diff --git a/backend/app/api/c2.py b/backend/app/api/c2.py
index 745637c..3f2a131 100644
--- a/backend/app/api/c2.py
+++ b/backend/app/api/c2.py
@@ -84,7 +84,7 @@ def upsert_c2_config(eid: int):
     if not parsed.hostname:
         return jsonify({"error": "url must contain a hostname"}), 400
 
-    verify_tls = data.get("verify_tls", True)
+    verify_tls = data.get("verify_tls", False)
     if not isinstance(verify_tls, bool):
         return jsonify({"error": "verify_tls must be a boolean"}), 400
 
diff --git a/backend/app/models/c2_config.py b/backend/app/models/c2_config.py
index 4015a13..e3876a0 100644
--- a/backend/app/models/c2_config.py
+++ b/backend/app/models/c2_config.py
@@ -19,7 +19,7 @@ class C2Config(db.Model):  # type: ignore[name-defined]
     )
     url = db.Column(db.Text, nullable=False)
     api_token_encrypted = db.Column(db.Text, nullable=False)
-    verify_tls = db.Column(db.Boolean, nullable=False, default=True)
+    verify_tls = db.Column(db.Boolean, nullable=False, default=False)
     created_at = db.Column(
         db.DateTime, nullable=False, default=lambda: datetime.now(UTC)
     )
diff --git a/backend/app/services/c2/factory.py b/backend/app/services/c2/factory.py
index 0c46370..75cce7a 100644
--- a/backend/app/services/c2/factory.py
+++ b/backend/app/services/c2/factory.py
@@ -6,7 +6,7 @@ import os
 from backend.app.services.c2.adapter import C2Adapter
 
 
-def get_adapter(url: str, api_token: str, verify_tls: bool = True) -> C2Adapter:
+def get_adapter(url: str, api_token: str, verify_tls: bool = False) -> C2Adapter:
     """Return the correct C2Adapter based on MIMIC_C2_ADAPTER (default: mythic)."""
     adapter_name = os.environ.get("MIMIC_C2_ADAPTER", "mythic").lower()
 
diff --git a/backend/app/services/c2/mythic.py b/backend/app/services/c2/mythic.py
index 2eec290..c430afa 100644
--- a/backend/app/services/c2/mythic.py
+++ b/backend/app/services/c2/mythic.py
@@ -15,6 +15,8 @@ from __future__ import annotations
 from datetime import datetime
 
 import requests
+import urllib3
+from urllib3.exceptions import InsecureRequestWarning
 
 from backend.app.services.c2.adapter import (
     C2Adapter,
@@ -113,10 +115,14 @@ query GetTaskOutput($display_id: Int!) {
 class MythicAdapter(C2Adapter):
     """Real Mythic 3.x adapter using GraphQL over HTTP."""
 
-    def __init__(self, url: str, api_token: str, verify_tls: bool = True) -> None:
+    def __init__(self, url: str, api_token: str, verify_tls: bool = False) -> None:
         self._url = url.rstrip("/") + "/graphql"
         self._token = api_token
         self._verify = verify_tls
+        if not verify_tls:
+            # Lab/red-team Mythic instances commonly use self-signed certs.
+            # Suppress urllib3 warnings once per process when verification is off.
+            urllib3.disable_warnings(InsecureRequestWarning)
 
     def _headers(self) -> dict[str, str]:
         return {
diff --git a/backend/migrations/versions/0008_c2_verify_tls_default_false.py b/backend/migrations/versions/0008_c2_verify_tls_default_false.py
new file mode 100644
index 0000000..33e1dc0
--- /dev/null
+++ b/backend/migrations/versions/0008_c2_verify_tls_default_false.py
@@ -0,0 +1,33 @@
+"""flip c2_config.verify_tls server_default to false
+
+Revision ID: 0008_c2_verify_tls_default_false
+Revises: 0007
+Create Date: 2026-06-21 00:00:00.000000
+"""
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0008_c2_verify_tls_default_false"
+down_revision = "0007"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    with op.batch_alter_table("c2_config") as batch_op:
+        batch_op.alter_column(
+            "verify_tls",
+            existing_type=sa.Boolean(),
+            existing_nullable=False,
+            server_default=sa.false(),
+        )
+
+
+def downgrade() -> None:
+    with op.batch_alter_table("c2_config") as batch_op:
+        batch_op.alter_column(
+            "verify_tls",
+            existing_type=sa.Boolean(),
+            existing_nullable=False,
+            server_default=sa.true(),
+        )
diff --git a/backend/tests/test_c2_config.py b/backend/tests/test_c2_config.py
index fd2c617..d8f4235 100644
--- a/backend/tests/test_c2_config.py
+++ b/backend/tests/test_c2_config.py
@@ -206,13 +206,13 @@ def test_get_config_returns_has_token_not_cleartext(
     assert "s3cr3t" not in str(body)
 
 
-def test_get_config_verify_tls_default_true(
+def test_get_config_verify_tls_default_false(
     client: FlaskClient, admin_token: str
 ) -> None:
     eng = _make_engagement(client, admin_token)
-    _put_config(client, admin_token, eng["id"])
+    _put_config(client, admin_token, eng["id"], verify_tls=False)
     resp = client.get(f"/api/engagements/{eng['id']}/c2-config", headers=_h(admin_token))
-    assert resp.get_json()["verify_tls"] is True
+    assert resp.get_json()["verify_tls"] is False
 
 
 # ---------------------------------------------------------------------------