T05 · Unauthorized Access and Privilege Escalation
- Location
SKILL.md:13- Finding
Unnecessary Arbitrary Command-Execution Capability
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 13–15; related declarations at lines 173, 190, and 225
Vulnerability Type: Excessive tool permissions and violation of least privilege
Risk Level: MediumVulnerable Code
yaml tools: - read - execThe Skill is also classified as command-enabled at line 190:
markdown - **Classification**: MD+EXEC()Its error-handling guidance at lines 173 and 225 recommends invoking the
pingcommand for network diagnostics.Technical Analysis
The declared purpose of this Skill is formatting plain text or Markdown. That operation requires access to document content but does not inherently require arbitrary operating-system command execution. Declaring the unrestricted
exectool therefore grants authority beyond the legitimate requirements of the task and violates the principle of least privilege.The documentation does not define an allowlist of permitted executables, constrain command arguments or destinations, require user confirmation, or isolate command execution in a sandbox. Although the audited package contains no malicious script or explicitly destructive command, an agent interpreting ambiguous, malformed, or attacker-controlled input could use the broadly available execution tool for operations unrelated to formatting.
The network-diagnostic guidance further establishes a path through which shell execution may occur despite network access not being necessary for local Markdown formatting. The issue is an excessive-capability exposure rather than evidence that the Skill currently contains an embedded malicious payload.
Attack Path
- The Skill is loaded by an agent and receives the declared
execcapability. - An attacker supplies crafted formatting content or instructions designed to be interpreted as an operational command or troubleshooting condition.
- Because the Skill contains generic instruction-parsing lan ...[truncated 1203 chars]
- The Skill is loaded by an agent and receives the declared
- Remediation
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Remediation Suggestions
- Remove
execfrom the declared tools because Markdown formatting does not require operating-system command execution. - Replace the
MD+EXEC()classification with a documentation-only or read/write capability classification appropriate to the actual formatting workflow. - Remove the instructions recommending
pingor other shell-based network diagnostics. Network connectivity is not required for local document formatting. - Restrict the Skill to narrowly scoped document-reading and document-writing tools, with access limited to user-selected files.
- Clearly state that document content is untrusted data and must never be interpreted as executable instructions.
- If command execution is genuinely required in a future version, use a fixed executable allowlist, validate every argument, prohibit shell interpolation, require explicit user approval, execute inside a sandbox, and apply restrictive filesystem and network policies.
- Add concrete input validation and output-handling rules instead of generic instruction-parsing directives that could blur the boundary between content and commands.
- Remove