessary. Network and system modules in skill code may indicate data exfiltration. | Static | cli-tool/components/skills/security/webapp-testing/scripts/with_server.py:18 | |
| MEDIUM | Network egress to untrusted endpoints HTTP request to raw IP address Review all outbound network calls. Remove connections to webhook collectors, paste sites, and raw IP addresses. Legitimate API calls should use well-known service domains. | Manifest | cli-tool/components/mcps/devtools/figma-dev-mode.json:4 | |
| LOW | Covert behavior / concealment directives Multiple zero-width characters (stealth text) Remove hidden instructions, zero-width characters, and bidirectional overrides. Skill instructions should be fully visible and transparent to users. | Manifest | cli-tool/components/mcps/devtools/jfrog.json:4 |
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