mythic-c2 0.2.2

//! High-level agent facade — build, send, and parse Mythic protocol messages.

use std::string::String;
use std::vec::Vec;
use uuid::Uuid;

#[cfg(feature = "rsa-staging")]
use crate::protocol::checkin::RespCheckin;
use crate::protocol::checkin::{self, DirectResult};
use crate::protocol::codec::{
    Aes256HmacCrypto, decode_message, decode_message_plain, encode_message, encode_message_plain,
};
use crate::protocol::{
    AgentExtras, AgentMessageExtras, ReqCheckin, ReqGetTasking, ReqPostResponse, RespGetTasking,
    RespPostResponse,
};
use crate::transport::C2Transport;
use crate::{MythicError, MythicResult};

/// Post-checkin phase — holds the callback UUID assigned by Mythic.
///
/// Encryption state is kept on the [`C2Transport`] via
/// [`get_aes_psk`](C2Transport::get_aes_psk) /
/// [`set_aes_psk`](C2Transport::set_aes_psk) so the same agent
/// can switch transports without duplicating key state.
///
/// # Examples
///
/// ```no_run
/// use mythic::{C2Transport, MythicAgent, MythicError};
/// use uuid::Uuid;
///
/// # struct HttpC2;
/// # impl C2Transport for HttpC2 {
/// #     fn checkin(&self, p: &str) -> Result<String, MythicError> { Ok(String::new()) }
/// #     fn get_tasking(&self, p: &str) -> Result<String, MythicError> { Ok(String::new()) }
/// #     fn post_response(&self, p: &str) -> Result<String, MythicError> { Ok(String::new()) }
/// # }
/// let mut c2 = HttpC2;
/// let payload_uuid = Uuid::parse_str("aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee").unwrap();
///
/// let agent = MythicAgent::easy_checkin(
///     payload_uuid,
///     &mut c2,
///     vec!["10.0.0.1".into()],
///     Some("linux".into()),
///     Some("root".into()),
///     Some("web01".into()),
///     Some(1337),
///     Some("x86_64".into()),
///     None, None, None, None, None, None,
/// )
/// .unwrap();
/// println!("callback UUID: {}", agent.callback_uuid());
/// ```
#[derive(Debug)]
pub struct MythicAgent {
    pub callback_uuid: Uuid,
}

impl MythicAgent {
    pub fn new(payload_uuid: Uuid) -> Self {
        Self {
            callback_uuid: payload_uuid,
        }
    }

    pub fn callback_uuid(&self) -> Uuid {
        self.callback_uuid
    }

    // ── Core message flow ──────────────────────────────────────

    /// One-shot checkin — create an agent and check it in, no `new()` needed.
    ///
    /// For full control use [`checkin`](Self::checkin) with a pre-built
    /// [`ReqCheckin`].
    #[allow(clippy::too_many_arguments)]
    pub fn easy_checkin<C: C2Transport>(
        payload_uuid: Uuid,
        c2: &mut C,
        ips: Vec<String>,
        os: Option<String>,
        user: Option<String>,
        host: Option<String>,
        pid: Option<u32>,
        architecture: Option<String>,
        domain: Option<String>,
        integrity_level: Option<u32>,
        external_ip: Option<String>,
        encryption_key: Option<String>,
        decryption_key: Option<String>,
        process_name: Option<String>,
    ) -> MythicResult<Self> {
        let req = ReqCheckin::new(
            payload_uuid,
            ips,
            os,
            user,
            host,
            pid,
            architecture,
            domain,
            integrity_level,
            external_ip,
            encryption_key,
            decryption_key,
            process_name,
        );
        Self::new(payload_uuid).checkin(req, c2)
    }

    /// Perform a direct checkin (plaintext or static-key PSK).
    ///
    /// The mode is determined automatically from the transport
    /// via [`C2Transport::get_aes_psk`].  `req.uuid` must be the payload
    /// UUID; it is used both in the JSON body and the wire framing.
    ///
    /// This method takes `&mut C` because RSA/translation staging may
    /// negotiate a new session key that must be stored back into the transport.
    pub fn checkin<C: C2Transport>(mut self, req: ReqCheckin, c2: &mut C) -> MythicResult<Self> {
        let payload_uuid = req.uuid;

        if c2.encrypted_exchange_check() {
            #[cfg(feature = "rsa-staging")]
            return self.rsa_checkin(req, c2);
            #[cfg(not(feature = "rsa-staging"))]
            return Err(MythicError::KeyExchangeFailed);
        }

        let needs_crypto = c2.get_aes_psk().is_some();
        let iv = if needs_crypto {
            c2.random_iv()?
        } else {
            [0u8; 16]
        };

        let DirectResult { callback_uuid, .. } =
            checkin::direct_checkin(c2, &req, payload_uuid, &iv)?;

        self.callback_uuid = callback_uuid;

        Ok(self)
    }

    /// Perform an RSA encrypted key exchange checkin.
    ///
    /// This is used when the transport reports
    /// [`C2Transport::encrypted_exchange_check`] as `true`. It executes the
    /// full `staging_rsa` → temp key → normal checkin flow.
    #[cfg(feature = "rsa-staging")]
    pub fn rsa_checkin<C: C2Transport>(
        mut self,
        req: ReqCheckin,
        c2: &mut C,
    ) -> MythicResult<Self> {
        use crate::protocol::checkin::{RsaStagingResult, rsa_staging_checkin};
        use crate::protocol::codec::encode_message;
        use crate::protocol::crypto::random_iv;

        let payload_uuid = req.uuid;
        let RsaStagingResult {
            temp_uuid, crypto, ..
        } = rsa_staging_checkin(&*c2, payload_uuid)?;

        // Persist the negotiated session key back into the transport so that
        // subsequent get_tasking/post_response calls use it.
        c2.set_aes_psk(&crypto.key_b64());

        let iv = random_iv()?;
        let packed = encode_message(&req, temp_uuid, &crypto, &iv)?;
        let response = c2.checkin(&packed)?;
        let (_, resp): (Uuid, RespCheckin) =
            crate::protocol::codec::decode_message(&response, Some(temp_uuid), &crypto)?;

        if resp.status != "success" {
            return Err(MythicError::protocol(format!(
                "checkin rejected after RSA staging: status={}",
                resp.status
            )));
        }

        self.callback_uuid = resp.id;
        Ok(self)
    }

    /// Poll for new tasks from the Mythic server (no extras).
    ///
    /// `tasking_size` of `-1` asks Mythic for all available tasks.
    pub fn get_tasking<C: C2Transport>(
        &self,
        tasking_size: i32,
        c2: &C,
    ) -> MythicResult<RespGetTasking> {
        self.get_tasking_with(tasking_size, c2, AgentMessageExtras::default())
    }

    /// Poll for new tasks, carrying delegates, SOCKS, RPFWD, interactive data,
    /// edges, alerts, and/or responses alongside the request.
    pub fn get_tasking_with<C: C2Transport>(
        &self,
        tasking_size: i32,
        c2: &C,
        extras: AgentMessageExtras,
    ) -> MythicResult<RespGetTasking> {
        let req = ReqGetTasking::with_extras(tasking_size, extras);

        if let Some(key_b64) = c2.get_aes_psk() {
            let crypto = Aes256HmacCrypto::from_base64_key(&key_b64)?;
            let iv = c2.random_iv()?;
            let packed = encode_message(&req, self.callback_uuid, &crypto, &iv)?;
            let response = c2.get_tasking(&packed)?;
            decode_message(&response, Some(self.callback_uuid), &crypto).map(|(_, r)| r)
        } else {
            let packed = encode_message_plain(&req, self.callback_uuid)?;
            let response = c2.get_tasking(&packed)?;
            decode_message_plain(&response, Some(self.callback_uuid)).map(|(_, r)| r)
        }
    }

    /// Send task responses back to the Mythic server (no extras).
    ///
    /// The `responses` vector contains the output of completed (or in-progress)
    /// tasks.  Use [`crate::protocol::TaskResponse`] builders like
    /// [`crate::protocol::TaskResponse::completed`] or construct custom
    /// responses with hooking-feature data.
    pub fn post_response<C: C2Transport>(
        &self,
        responses: Vec<crate::protocol::TaskResponse>,
        c2: &C,
    ) -> MythicResult<RespPostResponse> {
        self.post_response_with(responses, c2, AgentExtras::default())
    }

    /// Send task responses, carrying delegates, SOCKS, RPFWD, interactive data,
    /// edges, and/or alerts alongside the response.
    ///
    /// `shared` is the [`AgentExtras`] portion — it does **not** contain
    /// `responses` (those are the first argument).
    pub fn post_response_with<C: C2Transport>(
        &self,
        responses: Vec<crate::protocol::TaskResponse>,
        c2: &C,
        shared: AgentExtras,
    ) -> MythicResult<RespPostResponse> {
        let extras = AgentMessageExtras { responses, shared };
        let req = ReqPostResponse::from_extras(extras);

        if let Some(key_b64) = c2.get_aes_psk() {
            let crypto = Aes256HmacCrypto::from_base64_key(&key_b64)?;
            let iv = c2.random_iv()?;
            let packed = encode_message(&req, self.callback_uuid, &crypto, &iv)?;
            let response = c2.post_response(&packed)?;
            decode_message(&response, Some(self.callback_uuid), &crypto).map(|(_, r)| r)
        } else {
            let packed = encode_message_plain(&req, self.callback_uuid)?;
            let response = c2.post_response(&packed)?;
            decode_message_plain(&response, Some(self.callback_uuid)).map(|(_, r)| r)
        }
    }
}