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Security audit

Excalidraw Cli

Security checks across malware telemetry and agentic risk

Overview

This is a local Excalidraw diagram CLI whose main behavior matches its documentation, with bundled CI verifier scripts that should only be run on trusted folders.

Use the main excalidraw_cli.py for local diagram generation and only read/write diagram files you intend to process. Avoid running ci/verify_product.py on untrusted repositories or in environments with secrets. Prefer installing from a pinned release or this reviewed artifact instead of an unpinned GitHub main-branch curl command.

SkillSpector

By NVIDIA
Vulnerability Patterns
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
  • Output HandlingUnvalidated Output Injection, Cross-Context Output, Unbounded Output
  • Behavioral ASTexec() Call, eval() Call, Dynamic Import
  • MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
Findings (13)

subprocess module call

Medium
Category
Dangerous Code Execution
Content
def has_self_test(fp):
    r = subprocess.run([sys.executable, fp, "self-test"], capture_output=True, text=True, timeout=30)
    return r.returncode == 0 and "PASS" in r.stdout
Confidence
70% confidence
Finding
r = subprocess.run([sys.executable, fp, "self-test"], capture_output=True, text=True, timeout=30)

subprocess module call

Medium
Category
Dangerous Code Execution
Content
# 7 deploy-ready
    ci = os.path.join(os.path.dirname(os.path.abspath(__file__)), "ci_check.py")
    if os.path.isfile(ci) and os.path.isfile(skill):
        r = subprocess.run([sys.executable, ci], cwd=folder, capture_output=True, text=True)
        all_ok &= axis(r.returncode == 0, "deploy-ready (ci/ci_check.py PASS)")
    else:
        all_ok &= axis(True, "deploy-ready (skipped)")
Confidence
70% confidence
Finding
r = subprocess.run([sys.executable, ci], cwd=folder, capture_output=True, text=True)

subprocess module call

Medium
Category
Dangerous Code Execution
Content
all_ok &= axis(False, "frontmatter (no SKILL.md)")
        all_ok &= axis(False, "docs (no SKILL.md)")
    # 3 compiles
    comp_ok = all(subprocess.run([sys.executable, "-m", "py_compile", fp],
                                capture_output=True).returncode == 0 for fp in files)
    all_ok &= axis(comp_ok, "compiles (py_compile all .py)")
    # 4 self-test (any of 3 valid forms)
Confidence
70% confidence
Finding
comp_ok = all(subprocess.run([sys.executable, "-m", "py_compile", fp], capture_output=True).returncode == 0 for fp in files)

subprocess module call

Medium
Category
Dangerous Code Execution
Content
tests = [os.path.join(folder, f) for f in os.listdir(folder)
                 if (f.startswith("test_") or f.endswith("_test.py")) and f.endswith(".py")]
        if tests:
            st_ok = all(subprocess.run([sys.executable, t], capture_output=True, text=True,
                                      timeout=30).returncode == 0 for t in tests)
            st_note = f"{len(tests)} test_*.py"
        elif re.search(r"(?im)^test\s*:", skill_txt):
Confidence
70% confidence
Finding
st_ok = all(subprocess.run([sys.executable, t], capture_output=True, text=True, timeout=30).returncode == 0 for t in tests)

Lp3

Medium
Category
MCP Least Privilege
Confidence
70% confidence
Finding
Without declared permissions the skill's intent is opaque and cannot be validated.

Tp4

High
Category
MCP Tool Poisoning
Confidence
98% confidence
Finding
This is a mismatch because the declared description is narrower than the actual code behavior. The main tool does generate Excalidraw diagrams as described, but it also supports merge, info, and export operations that are not mentioned. In addition, the repository contains CI verification scripts whose purpose is package validation and security/documentation checks, which are unrelated to generating Excalidraw JSON. Under the stated criteria, unmentioned capabilities and materially unrelated code should be flagged.

Description-Behavior Mismatch

High
Confidence
99% confidence
Finding
The manifest describes a skill whose purpose is to generate Excalidraw diagram JSON, but this file implements a CI-style verifier for product folders, checking structure, frontmatter, compilation, tests, documentation, and secret patterns. Those operations are unrelated to diagram generation and represent materially different functionality than the manifest claims.

Context-Inappropriate Capability

High
Confidence
97% confidence
Finding
The verifier runs discovered Python files with a `self-test` argument and executes test files directly, allowing code execution within analyzed folders. Spawning and running arbitrary local programs is not an obvious or necessary capability for a skill whose stated purpose is generating Excalidraw JSON diagrams.

Context-Inappropriate Capability

Medium
Confidence
92% confidence
Finding
The file invokes `py_compile` on all Python files and separately executes `ci_check.py`, which are software validation and CI capabilities rather than diagram-generation logic. These behaviors are not justified by the manifest description of generating Excalidraw diagrams.

Unvalidated Output Injection

High
Category
Output Handling
Content
def has_self_test(fp):
    r = subprocess.run([sys.executable, fp, "self-test"], capture_output=True, text=True, timeout=30)
    return r.returncode == 0 and "PASS" in r.stdout
Confidence
95% confidence
Finding
subprocess.run([sys.executable, fp, "self-test"], capture_output

Unvalidated Output Injection

High
Category
Output Handling
Content
all_ok &= axis(False, "frontmatter (no SKILL.md)")
        all_ok &= axis(False, "docs (no SKILL.md)")
    # 3 compiles
    comp_ok = all(subprocess.run([sys.executable, "-m", "py_compile", fp],
                                capture_output=True).returncode == 0 for fp in files)
    all_ok &= axis(comp_ok, "compiles (py_compile all .py)")
    # 4 self-test (any of 3 valid forms)
Confidence
95% confidence
Finding
subprocess.run([sys.executable, "-m", "py_compile", fp], capture_output

Unvalidated Output Injection

High
Category
Output Handling
Content
tests = [os.path.join(folder, f) for f in os.listdir(folder)
                 if (f.startswith("test_") or f.endswith("_test.py")) and f.endswith(".py")]
        if tests:
            st_ok = all(subprocess.run([sys.executable, t], capture_output=True, text=True,
                                      timeout=30).returncode == 0 for t in tests)
            st_note = f"{len(tests)} test_*.py"
        elif re.search(r"(?im)^test\s*:", skill_txt):
Confidence
95% confidence
Finding
subprocess.run([sys.executable, t], capture_output

Unvalidated Output Injection

High
Category
Output Handling
Content
# 7 deploy-ready
    ci = os.path.join(os.path.dirname(os.path.abspath(__file__)), "ci_check.py")
    if os.path.isfile(ci) and os.path.isfile(skill):
        r = subprocess.run([sys.executable, ci], cwd=folder, capture_output=True, text=True)
        all_ok &= axis(r.returncode == 0, "deploy-ready (ci/ci_check.py PASS)")
    else:
        all_ok &= axis(True, "deploy-ready (skipped)")
Confidence
95% confidence
Finding
subprocess.run([sys.executable, ci], cwd=folder, capture_output

VirusTotal

65/65 vendors flagged this skill as clean.

View on VirusTotal

Static analysis

No suspicious patterns detected.