GHSA-3r68-x3xc-rxpg wireshark-mcp vulnerable to arbitrary file write via export_objects when WIRESHARK_MCP_ALLOWED_DIRS is not configured

• PyPI wireshark-mcp: <= 1.1.5 (no fix yet)

Description Impact `wireshark-mcp` exposes a `wireshark_export_objects` MCP tool that accepts an attacker-controlled `dest_dir` parameter and passes it to tshark's `--export-objects` flag with no mandatory path restriction. The path sandbox (`_allowed_dirs`) is `None` by default and only activates when the environment variable `WIRESHARK_MCP_ALLOWED_DIRS` is explicitly set. In a default installation, any directory on the filesystem can be used as the export destination. Affected code (`src/wireshark_mcp/tshark/client.py:531-543`): ```python output_validation = self._validate_output_path(dest_dir) _validate_output_path only enforces the sandbox when _allowed_dirs is set. Default: _allowed_dirs = None → no restriction. os.makedirs(dest_dir, exist_ok=True) # creates arbitrary directories cmd = [..., "--export-objects", f"{protocol},{dest_dir}"] ``` Attack Scenario An attacker embeds a crafted HTTP response in a pcap file (e.g. `Content-Disposition: filename=authorized_keys`). Via prompt injection in the pcap payload, an AI model using this MCP server is manipulated into calling `wireshark_export_objects` with: ```bash dest_dir=/home/user/.ssh/ ``` `tshark` then extracts and writes the HTTP object to that path, granting the attacker SSH access. The same technique can target: • `/etc/cron.d/` • Writable web roots • Other sensitive filesystem locations Additional Affected Operations The same missing sandbox affects: • `merge_pcap_files` • `editcap_trim` • `editcap_split` • `editcap_time_shift` • `editcap_deduplicate` • `text2pcap_import` Proof of Concept Confirmed on wireshark-mcp v1.1.5 with tshark 4.6.4. A crafted pcap’s HTTP object was successfully written to an arbitrary filesystem path when: ```python _allowed_dirs = None ``` --- Patches Not yet patched. A fix should make the path sandbox mandatory for all file-write operations rather than optional: ```python Reject all write operations when no sandbox is configured if not self._allowed_dirs: return json.dumps({ "success": False, "error": { "type": "SecurityError", "message": "Set WIRESHARK_MCP_ALLOWED_DIRS before using file-write operations" } }) ``` --- Workarounds Set `WIRESHARK_MCP_ALLOWED_DIRS` to a restricted safe directory before starting the server: ```bash export WIRESHARK_MCP_ALLOWED_DIRS=/tmp/wireshark_mcp_safe ``` This activates the existing sandbox and blocks writes outside the allowed path. --- Resources • Vulnerable code: • `src/wireshark_mcp/tshark/client.py` lines 521–543 • `src/wireshark_mcp/tshark/client.py` lines 685–839 • CWE-22: Improper Limitation of a Pathname to a Restricted Directory • CWE-73: External Control of File Name or Path