AI_file

ai_file is a Mythic C2 profile that uses the publicly documented OpenAI Files API to exchange implant messages through jsonl files instead of a traditional HTTP/S listener. It relies on the Files API behavior defined by OpenAI in the public documentation: https://developers.openai.com/api/docs/guides/file-inputs?api-mode=responses.

The listener polls the /v1/files endpoint for .jsonl files with purpose=batch, decrypts each request envelope locally, forwards the raw Mythic message bytes to Mythic's /agent_message, encrypts Mythic's response, and uploads a response .jsonl file back to the Files API.

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Install

From the Mythic directory:

sudo ./mythic-cli install folder /path/to/openai_file
sudo ./mythic-cli c2 start openai_file

Listener Configuration

Edit C2_Profiles/openai_file/openai_file/c2_code/config.json before starting the profile:

{
  "instances": [
    {
      "name": "default",
      "api_key": "REPLACE_ME",
      "base_url": "https://api.openai.com/v1",
      "organization": "",
      "project": "",
      "purpose": "batch",
      "channel_id": "mythic",
      "request_prefix": "mythic_to_server",
      "response_prefix": "mythic_to_agent",
      "transport_key": "REPLACE_ME",
      "poll_interval_seconds": 5,
      "delete_processed_files": true,
      "debug": true,
      "max_file_bytes": 10485760,
      "mythic_host": "",
      "mythic_port": 0
    }
  ]
}

Required values are api_key, transport_key, and a matching channel_id between the listener and payload profile config. transport_key can be base64:<32 raw bytes> or a high-entropy passphrase; passphrases are SHA-256 derived before envelope encryption use.

Transport

Agents and the listener exchange files using OpenAI's Files API .jsonl files using purpose=batch.

Request filename:

<request_prefix>_<channel_id>_<request_id>.jsonl

Response filename:

<response_prefix>_<channel_id>_<request_id>.jsonl

Default request prefix is mythic_to_server; default response prefix is mythic_to_agent; default channel is mythic.

JSONL Envelope

Each file contains one or more JSON objects, one per line:

{"v":1,"profile":"openai_file","channel":"mythic","direction":"request","id":"req_001","alg":"aes-256-cbc-hmac-sha256+base64url","nonce":"...","ciphertext":"...","created_at":0}

ciphertext is AES-256-CBC output with a trailing HMAC-SHA256 tag over the raw Mythic message bytes. nonce is the CBC IV. nonce and ciphertext are unpadded base64url. AAD is:

v|profile|channel|direction|id|alg

For example:

1|openai_file|mythic|request|req_001|aes-256-cbc-hmac-sha256+base64url