refactor(werkbank): extract soft-PLC provisioning + ICS probe into werkbank-exec (WB-04a) (#208)

werkbank-exec/src/ics/ethernetip.rs

@@ -0,0 +1,95 @@
+//! Minimal EtherNet/IP (CIP) reachability probe.
+//!
+//! Sends an EtherNet/IP encapsulation **ListIdentity** command (0x0063) over TCP
+//! 44818 and checks for a valid encapsulation reply — confirming a CIP device
+//! without opening a session or writing anything.
+
+use std::time::Duration;
+
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpStream;
+use tokio::time::timeout;
+
+/// Outcome of an EtherNet/IP handshake probe.
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct EnipProbe {
+    /// A TCP connection to the port was established.
+    pub reachable: bool,
+    /// The endpoint returned a valid EtherNet/IP encapsulation reply.
+    pub is_enip: bool,
+}
+
+/// Probe an EtherNet/IP endpoint with a ListIdentity request. Read-only.
+pub async fn probe(host: &str, port: u16, budget: Duration) -> EnipProbe {
+    let mut out = EnipProbe::default();
+    let Ok(Ok(mut stream)) = timeout(budget, TcpStream::connect((host, port))).await else {
+        return out;
+    };
+    out.reachable = true;
+
+    // Encapsulation header (24 bytes): command(2) length(2) session(4) status(4)
+    // context(8) options(4). ListIdentity = command 0x0063, everything else zero.
+    let mut req = vec![0u8; 24];
+    req[0..2].copy_from_slice(&0x0063u16.to_le_bytes());
+    if timeout(budget, stream.write_all(&req))
+        .await
+        .ok()
+        .and_then(Result::ok)
+        .is_none()
+    {
+        return out;
+    }
+
+    let mut hdr = [0u8; 24];
+    if timeout(budget, stream.read_exact(&mut hdr))
+        .await
+        .ok()
+        .and_then(Result::ok)
+        .is_none()
+    {
+        return out;
+    }
+    let command = u16::from_le_bytes([hdr[0], hdr[1]]);
+    let status = u32::from_le_bytes([hdr[8], hdr[9], hdr[10], hdr[11]]);
+    // Echoed command + success status = a valid EtherNet/IP encapsulation reply.
+    if command == 0x0063 && status == 0 {
+        out.is_enip = true;
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::net::TcpListener;
+
+    async fn mock_server() -> std::net::SocketAddr {
+        let listener = TcpListener::bind("127.0.0.1:0").await.expect("bind");
+        let addr = listener.local_addr().expect("addr");
+        tokio::spawn(async move {
+            let (mut sock, _) = listener.accept().await.expect("accept");
+            let mut req = [0u8; 24];
+            if sock.read_exact(&mut req).await.is_err() {
+                return;
+            }
+            // Reply: echo command 0x0063, status 0, no data.
+            let mut hdr = vec![0u8; 24];
+            hdr[0..2].copy_from_slice(&0x0063u16.to_le_bytes());
+            let _ = sock.write_all(&hdr).await;
+        });
+        addr
+    }
+
+    #[tokio::test]
+    async fn probe_detects_an_ethernetip_device() {
+        let addr = mock_server().await;
+        let p = probe(&addr.ip().to_string(), addr.port(), Duration::from_secs(2)).await;
+        assert!(p.reachable && p.is_enip);
+    }
+
+    #[tokio::test]
+    async fn probe_reports_unreachable_for_a_closed_port() {
+        let p = probe("127.0.0.1", 1, Duration::from_millis(500)).await;
+        assert!(!p.reachable && !p.is_enip);
+    }
+}

werkbank-exec/src/ics/mod.rs

@@ -0,0 +1,306 @@
+//! Dynamic ICS (industrial control system) probing for PLC/SPS targets.
+//!
+//! Where the control-logic scanner is static (over ST / PLCopen XML), this probes
+//! the *running* device over industrial protocols and reports exposed /
+//! unauthenticated control interfaces. It is read-only: it never writes to a live
+//! process. Modbus/TCP and OPC UA are implemented; EtherNet-IP is a follow-on.
+
+pub mod ethernetip;
+pub mod modbus;
+pub mod opcua;
+pub mod portscan;
+
+use std::time::Duration;
+
+use compliance_core::models::{Finding, ScanType, Severity};
+
+use crate::fingerprint as dedup;
+
+/// Well-known deep-probe ports (each independent of any WebVisu HTTP port).
+const MODBUS_PORT: u16 = 502;
+const OPCUA_PORT: u16 = 4840;
+const ENIP_PORT: u16 = 44818;
+
+/// Probe a PLC/SPS device's industrial-protocol surface and return findings.
+/// Read-only. Deep-probes Modbus/TCP, OPC UA and EtherNet/IP, plus a service
+/// discovery scan of the remaining OT / insecure-management ports. `endpoint` is
+/// the target's live-URL / host reference.
+pub async fn probe_target(endpoint: &str, repo_id: &str, budget: Duration) -> Vec<Finding> {
+    let (host, modbus_port) = parse_endpoint(endpoint);
+    let mut findings = modbus_findings(&host, modbus_port, repo_id, budget).await;
+    findings.extend(opcua_findings(&host, OPCUA_PORT, repo_id, budget).await);
+    findings.extend(enip_findings(&host, ENIP_PORT, repo_id, budget).await);
+    findings.extend(portscan_findings(&host, repo_id, budget).await);
+    findings
+}
+
+/// Findings from probing the Modbus/TCP surface.
+async fn modbus_findings(host: &str, port: u16, repo_id: &str, budget: Duration) -> Vec<Finding> {
+    let probe = modbus::probe(host, port, budget).await;
+    let mut findings = Vec::new();
+    if !probe.speaks_modbus {
+        // Not reachable, or the port does not speak Modbus — nothing to report.
+        return findings;
+    }
+    let target = format!("{host}:{port}");
+
+    // Reachable Modbus/TCP = unauthenticated, cleartext control access by design.
+    let fp = dedup::compute_fingerprint(&[repo_id, "ics-modbus-exposed", &target]);
+    let mut f = Finding::new(
+        repo_id.to_string(),
+        fp,
+        "ics-probe".to_string(),
+        ScanType::IcsProbe,
+        "Modbus/TCP control interface exposed without authentication".to_string(),
+        format!(
+            "The device at {target} answers Modbus/TCP requests. Modbus/TCP has no \
+             authentication or encryption in the protocol, so any host that can reach this \
+             port can read and write process variables (coils/registers) and disrupt the \
+             controlled process."
+        ),
+        Severity::Critical,
+    );
+    f.rule_id = Some("ics-modbus-exposed".to_string());
+    f.cwe = Some("CWE-306".to_string());
+    f.remediation = Some(
+        "Restrict the Modbus/TCP port to a trusted control network (segmentation / \
+         firewall / VPN), never expose it to IT or the internet, and prefer an authenticated \
+         transport (e.g. Modbus/TLS) or a secure protocol gateway where available."
+            .to_string(),
+    );
+    findings.push(f);
+
+    if let Some(dev) = &probe.device {
+        let details = [
+            dev.vendor.as_deref(),
+            dev.product.as_deref(),
+            dev.revision.as_deref(),
+        ]
+        .into_iter()
+        .flatten()
+        .collect::<Vec<_>>()
+        .join(" / ");
+        let fp = dedup::compute_fingerprint(&[repo_id, "ics-device-disclosure", &target]);
+        let mut f = Finding::new(
+            repo_id.to_string(),
+            fp,
+            "ics-probe".to_string(),
+            ScanType::IcsProbe,
+            "PLC device identity disclosed over Modbus".to_string(),
+            format!(
+                "The device at {target} discloses its identity via Modbus Read Device \
+                 Identification: {details}. This aids fingerprinting and targeting of \
+                 known-vulnerable firmware/runtime versions."
+            ),
+            Severity::Low,
+        );
+        f.rule_id = Some("ics-device-disclosure".to_string());
+        f.cwe = Some("CWE-200".to_string());
+        f.remediation = Some(
+            "Limit network reach to the device; Modbus device identification cannot be \
+             disabled, so exposure is bounded by network segmentation."
+                .to_string(),
+        );
+        findings.push(f);
+    }
+
+    // Exposed process points: coils / holding registers that a read enumerated
+    // and that, over unauthenticated Modbus/TCP, are also writable. This is the
+    // concrete attack surface behind the exposure — the live variables an
+    // attacker can overwrite. (Read-only to detect: we never write.)
+    let coils = probe.coils_readable.unwrap_or(0);
+    let registers = probe.holding_registers_readable.unwrap_or(0);
+    if coils > 0 || registers > 0 {
+        let fp = dedup::compute_fingerprint(&[repo_id, "ics-modbus-exposed-points", &target]);
+        let mut f = Finding::new(
+            repo_id.to_string(),
+            fp,
+            "ics-probe".to_string(),
+            ScanType::IcsProbe,
+            "Writable process points exposed over unauthenticated Modbus/TCP".to_string(),
+            format!(
+                "Reading the device at {target} enumerated {coils} coil(s) and {registers} \
+                 holding register(s). Coils and holding registers are read/write process points \
+                 in Modbus, so any host that can reach this port can not only read but overwrite \
+                 live process state (force coils, change setpoints) without authentication."
+            ),
+            Severity::High,
+        );
+        f.rule_id = Some("ics-modbus-exposed-points".to_string());
+        f.cwe = Some("CWE-306".to_string());
+        f.remediation = Some(
+            "Segment the Modbus/TCP port to a trusted control network; where the device \
+             supports it use Modbus/TLS or an authenticating protocol gateway; restrict which \
+             function codes and register ranges are reachable from outside the control zone."
+                .to_string(),
+        );
+        findings.push(f);
+    }
+    findings
+}
+
+/// Findings from probing the OPC UA surface (default port 4840). A reachability
+/// probe only: it flags an exposed OPC UA server for review of its security
+/// policy / authentication (deep SecurityPolicy analysis is a follow-on).
+async fn opcua_findings(host: &str, port: u16, repo_id: &str, budget: Duration) -> Vec<Finding> {
+    let probe = opcua::probe(host, port, budget).await;
+    let mut findings = Vec::new();
+    if !probe.is_opcua {
+        return findings;
+    }
+    let target = format!("{host}:{port}");
+    let fp = dedup::compute_fingerprint(&[repo_id, "ics-opcua-exposed", &target]);
+    let mut f = Finding::new(
+        repo_id.to_string(),
+        fp,
+        "ics-probe".to_string(),
+        ScanType::IcsProbe,
+        "OPC UA server exposed on the network".to_string(),
+        format!(
+            "An OPC UA server answers at {target}. Verify it enforces message security \
+             (a SecurityPolicy other than None) and rejects anonymous sessions — the common \
+             default of SecurityPolicy None + an Anonymous user token allows unauthenticated, \
+             unencrypted read/write of the server's address space."
+        ),
+        Severity::Medium,
+    );
+    f.rule_id = Some("ics-opcua-exposed".to_string());
+    f.cwe = Some("CWE-319".to_string());
+    f.remediation = Some(
+        "Restrict OPC UA (4840) to a trusted network; require a signed & encrypted \
+         SecurityPolicy (Basic256Sha256 or better) with certificate / username \
+         authentication, and disable the Anonymous user token."
+            .to_string(),
+    );
+    findings.push(f);
+    findings
+}
+
+/// Findings from probing the EtherNet/IP (CIP) surface (default port 44818).
+async fn enip_findings(host: &str, port: u16, repo_id: &str, budget: Duration) -> Vec<Finding> {
+    let probe = ethernetip::probe(host, port, budget).await;
+    if !probe.is_enip {
+        return Vec::new();
+    }
+    let target = format!("{host}:{port}");
+    let fp = dedup::compute_fingerprint(&[repo_id, "ics-ethernetip-exposed", &target]);
+    let mut f = Finding::new(
+        repo_id.to_string(),
+        fp,
+        "ics-probe".to_string(),
+        ScanType::IcsProbe,
+        "EtherNet/IP (CIP) interface exposed on the network".to_string(),
+        format!(
+            "The device at {target} answers EtherNet/IP (CIP) requests. EtherNet/IP has no \
+             authentication in the base protocol, so a host that can reach it can enumerate \
+             and interact with the device's control objects."
+        ),
+        Severity::High,
+    );
+    f.rule_id = Some("ics-ethernetip-exposed".to_string());
+    f.cwe = Some("CWE-306".to_string());
+    f.remediation = Some(
+        "Restrict EtherNet/IP (44818/2222) to a trusted control network; use CIP Security \
+         (encryption + authentication) on devices that support it."
+            .to_string(),
+    );
+    vec![f]
+}
+
+/// Findings from the service-discovery port scan of the remaining OT /
+/// insecure-management surface.
+async fn portscan_findings(host: &str, repo_id: &str, budget: Duration) -> Vec<Finding> {
+    let open = portscan::scan(host, portscan::KNOWN_PORTS, budget).await;
+    open.into_iter()
+        .map(|kp| {
+            let target = format!("{host}:{}", kp.port);
+            let (title, severity, cwe, description) = match kp.kind {
+                portscan::PortKind::Ics => (
+                    format!("ICS service exposed: {}", kp.service),
+                    Severity::High,
+                    "CWE-306",
+                    format!(
+                        "{target} exposes {} ({}). Industrial protocols are typically \
+                         unauthenticated, so network reach implies control access.",
+                        kp.service, kp.note
+                    ),
+                ),
+                portscan::PortKind::InsecureMgmt => (
+                    format!("Cleartext service exposed: {}", kp.service),
+                    Severity::Medium,
+                    "CWE-319",
+                    format!(
+                        "{target} exposes {} ({}), which transmits credentials and data in \
+                         cleartext.",
+                        kp.service, kp.note
+                    ),
+                ),
+            };
+            let fp = dedup::compute_fingerprint(&[repo_id, "ics-service-exposed", &target]);
+            let mut f = Finding::new(
+                repo_id.to_string(),
+                fp,
+                "ics-probe".to_string(),
+                ScanType::IcsProbe,
+                title,
+                description,
+                severity,
+            );
+            f.rule_id = Some("ics-service-exposed".to_string());
+            f.cwe = Some(cwe.to_string());
+            f.remediation = Some(
+                "Restrict the service to a trusted network segment; disable it if unused; \
+                 replace cleartext protocols (Telnet/FTP) with SSH/SFTP."
+                    .to_string(),
+            );
+            f
+        })
+        .collect()
+}
+
+/// Extract `(host, port)` from a target reference. Modbus lives on its own port
+/// (502 by default), independent of any HTTP/WebVisu URL, so unless the reference
+/// explicitly carries `modbus://host:port` or a bare `host:port`, we probe 502.
+fn parse_endpoint(endpoint: &str) -> (String, u16) {
+    let s = endpoint.trim();
+    let (scheme, rest) = match s.split_once("://") {
+        Some((sch, r)) => (Some(sch.to_ascii_lowercase()), r),
+        None => (None, s),
+    };
+    let hostport = rest.split(['/', '?']).next().unwrap_or(rest);
+    let (host, port) = match hostport.rsplit_once(':') {
+        Some((h, p)) => (h.to_string(), p.parse::<u16>().ok()),
+        None => (hostport.to_string(), None),
+    };
+    let port = match (scheme.as_deref(), port) {
+        // Explicit Modbus port, or a bare host:port the user chose.
+        (Some("modbus"), Some(p)) | (None, Some(p)) => p,
+        // An http(s)/WebVisu URL (or no port): Modbus is on its own port.
+        _ => MODBUS_PORT,
+    };
+    (host, port)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::parse_endpoint;
+
+    #[test]
+    fn endpoint_parsing_picks_the_modbus_port() {
+        assert_eq!(parse_endpoint("10.0.0.5"), ("10.0.0.5".into(), 502));
+        assert_eq!(parse_endpoint("10.0.0.5:1502"), ("10.0.0.5".into(), 1502));
+        assert_eq!(
+            parse_endpoint("modbus://plc.local:5020"),
+            ("plc.local".into(), 5020)
+        );
+        // A WebVisu URL: the http port is ignored; Modbus is on 502.
+        assert_eq!(
+            parse_endpoint("http://plc.local:8080/webvisu"),
+            ("plc.local".into(), 502)
+        );
+        assert_eq!(
+            parse_endpoint("https://plc.local/"),
+            ("plc.local".into(), 502)
+        );
+    }
+}

werkbank-exec/src/ics/modbus.rs

@@ -0,0 +1,262 @@
+//! Minimal Modbus/TCP client for dynamic ICS probing.
+//!
+//! Modbus/TCP (port 502) has no authentication or encryption in the protocol, so
+//! an endpoint that answers requests is, by design, open to any host that can
+//! reach it. The probe only *reads* — a Read Holding Registers request and a Read
+//! Device Identification request — and never writes to the live process.
+
+use std::time::Duration;
+
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpStream;
+use tokio::time::timeout;
+
+/// Outcome of probing a Modbus/TCP endpoint.
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct ModbusProbe {
+    /// A TCP connection to the port was established.
+    pub reachable: bool,
+    /// The endpoint answered a Modbus request (a normal reply or a Modbus
+    /// exception) — i.e. it speaks Modbus, unauthenticated.
+    pub speaks_modbus: bool,
+    /// Device identity, if disclosed via Read Device Identification (FC 43 / 14).
+    pub device: Option<DeviceId>,
+    /// Coils returned by a Read Coils of the first block, if that address range
+    /// exists. Coils are read/write process bits, so an exposed block is an
+    /// unauthenticated write surface on the live process.
+    pub coils_readable: Option<u16>,
+    /// Holding registers returned by a Read Holding Registers of the first block,
+    /// if that range exists. Holding registers are read/write process words.
+    pub holding_registers_readable: Option<u16>,
+}
+
+/// Vendor / product / revision from Read Device Identification.
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct DeviceId {
+    pub vendor: Option<String>,
+    pub product: Option<String>,
+    pub revision: Option<String>,
+}
+
+/// How many coils / holding registers to request when enumerating the exposed
+/// process surface. Read-only: a normal reply means the block exists and is,
+/// over unauthenticated Modbus/TCP, also writable.
+const ENUM_QTY: u16 = 16;
+
+/// Probe a Modbus/TCP endpoint. Read-only: issues Read Holding Registers, Read
+/// Coils, and Read Device Identification requests; never writes to the device.
+pub async fn probe(host: &str, port: u16, budget: Duration) -> ModbusProbe {
+    let mut out = ModbusProbe::default();
+    let Ok(Ok(mut stream)) = timeout(budget, TcpStream::connect((host, port))).await else {
+        return out; // unreachable
+    };
+    out.reachable = true;
+
+    // Read Holding Registers (FC 0x03), unit 1, addr 0 — a benign read that also
+    // enumerates the exposed register block.
+    let rhr = [0x03u8, 0x00, 0x00, (ENUM_QTY >> 8) as u8, ENUM_QTY as u8];
+    if let Some(resp) = txn(&mut stream, 1, &rhr, budget).await {
+        // A normal reply (0x03) or an exception (0x83) both prove it speaks Modbus.
+        if matches!(resp.first(), Some(0x03) | Some(0x83)) {
+            out.speaks_modbus = true;
+        }
+        if resp.first() == Some(&0x03) {
+            out.holding_registers_readable = Some(register_count_from_reply(&resp));
+        }
+    }
+
+    // Read Coils (FC 0x01), addr 0 — enumerates the exposed coil (bit) block.
+    let rc = [0x01u8, 0x00, 0x00, (ENUM_QTY >> 8) as u8, ENUM_QTY as u8];
+    if let Some(resp) = txn(&mut stream, 1, &rc, budget).await {
+        if matches!(resp.first(), Some(0x01) | Some(0x81)) {
+            out.speaks_modbus = true;
+        }
+        if resp.first() == Some(&0x01) {
+            out.coils_readable = Some(coil_count_from_reply(&resp));
+        }
+    }
+
+    // Read Device Identification (FC 0x2B / MEI 0x0E), basic (0x01), object 0.
+    let rdi = [0x2Bu8, 0x0E, 0x01, 0x00];
+    if let Some(resp) = txn(&mut stream, 1, &rdi, budget).await {
+        if resp.first() == Some(&0x2B) {
+            out.speaks_modbus = true;
+            out.device = parse_device_id(&resp);
+        }
+    }
+    out
+}
+
+/// Coils reported by a Read Coils reply `[0x01, byte_count, data…]` (8 per byte).
+fn coil_count_from_reply(pdu: &[u8]) -> u16 {
+    pdu.get(1).map(|&b| u16::from(b) * 8).unwrap_or(0)
+}
+
+/// Registers reported by a Read Holding Registers reply `[0x03, byte_count,
+/// data…]` (2 bytes per register).
+fn register_count_from_reply(pdu: &[u8]) -> u16 {
+    pdu.get(1).map(|&b| u16::from(b) / 2).unwrap_or(0)
+}
+
+/// Send one Modbus PDU and return the response PDU (function code + data), or
+/// `None` on timeout / malformed reply.
+async fn txn(stream: &mut TcpStream, unit: u8, pdu: &[u8], budget: Duration) -> Option<Vec<u8>> {
+    // MBAP header: transaction id (2) + protocol id (2) = 0 + length (2) + unit (1),
+    // then the PDU. `length` counts the unit byte plus the PDU.
+    let len = (pdu.len() + 1) as u16;
+    let mut frame = Vec::with_capacity(7 + pdu.len());
+    frame.extend_from_slice(&[0x00, 0x01]); // transaction id
+    frame.extend_from_slice(&[0x00, 0x00]); // protocol id
+    frame.extend_from_slice(&len.to_be_bytes());
+    frame.push(unit);
+    frame.extend_from_slice(pdu);
+    timeout(budget, stream.write_all(&frame)).await.ok()?.ok()?;
+
+    let mut hdr = [0u8; 7];
+    timeout(budget, stream.read_exact(&mut hdr))
+        .await
+        .ok()?
+        .ok()?;
+    // Reject non-Modbus replies (protocol id must be 0).
+    if hdr[2] != 0 || hdr[3] != 0 {
+        return None;
+    }
+    let plen = u16::from_be_bytes([hdr[4], hdr[5]]) as usize;
+    if !(2..=260).contains(&plen) {
+        return None;
+    }
+    let mut body = vec![0u8; plen - 1]; // minus the unit id already in hdr[6]
+    timeout(budget, stream.read_exact(&mut body))
+        .await
+        .ok()?
+        .ok()?;
+    Some(body)
+}
+
+/// Parse vendor / product / revision from a Read Device Identification PDU:
+/// `[0x2B, 0x0E, readDevIdCode, conformity, moreFollows, nextObjId, numObjects,
+/// (objId, len, bytes…)…]`.
+fn parse_device_id(pdu: &[u8]) -> Option<DeviceId> {
+    if pdu.len() < 7 {
+        return None;
+    }
+    let num = pdu[6] as usize;
+    let mut i = 7;
+    let mut dev = DeviceId::default();
+    for _ in 0..num {
+        if i + 2 > pdu.len() {
+            break;
+        }
+        let id = pdu[i];
+        let l = pdu[i + 1] as usize;
+        i += 2;
+        if i + l > pdu.len() {
+            break;
+        }
+        let val = String::from_utf8_lossy(&pdu[i..i + l]).trim().to_string();
+        i += l;
+        match id {
+            0x00 => dev.vendor = Some(val),
+            0x01 => dev.product = Some(val),
+            0x02 => dev.revision = Some(val),
+            _ => {}
+        }
+    }
+    if dev == DeviceId::default() {
+        None
+    } else {
+        Some(dev)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::net::TcpListener;
+
+    /// A one-shot mock Modbus/TCP server that answers a Read Holding Registers
+    /// request and a Read Device Identification request on one connection.
+    async fn mock_server(with_device: bool) -> std::net::SocketAddr {
+        let listener = TcpListener::bind("127.0.0.1:0").await.expect("bind");
+        let addr = listener.local_addr().expect("addr");
+        tokio::spawn(async move {
+            let (mut sock, _) = listener.accept().await.expect("accept");
+            loop {
+                let mut hdr = [0u8; 7];
+                if sock.read_exact(&mut hdr).await.is_err() {
+                    break;
+                }
+                let plen = u16::from_be_bytes([hdr[4], hdr[5]]) as usize;
+                let mut pdu = vec![0u8; plen - 1];
+                if sock.read_exact(&mut pdu).await.is_err() {
+                    break;
+                }
+                let reply_pdu: Vec<u8> = match pdu.first() {
+                    Some(0x03) => vec![0x03, 0x02, 0x00, 0x00], // 1 register (byte_count 2)
+                    Some(0x01) => vec![0x01, 0x02, 0xFF, 0xFF], // 16 coils (byte_count 2)
+                    Some(0x2B) if with_device => vec![
+                        0x2B, 0x0E, 0x01, 0x81, 0x00, 0x00, 0x02, // 2 objects
+                        0x00, 0x04, b'A', b'C', b'M', b'E', // vendor
+                        0x01, 0x03, b'P', b'L', b'C', // product
+                    ],
+                    _ => vec![pdu[0] | 0x80, 0x01], // exception
+                };
+                let len = (reply_pdu.len() + 1) as u16;
+                let mut frame = vec![hdr[0], hdr[1], 0x00, 0x00];
+                frame.extend_from_slice(&len.to_be_bytes());
+                frame.push(hdr[6]);
+                frame.extend_from_slice(&reply_pdu);
+                if sock.write_all(&frame).await.is_err() {
+                    break;
+                }
+            }
+        });
+        addr
+    }
+
+    #[tokio::test]
+    async fn probe_detects_a_modbus_endpoint_and_reads_device_id() {
+        let addr = mock_server(true).await;
+        let p = probe(&addr.ip().to_string(), addr.port(), Duration::from_secs(2)).await;
+        assert!(p.reachable && p.speaks_modbus);
+        let dev = p.device.expect("device id");
+        assert_eq!(dev.vendor.as_deref(), Some("ACME"));
+        assert_eq!(dev.product.as_deref(), Some("PLC"));
+    }
+
+    #[tokio::test]
+    async fn probe_enumerates_exposed_process_points() {
+        let addr = mock_server(false).await;
+        let p = probe(&addr.ip().to_string(), addr.port(), Duration::from_secs(2)).await;
+        assert!(p.speaks_modbus);
+        // The mock returns a 2-byte holding-register block (1 register) and a
+        // 2-byte coil block (16 coils).
+        assert_eq!(p.holding_registers_readable, Some(1));
+        assert_eq!(p.coils_readable, Some(16));
+    }
+
+    #[test]
+    fn reply_counts_decode_byte_counts() {
+        assert_eq!(register_count_from_reply(&[0x03, 0x08]), 4); // 8 bytes → 4 regs
+        assert_eq!(coil_count_from_reply(&[0x01, 0x03]), 24); // 3 bytes → 24 coils
+        assert_eq!(register_count_from_reply(&[0x03]), 0); // malformed → 0
+    }
+
+    #[tokio::test]
+    async fn probe_reports_unreachable_for_a_closed_port() {
+        // 127.0.0.1:1 is (almost certainly) closed.
+        let p = probe("127.0.0.1", 1, Duration::from_millis(500)).await;
+        assert!(!p.reachable && !p.speaks_modbus);
+    }
+
+    #[test]
+    fn parses_device_identification_objects() {
+        let pdu = [
+            0x2B, 0x0E, 0x01, 0x81, 0x00, 0x00, 0x01, // 1 object
+            0x02, 0x05, b'v', b'1', b'.', b'2', b'3', // revision
+        ];
+        let dev = parse_device_id(&pdu).expect("device");
+        assert_eq!(dev.revision.as_deref(), Some("v1.23"));
+        assert!(dev.vendor.is_none());
+    }
+}

werkbank-exec/src/ics/opcua.rs

@@ -0,0 +1,131 @@
+//! Minimal OPC UA reachability probe.
+//!
+//! Speaks just the OPC UA Connection Protocol (UACP) handshake — a `HEL` (Hello)
+//! message, expecting an `ACK` (or `ERR`) reply — to confirm an OPC UA server is
+//! listening (default port 4840). It does **not** open a secure channel or make
+//! service calls; deep analysis of the server's SecurityPolicy / user-token
+//! policies (the common `None` + `Anonymous` misconfiguration) is a follow-on best
+//! done with a full OPC UA stack.
+
+use std::time::Duration;
+
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpStream;
+use tokio::time::timeout;
+
+/// Outcome of an OPC UA handshake probe.
+#[derive(Debug, Default, PartialEq, Eq)]
+pub struct OpcUaProbe {
+    /// A TCP connection to the port was established.
+    pub reachable: bool,
+    /// The endpoint replied to the UACP Hello (`ACK`) or rejected it (`ERR`) —
+    /// either way it speaks OPC UA.
+    pub is_opcua: bool,
+}
+
+/// Probe an OPC UA endpoint with a UACP Hello. Read-only handshake only.
+pub async fn probe(host: &str, port: u16, budget: Duration) -> OpcUaProbe {
+    let mut out = OpcUaProbe::default();
+    let Ok(Ok(mut stream)) = timeout(budget, TcpStream::connect((host, port))).await else {
+        return out;
+    };
+    out.reachable = true;
+
+    let hello = hello_message(&format!("opc.tcp://{host}:{port}"));
+    if timeout(budget, stream.write_all(&hello))
+        .await
+        .ok()
+        .and_then(Result::ok)
+        .is_none()
+    {
+        return out;
+    }
+
+    // Read the 3-byte message type of the reply: ACK (accepted) or ERR (rejected
+    // our hello) both prove the peer speaks the OPC UA connection protocol.
+    let mut mt = [0u8; 3];
+    if timeout(budget, stream.read_exact(&mut mt))
+        .await
+        .ok()
+        .and_then(Result::ok)
+        .is_none()
+    {
+        return out;
+    }
+    if &mt == b"ACK" || &mt == b"ERR" {
+        out.is_opcua = true;
+    }
+    out
+}
+
+/// Build a UACP `HEL` (Hello) message advertising our buffer sizes + endpoint URL.
+fn hello_message(endpoint_url: &str) -> Vec<u8> {
+    let url = endpoint_url.as_bytes();
+    let mut m = Vec::with_capacity(32 + url.len());
+    m.extend_from_slice(b"HELF");
+    m.extend_from_slice(&0u32.to_le_bytes()); // message size — patched below
+    m.extend_from_slice(&0u32.to_le_bytes()); // ProtocolVersion
+    m.extend_from_slice(&65536u32.to_le_bytes()); // ReceiveBufferSize
+    m.extend_from_slice(&65536u32.to_le_bytes()); // SendBufferSize
+    m.extend_from_slice(&0u32.to_le_bytes()); // MaxMessageSize (0 = no limit)
+    m.extend_from_slice(&0u32.to_le_bytes()); // MaxChunkCount
+    m.extend_from_slice(&(url.len() as i32).to_le_bytes()); // EndpointUrl length
+    m.extend_from_slice(url);
+    let size = m.len() as u32;
+    m[4..8].copy_from_slice(&size.to_le_bytes());
+    m
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::net::TcpListener;
+
+    /// A mock OPC UA server that reads the Hello and replies with an `ACK` frame.
+    async fn mock_server() -> std::net::SocketAddr {
+        let listener = TcpListener::bind("127.0.0.1:0").await.expect("bind");
+        let addr = listener.local_addr().expect("addr");
+        tokio::spawn(async move {
+            let (mut sock, _) = listener.accept().await.expect("accept");
+            // Read the Hello header (8 bytes) to learn the size, then drain it.
+            let mut hdr = [0u8; 8];
+            if sock.read_exact(&mut hdr).await.is_err() {
+                return;
+            }
+            let size = u32::from_le_bytes([hdr[4], hdr[5], hdr[6], hdr[7]]) as usize;
+            let mut rest = vec![0u8; size.saturating_sub(8)];
+            let _ = sock.read_exact(&mut rest).await;
+            // Reply: ACK + size + 5 u32 fields.
+            let mut ack = Vec::new();
+            ack.extend_from_slice(b"ACKF");
+            ack.extend_from_slice(&28u32.to_le_bytes());
+            for _ in 0..5 {
+                ack.extend_from_slice(&0u32.to_le_bytes());
+            }
+            let _ = sock.write_all(&ack).await;
+        });
+        addr
+    }
+
+    #[tokio::test]
+    async fn probe_detects_an_opcua_server() {
+        let addr = mock_server().await;
+        let p = probe(&addr.ip().to_string(), addr.port(), Duration::from_secs(2)).await;
+        assert!(p.reachable && p.is_opcua);
+    }
+
+    #[tokio::test]
+    async fn probe_reports_unreachable_for_a_closed_port() {
+        let p = probe("127.0.0.1", 1, Duration::from_millis(500)).await;
+        assert!(!p.reachable && !p.is_opcua);
+    }
+
+    #[test]
+    fn hello_message_is_well_formed() {
+        let m = hello_message("opc.tcp://h:4840");
+        assert_eq!(&m[0..4], b"HELF");
+        // The embedded size equals the actual length.
+        let size = u32::from_le_bytes([m[4], m[5], m[6], m[7]]) as usize;
+        assert_eq!(size, m.len());
+    }
+}

werkbank-exec/src/ics/portscan.rs

@@ -0,0 +1,137 @@
+//! TCP service discovery for a device.
+//!
+//! Connect-scans a curated set of OT/ICS and insecure-management ports and reports
+//! the ones that are open. The deep protocol probes own Modbus (502), OPC UA
+//! (4840) and EtherNet/IP (44818); this surfaces the *rest* of the industrial and
+//! cleartext-management surface (Siemens S7, DNP3, CODESYS programming, Telnet, …).
+
+use std::time::Duration;
+
+use futures_util::future::join_all;
+use tokio::net::TcpStream;
+use tokio::time::timeout;
+
+/// Whether an open port is an industrial protocol or an insecure management service.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PortKind {
+    /// An industrial control protocol (typically unauthenticated).
+    Ics,
+    /// A cleartext management service (credentials/data in the clear).
+    InsecureMgmt,
+}
+
+/// A well-known port worth flagging when open.
+#[derive(Debug, Clone, Copy)]
+pub struct KnownPort {
+    pub port: u16,
+    pub service: &'static str,
+    pub kind: PortKind,
+    pub note: &'static str,
+}
+
+/// The curated scan list. Excludes 502 / 4840 / 44818 — those have dedicated deep
+/// probes (Modbus, OPC UA, EtherNet/IP) that report richer findings.
+pub const KNOWN_PORTS: &[KnownPort] = &[
+    KnownPort {
+        port: 102,
+        service: "S7comm / ISO-TSAP",
+        kind: PortKind::Ics,
+        note: "Siemens S7 PLC communication",
+    },
+    KnownPort {
+        port: 20000,
+        service: "DNP3",
+        kind: PortKind::Ics,
+        note: "SCADA / DNP3",
+    },
+    KnownPort {
+        port: 1911,
+        service: "Niagara Fox",
+        kind: PortKind::Ics,
+        note: "Tridium Niagara building automation",
+    },
+    KnownPort {
+        port: 11740,
+        service: "CODESYS",
+        kind: PortKind::Ics,
+        note: "CODESYS programming protocol",
+    },
+    KnownPort {
+        port: 1962,
+        service: "PCWorx",
+        kind: PortKind::Ics,
+        note: "Phoenix Contact PCWorx",
+    },
+    KnownPort {
+        port: 9600,
+        service: "OMRON FINS",
+        kind: PortKind::Ics,
+        note: "Omron FINS",
+    },
+    KnownPort {
+        port: 789,
+        service: "Red Lion Crimson",
+        kind: PortKind::Ics,
+        note: "Red Lion controllers",
+    },
+    KnownPort {
+        port: 23,
+        service: "Telnet",
+        kind: PortKind::InsecureMgmt,
+        note: "cleartext remote shell",
+    },
+    KnownPort {
+        port: 21,
+        service: "FTP",
+        kind: PortKind::InsecureMgmt,
+        note: "cleartext file transfer",
+    },
+];
+
+/// Connect-scan `ports` on `host` (concurrently) and return those that accept a
+/// TCP connection.
+pub async fn scan<'a>(host: &str, ports: &'a [KnownPort], budget: Duration) -> Vec<&'a KnownPort> {
+    let checks = ports.iter().map(|kp| async move {
+        let open = timeout(budget, TcpStream::connect((host, kp.port)))
+            .await
+            .map(|r| r.is_ok())
+            .unwrap_or(false);
+        (kp, open)
+    });
+    join_all(checks)
+        .await
+        .into_iter()
+        .filter_map(|(kp, open)| open.then_some(kp))
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tokio::net::TcpListener;
+
+    #[tokio::test]
+    async fn scan_reports_only_open_ports() {
+        // Bind one port (open) and pick another that is closed.
+        let listener = TcpListener::bind("127.0.0.1:0").await.expect("bind");
+        let open_port = listener.local_addr().expect("addr").port();
+
+        let ports = [
+            KnownPort {
+                port: open_port,
+                service: "test-open",
+                kind: PortKind::Ics,
+                note: "",
+            },
+            KnownPort {
+                port: 1,
+                service: "test-closed",
+                kind: PortKind::InsecureMgmt,
+                note: "",
+            },
+        ];
+        let found = scan("127.0.0.1", &ports, Duration::from_millis(500)).await;
+        let services: Vec<&str> = found.iter().map(|p| p.service).collect();
+        assert_eq!(services, vec!["test-open"]);
+    }
+}