diff --git a/src/game/char.h b/src/game/char.h
index 68d6be7..9a7b56c 100644
--- a/src/game/char.h
+++ b/src/game/char.h
@@ -1878,6 +1878,7 @@ class CHARACTER : public CEntity, public CFSM, public CHorseRider
 		// by mhh
 		LPITEM*	GetCubeItem() { return m_pointsInstant.pCubeItems; }
 		bool IsCubeOpen () const	{ return (m_pointsInstant.pCubeNpc?true:false); }
+		LPCHARACTER GetCubeNpc() const	{ return m_pointsInstant.pCubeNpc; }
 		void SetCubeNpc(LPCHARACTER npc)	{ m_pointsInstant.pCubeNpc = npc; }
 		bool CanDoCube() const;
 
diff --git a/src/game/char_dragonsoul.cpp b/src/game/char_dragonsoul.cpp
index 5b7bd99..cf64323 100644
--- a/src/game/char_dragonsoul.cpp
+++ b/src/game/char_dragonsoul.cpp
@@ -1,5 +1,6 @@
 #include "stdafx.h"
 #include "char.h"
+#include "utils.h"
 #include "item.h"
 #include "desc.h"
 #include "DragonSoul.h"
@@ -150,5 +151,41 @@ bool CHARACTER::DragonSoul_RefineWindow_Close()
 
 bool CHARACTER::DragonSoul_RefineWindow_CanRefine()
 {
-	return NULL != m_pointsInstant.m_pDragonSoulRefineWindowOpener;
-}
\ No newline at end of file
+	if (NULL == m_pointsInstant.m_pDragonSoulRefineWindowOpener)
+		return false;
+
+	LPENTITY pOpener = m_pointsInstant.m_pDragonSoulRefineWindowOpener;
+	if (!pOpener->IsType(ENTITY_CHARACTER))
+	{
+		RecordAntiCheatViolation("DRAGON_SOUL_REFINE", 6, "state=invalid_opener", true);
+		m_pointsInstant.m_pDragonSoulRefineWindowOpener = NULL;
+		return false;
+	}
+
+	LPCHARACTER npc = (LPCHARACTER)pOpener;
+	if (!npc->IsNPC() || npc == this || npc->GetMapIndex() != GetMapIndex())
+	{
+		char szDetail[160];
+		snprintf(szDetail,
+			 sizeof(szDetail),
+			 "npc=%u map=%ld npc_map=%ld",
+			 npc->GetVID(),
+			 static_cast<long>(GetMapIndex()),
+			 static_cast<long>(npc->GetMapIndex()));
+		RecordAntiCheatViolation("DRAGON_SOUL_REFINE", 8, szDetail, true);
+		m_pointsInstant.m_pDragonSoulRefineWindowOpener = NULL;
+		return false;
+	}
+
+	const int iDistance = DISTANCE_APPROX(GetX() - npc->GetX(), GetY() - npc->GetY());
+	if (iDistance > 2000)
+	{
+		char szDetail[160];
+		snprintf(szDetail, sizeof(szDetail), "npc=%u distance=%d max=%d", npc->GetVID(), iDistance, 2000);
+		RecordAntiCheatViolation("DRAGON_SOUL_REFINE", iDistance > 2800 ? 12 : 4, szDetail, iDistance > 2800);
+		m_pointsInstant.m_pDragonSoulRefineWindowOpener = NULL;
+		return false;
+	}
+
+	return true;
+}
diff --git a/src/game/char_item.cpp b/src/game/char_item.cpp
index dbc592c..236eacc 100644
--- a/src/game/char_item.cpp
+++ b/src/game/char_item.cpp
@@ -43,6 +43,57 @@
 #include "buff_on_attributes.h"
 #include "belt_inventory_helper.h"
 
+namespace
+{
+	constexpr int kRefineNpcMaxDistance = 2000;
+
+	bool ValidateStoredRefineNpc(LPCHARACTER ch, DWORD dwRefineNpcVID, const char* action)
+	{
+		if (!ch)
+			return false;
+
+		if (0 == dwRefineNpcVID)
+		{
+			char szDetail[128];
+			snprintf(szDetail, sizeof(szDetail), "action=%s state=missing", action ? action : "-");
+			ch->RecordAntiCheatViolation("REFINE_NPC", 8, szDetail, true);
+			return false;
+		}
+
+		LPCHARACTER npc = CHARACTER_MANAGER::instance().Find(dwRefineNpcVID);
+		if (!npc || npc == ch || !npc->IsNPC() || npc->GetMapIndex() != ch->GetMapIndex())
+		{
+			char szDetail[160];
+			snprintf(szDetail,
+				 sizeof(szDetail),
+				 "action=%s npc=%u map=%ld npc_map=%ld",
+				 action ? action : "-",
+				 dwRefineNpcVID,
+				 static_cast<long>(ch->GetMapIndex()),
+				 static_cast<long>(npc ? npc->GetMapIndex() : 0));
+			ch->RecordAntiCheatViolation("REFINE_NPC", 8, szDetail, true);
+			return false;
+		}
+
+		const int iDistance = DISTANCE_APPROX(ch->GetX() - npc->GetX(), ch->GetY() - npc->GetY());
+		if (iDistance > kRefineNpcMaxDistance)
+		{
+			char szDetail[160];
+			snprintf(szDetail,
+				 sizeof(szDetail),
+				 "action=%s npc=%u distance=%d max=%d",
+				 action ? action : "-",
+				 dwRefineNpcVID,
+				 iDistance,
+				 kRefineNpcMaxDistance);
+			ch->RecordAntiCheatViolation("REFINE_NPC", iDistance > kRefineNpcMaxDistance + 800 ? 12 : 4, szDetail, iDistance > kRefineNpcMaxDistance + 800);
+			return false;
+		}
+
+		return true;
+	}
+}
+
 const int ITEM_BROKEN_METIN_VNUM = 28960;
 
 // CHANGE_ITEM_ATTRIBUTES
@@ -814,6 +865,12 @@ bool CHARACTER::DoRefine(LPITEM item, bool bMoneyOnly, int iType)
 		ClearRefineMode();
 		return false;
 	}
+
+	if (!ValidateStoredRefineNpc(this, m_dwRefineNPCVID, bMoneyOnly ? "money_only" : "normal"))
+	{
+		ClearRefineMode();
+		return false;
+	}
 	
 	//개량 시간제한 : upgrade_refine_scroll.quest 에서 개량후 5분이내에 일반 개량을 
 	//진행할수 없음
@@ -993,6 +1050,12 @@ bool CHARACTER::DoRefineWithScroll(LPITEM item, int iType)
 		return false;
 	}
 
+	if (!ValidateStoredRefineNpc(this, m_dwRefineNPCVID, "scroll"))
+	{
+		ClearRefineMode();
+		return false;
+	}
+
 	ClearRefineMode();
 
 	//개량 시간제한 : upgrade_refine_scroll.quest 에서 개량후 5분이내에 일반 개량을 
diff --git a/src/game/cube.cpp b/src/game/cube.cpp
index cc340b3..96f2d6b 100644
--- a/src/game/cube.cpp
+++ b/src/game/cube.cpp
@@ -170,6 +170,69 @@ static bool FN_check_valid_npc( WORD vnum )
 	return false;
 }
 
+static void FN_close_cube_session(LPCHARACTER ch)
+{
+	if (!ch)
+		return;
+
+	LPITEM* cube_item = ch->GetCubeItem();
+	for (int i = 0; i < CUBE_MAX_NUM; ++i)
+		cube_item[i] = NULL;
+
+	ch->SetCubeNpc(NULL);
+	ch->ChatPacket(CHAT_TYPE_COMMAND, "cube close");
+}
+
+static bool FN_validate_cube_npc(LPCHARACTER ch, const char* action)
+{
+	if (!ch || !ch->IsCubeOpen())
+		return false;
+
+	LPCHARACTER npc = ch->GetCubeNpc();
+	if (NULL == npc)
+	{
+		char szDetail[128];
+		snprintf(szDetail, sizeof(szDetail), "action=%s state=missing", action ? action : "-");
+		ch->RecordAntiCheatViolation("CUBE_NPC", 6, szDetail, true);
+		FN_close_cube_session(ch);
+		return false;
+	}
+
+	if (!npc->IsNPC() || !FN_check_valid_npc(npc->GetRaceNum()) || npc->GetMapIndex() != ch->GetMapIndex())
+	{
+		char szDetail[160];
+		snprintf(szDetail,
+			 sizeof(szDetail),
+			 "action=%s npc=%u map=%ld npc_map=%ld race=%u",
+			 action ? action : "-",
+			 npc->GetVID(),
+			 static_cast<long>(ch->GetMapIndex()),
+			 static_cast<long>(npc->GetMapIndex()),
+			 npc->GetRaceNum());
+		ch->RecordAntiCheatViolation("CUBE_NPC", 8, szDetail, true);
+		FN_close_cube_session(ch);
+		return false;
+	}
+
+	const long distance = DISTANCE_APPROX(ch->GetX() - npc->GetX(), ch->GetY() - npc->GetY());
+	if (distance >= CUBE_MAX_DISTANCE)
+	{
+		char szDetail[160];
+		snprintf(szDetail,
+			 sizeof(szDetail),
+			 "action=%s npc=%u distance=%ld max=%d",
+			 action ? action : "-",
+			 npc->GetVID(),
+			 distance,
+			 CUBE_MAX_DISTANCE);
+		ch->RecordAntiCheatViolation("CUBE_NPC", distance >= CUBE_MAX_DISTANCE + 800 ? 12 : 4, szDetail, distance >= CUBE_MAX_DISTANCE + 800);
+		FN_close_cube_session(ch);
+		return false;
+	}
+
+	return true;
+}
+
 // 큐브데이타가 올바르게 초기화 되었는지 체크한다.
 static bool FN_check_cube_data (CUBE_DATA *cube_data)
 {
@@ -486,12 +549,10 @@ static bool FN_update_cube_status(LPCHARACTER ch)
 	if (NULL == ch)
 		return false;
 
-	if (!ch->IsCubeOpen())
+	if (!FN_validate_cube_npc(ch, "status"))
 		return false;
 
-	LPCHARACTER	npc = ch->GetQuestNPC();
-	if (NULL == npc)
-		return false;
+	LPCHARACTER	npc = ch->GetCubeNpc();
 
 	CUBE_DATA* cube = FN_find_cube(ch->GetCubeItem(), npc->GetRaceNum());
 
@@ -525,11 +586,10 @@ bool Cube_make (LPCHARACTER ch)
 		return false;
 	}
 
-	npc = ch->GetQuestNPC();
-	if (NULL == npc)
-	{
+	if (!FN_validate_cube_npc(ch, "make"))
 		return false;
-	}
+
+	npc = ch->GetCubeNpc();
 
 	items = ch->GetCubeItem();
 	cube_proto = FN_find_cube(items, npc->GetRaceNum());
@@ -613,6 +673,9 @@ void Cube_add_item (LPCHARACTER ch, int cube_index, int inven_index)
 
 	RETURN_IF_CUBE_IS_NOT_OPENED(ch);
 
+	if (!FN_validate_cube_npc(ch, "add_item"))
+		return;
+
 	if (inven_index<0 || INVENTORY_MAX_NUM<=inven_index)
 		return;
 	if (cube_index<0 || CUBE_MAX_NUM<=cube_index)
@@ -655,6 +718,9 @@ void Cube_delete_item (LPCHARACTER ch, int cube_index)
 
 	RETURN_IF_CUBE_IS_NOT_OPENED(ch);
 
+	if (!FN_validate_cube_npc(ch, "delete_item"))
+		return;
+
 	if (cube_index<0 || CUBE_MAX_NUM<=cube_index)	return;
 
 	cube_item = ch->GetCubeItem();
@@ -876,10 +942,11 @@ void Cube_request_result_list(LPCHARACTER ch)
 {
 	RETURN_IF_CUBE_IS_NOT_OPENED(ch);
 
-	LPCHARACTER	npc = ch->GetQuestNPC();
-	if (NULL == npc)
+	if (!FN_validate_cube_npc(ch, "result_list"))
 		return;
 
+	LPCHARACTER	npc = ch->GetCubeNpc();
+
 	DWORD npcVNUM = npc->GetRaceNum();
 	size_t resultCount = 0;
 
@@ -930,10 +997,11 @@ void Cube_request_material_info(LPCHARACTER ch, int requestStartIndex, int reque
 {
 	RETURN_IF_CUBE_IS_NOT_OPENED(ch);
 
-	LPCHARACTER	npc = ch->GetQuestNPC();
-	if (NULL == npc)
+	if (!FN_validate_cube_npc(ch, "material_info"))
 		return;
 
+	LPCHARACTER	npc = ch->GetCubeNpc();
+
 	DWORD npcVNUM = npc->GetRaceNum();
 	std::string materialInfoText = "";