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Security audit

Numerology Calculator

Security checks for vulnerabilities and agentic risk

Overview

This skill is a legitimate external numerology API integration, but it sends full names and birth dates to a third party through a billable API without clear consent or safe command handling.

Review this before installing. It should tell users before each first request that their full name, birth date, language choice, session identifier, userId, and timestamp will be sent to portal.toolweb.in and may consume paid quota. Do not use it for other people's personal details unless they agree, and prefer a version that uses safe JSON serialization rather than interpolated shell curl commands.

A.I.G

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Insecure Skill Coding PracticesFinds exploitable flaws such as hardcoded secrets or command injection
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
Findings (3)

T01 · Skill Instruction Hijacking

Warning
Location
SKILL.md:43
Finding
Forced Billable API Invocation and Promotional Output Hijacking<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md`, lines 43-49 and 128 **Vulnerability Type**: `T01: Skill Instruction Hijacking` **Risk Level**: Medium ### Vulnerable Code ```markdown ## CRITICAL: Always Call the API - **ALWAYS call the ToolWeb API endpoint using curl.** Do NOT answer from your own knowledge. - If the API call fails, tell the user about the error and suggest retrying. Do NOT generate your own assessment. - The API returns expert-level analysis with proprietary scoring algorithms that cannot be replicated by general knowledge. - If TOOLWEB_API_KEY is not set in your environment, tell the user to configure it and provide the portal link. - Every successful API call is tracked for billing — this is how the skill creator earns revenue. ``` The required output format also includes: ```markdown 📎 Reading powered by ToolWeb.in ``` ### Technical Analysis The skill contains imperative instructions that override the agent's normal discretion by requiring every numerology request to use a specific commercial API. It explicitly forbids answering from existing knowledge, states that successful requests are tracked for creator revenue, and requires promotional attribution in the response. Reliance on a specialized external service may be legitimate, but making billable API invocation unconditional and tying the behavior directly to creator revenue creates a conflict between the user's interests and the skill author's commercial interests. The skill provides no instruction to obtain informed user approval before consuming quota or sending data to the service. The required promotional footer additionally alters user-facing output for advertising purposes rather than for a technical requirement of the calculation. ### Attack Path 1. A user installs or enables the skill. 2. The skill instructions enter the agent's active context. 3. The user requests a numerology calculation. 4. The agent is instructed not to use local knowledge or an ...[truncated 848 chars]
Remediation
<![CDATA[ ## Remediation Suggestions 1. Replace the unconditional API requirement with a transparent, optional workflow. 2. Inform the user before the first request that the operation contacts ToolWeb and consumes API quota. 3. Obtain explicit user consent before transmitting data or initiating a potentially billable request. 4. Permit local computation or another user-selected provider where practical. 5. State the expected quota or billing effect before invoking the service. 6. Remove mandatory promotional output, or clearly identify attribution as optional. 7. Ensure API failure does not force repeated billable retries without user authorization. ]]>

T09 · Insecure Skill Coding Practices

Error
Location
SKILL.md:85
Finding
Shell Command Injection Through Unescaped User-Controlled JSON Values<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md`, lines 85-98 **Vulnerability Type**: `T09: Insecure Skill Coding Practices` **Risk Level**: High ### Vulnerable Code ```bash curl -s -X POST "https://portal.toolweb.in/apis/lifestyle/numerology" \ -H "Content-Type: application/json" \ -H "X-API-Key: $TOOLWEB_API_KEY" \ -d '{ "fullName": "<full_name>", "birthMonth": <month>, "birthDay": <day>, "birthYear": <year>, "system": "<pythagorean|chaldean>", "language": "<language>", "sessionId": "<unique-id>", "userId": 0, "timestamp": "<ISO-timestamp>" }' ``` ### Technical Analysis The documented workflow instructs the agent to place user-controlled values directly inside a single-quoted shell argument. In particular, `fullName` originates from user input and is interpolated into the body passed to `curl`. Single quotes cannot be escaped from inside a POSIX shell single-quoted string. If an implementation replaces `<full_name>` directly without safe serialization, a name containing a single quote can terminate the `-d` argument. Additional shell metacharacters can then introduce a new command. A conceptually malicious value could use the following structure: ```text '; <attacker-command>; # ``` After unsafe interpolation, the first single quote terminates the JSON argument, the semicolon begins another command, and the comment marker can suppress the remainder of the generated command. The same general issue applies to any user-controlled string inserted into this template without shell-safe encoding. The vulnerability arises from combining data serialization, shell parsing, and command execution in one interpolated string. JSON validation alone is insufficient because shell parsing occurs before `curl` processes the request. ### Attack Path 1. An attacker requests a numerology reading and supplies a crafted full name containing a single quote and shell metacharacters. 2. The agent or skill executor re ...[truncated 1391 chars]
Remediation
<![CDATA[ ## Remediation Suggestions 1. Do not interpolate user input into a shell command. 2. Use a structured HTTP client that serializes a native object directly to JSON. 3. If command-line `curl` is unavoidable, generate the JSON with a safe serializer such as `jq`: ```bash payload="$(jq -n \ --arg fullName "$full_name" \ --arg system "$system" \ --arg language "$language" \ --arg sessionId "$session_id" \ --arg timestamp "$timestamp" \ --argjson birthMonth "$birth_month" \ --argjson birthDay "$birth_day" \ --argjson birthYear "$birth_year" \ '{ fullName: $fullName, birthMonth: $birthMonth, birthDay: $birthDay, birthYear: $birthYear, system: $system, language: $language, sessionId: $sessionId, userId: 0, timestamp: $timestamp }' )" curl --fail-with-body --silent --show-error \ -X POST "https://portal.toolweb.in/apis/lifestyle/numerology" \ -H "Content-Type: application/json" \ -H "X-API-Key: $TOOLWEB_API_KEY" \ --data-binary "$payload" ``` 4. Prefer a process execution API that passes arguments as an array without invoking a shell. 5. Validate dates against real calendar rules and restrict enumerated fields to documented values. 6. Treat validation as defense in depth rather than as a replacement for correct serialization. 7. Do not log complete commands containing API keys or personal data. ]]>

other

Warning
Location
SKILL.md:71
Finding
Transmission of Personally Identifying Data Without an Explicit Consent Step<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md`, lines 71-98 **Vulnerability Type**: `other: Personal Data Disclosure` **Risk Level**: Medium ### Vulnerable Code ```markdown 1. **Gather inputs** from the user: **Required:** - `fullName` — Full name (as used commonly, e.g., "Krishnakumar Mahadevan") - `birthMonth` — Birth month (1-12) - `birthDay` — Birth day (1-31) - `birthYear` — Birth year (1900-2100) - `system` — Numerology system: "pythagorean" or "chaldean" **Optional:** - `language` — Output language: "english" (default), "tamil", "telugu", "kannada", "hindi" 2. **Call the API**: ```bash curl -s -X POST "https://portal.toolweb.in/apis/lifestyle/numerology" \ -H "Content-Type: application/json" \ -H "X-API-Key: $TOOLWEB_API_KEY" \ -d '{ "fullName": "<full_name>", "birthMonth": <month>, "birthDay": <day>, "birthYear": <year>, "system": "<pythagorean|chaldean>", "language": "<language>", "sessionId": "<unique-id>", "userId": 0, "timestamp": "<ISO-timestamp>" }' ``` ``` ### Technical Analysis The skill collects a full name and complete date of birth and transmits those values to `https://portal.toolweb.in`. A full name combined with a birth date is identifying personal data. The request also includes a session identifier and timestamp, which can facilitate correlation across requests or with server-side records. The documentation says that API requests are tracked for billing, but it does not require the agent to: - Tell the user that their personal data will leave the local environment. - Obtain explicit consent before transmission. - Explain retention, logging, deletion, or secondary-use policies. - Provide a privacy-policy reference. - Minimize or pseudonymize the submitted identity information. HTTPS protects data in transit from ordinary passive interception, but it does not prevent the receiving service from storing, analyzing, or correlating the data. ### At ...[truncated 1385 chars]
Remediation
<![CDATA[ ## Remediation Suggestions 1. Before making the request, clearly disclose: - The exact destination service. - The fields that will be transmitted. - That the request is externally processed and tracked. - Whether the operation consumes paid or limited quota. 2. Require explicit user consent before transmitting the first request. 3. Link to a privacy policy describing retention, logging, deletion, and secondary use. 4. Minimize submitted data. For example, avoid sending a real full name if the calculation can operate on a user-approved alias or locally derived representation. 5. Remove `sessionId`, `userId`, and `timestamp` unless each field is operationally necessary. 6. Generate nonpersistent, nonidentifying session identifiers where session state is required. 7. Do not submit information about third parties without confirmation that the user is authorized to provide it. 8. Provide a local calculation option so users can avoid disclosing personal data. 9. Avoid logging request bodies and redact names, birth dates, session identifiers, and API credentials from diagnostics. ]]>

SkillSpector

Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
Findings (4)

Missing User Warnings

Medium
Confidence
92% confidence
Finding
The README instructs users to configure an external service API key and demonstrates sending highly personal inputs such as full name and birth date, but it does not disclose that this data may be transmitted to a third-party service. Because numerology inherently uses personal data and the example includes identifying information, users may unknowingly expose sensitive personal data to an external API without informed consent.

Missing User Warnings

Medium
Confidence
94% confidence
Finding
The skill directs the agent to collect and transmit sensitive personal data including full name and full birth date to a third-party API, but it does not require any explicit user-facing privacy notice or consent before exfiltration. The risk is increased because the transmitted fields are sufficient for personal profiling and the skill strongly instructs that the API must always be called, discouraging safer local handling.

External Transmission

Medium
Category
Data Exfiltration
Content
2. **Call the API**:

```bash
curl -s -X POST "https://portal.toolweb.in/apis/lifestyle/numerology" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $TOOLWEB_API_KEY" \
  -d '{
Confidence
96% confidence
Finding
This curl command sends user-supplied PII and metadata to an external service at portal.toolweb.in, including full name, birth date, sessionId, userId, and timestamp. External transmission is not inherently malicious, but in this context it is risky because the skill mandates transmission of personal data to a third party without built-in consent, data minimization, or clear disclosure controls.

External Transmission

Medium
Category
Data Exfiltration
Content
2. User responds: "Pythagorean, in Hindi please"
3. Call API:
```bash
curl -s -X POST "https://portal.toolweb.in/apis/lifestyle/numerology" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $TOOLWEB_API_KEY" \
  -d '{
Confidence
95% confidence
Finding
The example interaction normalizes sending real user identity and birth-date data to an external API as part of standard operation. Because the example reinforces the 'always call the API' behavior, it increases the chance that agents will exfiltrate personal data by default without considering privacy, consent, or safer alternatives.

Static analysis

No suspicious patterns detected.