Back to skill

Security audit

Smux

Security checks for vulnerabilities and agentic risk

Overview

The skill is a coherent tmux collaboration helper, but its mandatory reply routing can send final results to another pane based only on mutable tmux state.

Install only if you intentionally want agents to communicate through a shared tmux session. Before using it with sensitive work, make sure tmux panes are trusted and treat `pending`/`reply` routing as cross-pane disclosure. Confirm session names before `kill-session`, and be deliberate before appending auto-label configuration to `~/.tmux.conf`.

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
Findings (1)

T01 · Skill Instruction Hijacking

Error
Location
SKILL.md:45
Finding

Mandatory Cross-Pane Reply Routing Based on Mutable tmux State

Content
View full analysis
'`. 3. If `pending` has no pending items, treat the request as ordinary user input and do not call `reply`. 4. When assigning tasks to other agents, use an explicit mode by default: - Use `--expect-reply` when a result is required. - Use `--no-reply` for notifications only. 5. Do not return ineffective content such as “received,” “processing,” or “thanks”; even when nothing is found, explicitly reply with “no findings.” 6. If `tmux-bridge reply` reports `no pending reply target for this pane`, there is no automatic reply target; manually use `tmux-bridge send --no-reply ''`. ``` The displayed excerpt is an English translation of the instructions at the specified source location. ### Technical Analysis The skill requires the agent to run `tmux-bridge pending` before every final response and treats its mutable output as the sole authority for determining request provenance. If the command reports a `waiting` or `overdue` request, the skill requires the agent to transmit its final conclusion through `tmux-bridge reply` rather than returning it only through the original interaction channel. This behavior delegates response-routing decisions to shared tmux session state. Any process or participant able to create an expected-reply request for the current pane can potentially influence where the agent sends its result. The instructions do not require authentication of the orig ...[truncated 2072 chars]
Remediation
View remediation
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)

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The skill body and operational guidance are written in Chinese, while the manifest description is in English, and there is no statement that the skill is intentionally Chinese-only or that users may choose a preferred language. This creates a language-policy concern because the skill effectively imposes a locale without opt-in or documented justification.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

The operational instructions in this file are written in Chinese, and there is no indication that language selection is optional or that the skill is intended only for a Chinese-language context. This can violate a language/locale policy when users are not given an opt-in or alternative language.

Content

No source excerpt is available for this finding.

Missing User Warnings

Low
Category
Not specified by scanner
Confidence
85% confidence
Finding

This markdown file documents kill-session as a quick way to close an entire tmux session, which can terminate running pane processes and discard active work. The description provides no warning about the impact or recommendation to verify the target session before use.

Content

No source excerpt is available for this finding.

Missing User Warnings

Low
Category
Not specified by scanner
Confidence
87% confidence
Finding

This markdown file describes kill-session / -k commands that terminate a tmux session, which can disrupt active work and potentially discard unsaved terminal state. The document presents the commands as routine usage examples but does not include any warning or caution about the destructive impact.

Content

No source excerpt is available for this finding.