docs(adr): ADR-0095, run Sliver as the range C2 on the attack VM

README.md

@@ -129,7 +129,7 @@ documents for different readers.
   at all. Every pinned digest is also scanned weekly for fixable HIGH and
   CRITICAL CVEs, and each image with findings has an open issue until a scan
   finds it clean.
-- **Documented decisions and runbooks.** 94 ADRs covering what was chosen
+- **Documented decisions and runbooks.** 95 ADRs covering what was chosen
   and what was rejected — including the costs accepted knowingly; 49
   runbooks for the operations that are easy to get wrong at 1am, one of which
   is the handover page a successor reads first. Every critical alert links to
@@ -224,7 +224,7 @@ inbound passes may still reach it. Data flow and the maintained Mermaid topology
 │   ├── architecture.md  network.md  hardware.md
 │   ├── observability.md  security.md  roadmap.md  changelog.md
 │   ├── diagrams/             # the network diagram (SVG) and its predecessors
-│   ├── adr/                  # 94 ADRs — architecture decision records
+│   ├── adr/                  # 95 ADRs — architecture decision records
 │   ├── exercises/            # purple-team exercise records — see its README
 │   └── runbooks/             # 49 runbooks; successor-handover.md is the front door
 └── Makefile                  # make help

docs/adr/0095-run-sliver-as-the-range-c2-on-the-attack-vm.md

@@ -0,0 +1,106 @@
+# ADR-0095: Run Sliver as the range C2 on the attack VM
+
+**Status:** Accepted · 2026-10
+
+## Context
+
+[ADR-0007](0007-defensive-estate-and-offensive-range.md) says `ifrit` "holds
+C2 and attack tooling", and [ADR-0017](0017-buy-ifrit-for-iops-and-keep-the-range-disposable.md)
+sizes its memory against "a Kali VM with BloodHound and its Neo4j alongside a
+C2 server". Neither names the C2. The playground runbook's §5 builds the attack
+VM and references "the C2 operator's interface" without saying what serves it.
+This picks one, so the runbook and the first exercises have something concrete
+to build against rather than a placeholder.
+
+The purpose fixes the requirement, and it is not the attacker's. The range
+exists so the defended estate — the Windows domain on `Saruman`, watched by
+Wazuh, Velociraptor and Zeek — **experiences** a real command-and-control
+channel and the SOC gets to catch it
+([ADR-0007](0007-defensive-estate-and-offensive-range.md), measured in the
+exercise log under `docs/exercises/`). So the C2 is chosen to be
+representative of what the SOC must detect, inspectable while it runs, and
+cheap to stand up and tear down on a box that is powered off between sessions.
+Evasion is explicitly not a goal here: the aim is to generate known, labelled
+activity and measure whether the estate sees it, not to win against it.
+
+What the choice is between, among the maintained open-source frameworks:
+
+- **Sliver** (BishopFox). Single Go binary for the server and a single binary
+  for the operator client. Cross-platform implants, mTLS / HTTP(S) / DNS / WireGuard
+  transports, multiplayer, and a scriptable console. Actively maintained, and
+  well represented in public detection content, so expected signatures exist
+  to test against.
+- **Mythic** (its own project). A framework of Docker containers with a web UI
+  and pluggable agents. More moving parts, more capable, and heavier to run.
+- **Metasploit's own session handler.** Already in Kali, familiar, and its
+  traffic is the most heavily signatured of all — but it is a weaker model of
+  a modern C2's transports and long-haul beaconing.
+- **Havoc**, **Covenant**, and the commercial frameworks. Each is either less
+  maintained, .NET-centric, or costs money for no gain the lab needs.
+
+## Decision
+
+**The range C2 is Sliver, run on the attack VM, reached only from the operator
+workstation.**
+
+- **Sliver** is the default framework. One server binary on the attack VM, the
+  operator client over Sliver's own mTLS. It is a single VM state to snapshot
+  and revert with the rest of the range, which suits a disposable playground
+  that `ifrit` powers off between sessions.
+- **It runs on the attack VM, inside the range**, which already shares VLAN 30's
+  broadcast domain with the estate by [ADR-0014](0014-put-ifrit-on-imaginationlan-and-give-the-targets-no-route.md).
+  The implant's callbacks from a domain host to the attack VM traverse exactly
+  the segment the SOC and Zeek watch, which is the point.
+- **No new firewall rule, and nothing reaches the house.** The C2 listener and
+  its implants live within the lab segment and the routeless range bridge. The
+  operator reaches the Sliver console the way the range is already driven —
+  from a Hicks workstation over the existing `50 → 30` path, which
+  [ADR-0014](0014-put-ifrit-on-imaginationlan-and-give-the-targets-no-route.md)
+  names as carrying "the C2 operator's interface". It is not driven from
+  `garuda`, the analyst workstation, which is defensive-only and watches the
+  attack rather than mounting it
+  ([ADR-0091](0091-put-a-kali-purple-analyst-workstation-on-saruman.md)). The
+  console is not reached from a management host, and the C2 never remote-writes,
+  phones home off the estate, or opens a path *into* the house.
+- **Mythic is the named fallback**, not a second standing install. If an
+  exercise needs an agent or a transport Sliver does not offer, that exercise's
+  file records why and stands Mythic up on its own guest for the run. The
+  default stays one framework so the baseline the SOC is tuned against does not
+  drift.
+- **Describe, do not publish.** Per [`security.md`](../security.md#what-this-repository-deliberately-does-not-publish)
+  and the `docs/exercises/` rules, exercise files name the
+  framework, the transport and the technique by ATT&CK ID. They carry no
+  profiles, no generated implants, and no operator configuration or keys.
+
+## Consequences
+
+- The playground runbook's §5 and the first exercises have a concrete C2 to
+  name. "Stand up the C2" becomes "install Sliver on the attack VM."
+- Detections are tuned against one framework's defaults first, which is the
+  honest starting baseline: a known channel the estate either catches or does
+  not. Later exercises can vary the transport (mTLS, then HTTPS, then DNS) and
+  record how each shifts what Zeek and Suricata see — the measurable progression
+  the exercise log is built for.
+- Choosing the well-signatured framework on purpose means an early *miss* is a
+  real gap in the estate's visibility, not an artifact of an exotic tool. That
+  is the more useful failure.
+- Sliver on the attack VM adds no RAM beyond what [ADR-0017](0017-buy-ifrit-for-iops-and-keep-the-range-disposable.md)
+  already counted for "a C2 server"; BloodHound still runs on `eden`, off the
+  attacker's host.
+- The lab gains a second framework's worth of upkeep only when an exercise
+  calls for Mythic, and only for that run. The standing surface stays small.
+
+## Alternatives considered
+
+- **Mythic as the default.** Rejected as the standing choice for the weight:
+  a container stack with a web UI is more to run, snapshot and revert on a box
+  meant to be disposable, for capability the first year of exercises does not
+  need. Kept as the fallback for the exercise that outgrows Sliver.
+- **Metasploit's handler as the C2.** Rejected as the representative channel:
+  it is already in Kali and fine for a quick session, but it models a modern
+  beaconing C2 poorly, and leaning on the single most-signatured handler would
+  make the estate look more capable than it is.
+- **No decision; pick per exercise.** Rejected because a moving baseline cannot
+  be measured. One default framework, tuned against and recorded, is what makes
+  "the SOC caught more this quarter than last" a true statement rather than a
+  comparison of different tools.