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Security audit

Feishu Sheets

Security checks for vulnerabilities and agentic risk

Overview

The skill appears to be a Feishu Sheets integration, but its delete actions can remove spreadsheet content without a built-in confirmation step.

Install only if you trust it to modify Feishu spreadsheets. Use least-privileged Feishu app credentials, limit spreadsheet access, preview the target sheet or range first, and require explicit confirmation before delete_dimension or delete_sheet actions.

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • 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
  • Unauthorized Access and Privilege EscalationObtains permissions beyond the task's legitimate needs
Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Tool MisuseTool Parameter Abuse, Chaining Abuse, Unsafe Defaults
  • MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
Findings (9)

Credential Access

High
Category
Privilege Escalation
Confidence
70% confidence
Finding

Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.

Content

Scanner excerpt · references/api-reference.md (reported line 11)May include surrounding context.

Authentication

All API calls require a tenant access token in the Authorization header:

text
Authorization: Bearer {tenant_access_token}

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
80% confidence
Finding

Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).

Content

Scanner excerpt · references/api-reference.md (reported line 149)May include surrounding context.

md
### 7. Delete Rows/Columns

**Endpoint:** `DELETE /sheets/v2/spreadsheets/{spreadsheet_token}/dimension_range`

**Request Body:** Same as insert

Credential Access

High
Category
Privilege Escalation
Confidence
70% confidence
Finding

Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.

Content

Scanner excerpt · scripts/feishu_sheets.py (reported line 25)May include surrounding context.

python
self._token = None
        
    def _get_token(self) -> str:
        """Get tenant access token"""
        if self._token:
            return self._token

Undeclared Tool Scope

Medium
Category
MCP Least Privilege
Confidence
80% confidence
Finding

The skill exposes capabilities that can access external services and potentially environment-backed credentials, but it does not declare any explicit tool scope such as allowed-tools or permissions boundaries for the agent runtime. In a security-sensitive integration, this can lead to overly broad tool use, unclear privilege boundaries, and accidental misuse of networked functionality beyond what the skill documentation narrowly describes.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The skill documents destructive actions such as delete_dimension and delete_sheet without requiring confirmation, warning about irreversible effects, or recommending preview/safeguard flows. In the context of a spreadsheet-management skill, this materially increases the chance of accidental or socially engineered data loss because the skill is specifically designed to modify and delete user content.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

This markdown file documents deletion operations for rows/columns and worksheets, which can affect user data and system integrity. The description provides endpoints and request bodies but does not include any warning, caution, or note that these operations may permanently remove spreadsheet content.

Content

No source excerpt is available for this finding.

External Transmission

Medium
Category
Data Exfiltration
Confidence
80% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · scripts/feishu_sheets.py (reported line 29)May include surrounding context.

python
if self._token:
            return self._token
            
        resp = requests.post(AUTH_API, json={
            "app_id": self.app_id,
            "app_secret": self.app_secret
        })

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

The code performs a destructive delete operation against spreadsheet dimensions via the Feishu API, but provides no confirmation prompt or user-facing warning before removing rows or columns. Although the method has an internal docstring, the CLI path exposes this irreversible action without any disclosure to the user at invocation time.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
93% confidence
Finding

This method deletes an entire worksheet through the remote API, which is a destructive operation affecting user data. The implementation does not include a confirmation prompt, warning message, or other user disclosure beyond an internal docstring.

Content

No source excerpt is available for this finding.