diff --git a/accounts/manager.go b/accounts/manager.go
index 96ca298fc5..3cf3422e77 100644
--- a/accounts/manager.go
+++ b/accounts/manager.go
@@ -24,9 +24,18 @@ import (
 	"github.com/ethereum/go-ethereum/event"
 )
 
+// Config contains the settings of the global account manager.
+//
+// TODO(rjl493456442, karalabe, holiman): Get rid of this when account management
+// is removed in favor of Clef.
+type Config struct {
+	InsecureUnlockAllowed bool // Whether account unlocking in insecure environment is allowed
+}
+
 // Manager is an overarching account manager that can communicate with various
 // backends for signing transactions.
 type Manager struct {
+	config   *Config                    // Global account manager configurations
 	backends map[reflect.Type][]Backend // Index of backends currently registered
 	updaters []event.Subscription       // Wallet update subscriptions for all backends
 	updates  chan WalletEvent           // Subscription sink for backend wallet changes
@@ -40,7 +49,7 @@ type Manager struct {
 
 // NewManager creates a generic account manager to sign transaction via various
 // supported backends.
-func NewManager(backends ...Backend) *Manager {
+func NewManager(config *Config, backends ...Backend) *Manager {
 	// Retrieve the initial list of wallets from the backends and sort by URL
 	var wallets []Wallet
 	for _, backend := range backends {
@@ -55,6 +64,7 @@ func NewManager(backends ...Backend) *Manager {
 	}
 	// Assemble the account manager and return
 	am := &Manager{
+		config:   config,
 		backends: make(map[reflect.Type][]Backend),
 		updaters: subs,
 		updates:  updates,
@@ -77,6 +87,11 @@ func (am *Manager) Close() error {
 	return <-errc
 }
 
+// Config returns the configuration of account manager.
+func (am *Manager) Config() *Config {
+	return am.config
+}
+
 // update is the wallet event loop listening for notifications from the backends
 // and updating the cache of wallets.
 func (am *Manager) update() {
diff --git a/cmd/geth/accountcmd.go b/cmd/geth/accountcmd.go
index 071be85397..940290899c 100644
--- a/cmd/geth/accountcmd.go
+++ b/cmd/geth/accountcmd.go
@@ -205,7 +205,7 @@ func accountList(ctx *cli.Context) error {
 }
 
 // tries unlocking the specified account a few times.
-func unlockAccount(ctx *cli.Context, ks *keystore.KeyStore, address string, i int, passwords []string) (accounts.Account, string) {
+func unlockAccount(ks *keystore.KeyStore, address string, i int, passwords []string) (accounts.Account, string) {
 	account, err := utils.MakeAddress(ks, address)
 	if err != nil {
 		utils.Fatalf("Could not list accounts: %v", err)
@@ -326,7 +326,7 @@ func accountUpdate(ctx *cli.Context) error {
 	ks := stack.AccountManager().Backends(keystore.KeyStoreType)[0].(*keystore.KeyStore)
 
 	for _, addr := range ctx.Args() {
-		account, oldPassword := unlockAccount(ctx, ks, addr, 0, nil)
+		account, oldPassword := unlockAccount(ks, addr, 0, nil)
 		newPassword := getPassPhrase("Please give a new password. Do not forget this password.", true, 0, nil)
 		if err := ks.Update(account, oldPassword, newPassword); err != nil {
 			utils.Fatalf("Could not update the account: %v", err)
diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index 3d96de3128..1963a1a7f8 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -57,6 +57,7 @@ var (
 		utils.IdentityFlag,
 		utils.UnlockedAccountFlag,
 		utils.PasswordFileFlag,
+		utils.InsecureUnlockAllowedFlag,
 		utils.BootnodesFlag,
 		utils.BootnodesV4Flag,
 		utils.BootnodesV5Flag,
@@ -298,16 +299,8 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 	utils.StartNode(stack)
 
 	// Unlock any account specifically requested
-	if keystores := stack.AccountManager().Backends(keystore.KeyStoreType); len(keystores) > 0 {
-		ks := keystores[0].(*keystore.KeyStore)
-		passwords := utils.MakePasswordList(ctx)
-		unlocks := strings.Split(ctx.GlobalString(utils.UnlockedAccountFlag.Name), ",")
-		for i, account := range unlocks {
-			if trimmed := strings.TrimSpace(account); trimmed != "" {
-				unlockAccount(ctx, ks, trimmed, i, passwords)
-			}
-		}
-	}
+	unlockAccounts(ctx, stack)
+
 	// Register wallet event handlers to open and auto-derive wallets
 	events := make(chan accounts.WalletEvent, 16)
 	stack.AccountManager().Subscribe(events)
@@ -401,3 +394,28 @@ func startNode(ctx *cli.Context, stack *node.Node) {
 		}
 	}
 }
+
+// unlockAccounts unlocks any account specifically requested.
+func unlockAccounts(ctx *cli.Context, stack *node.Node) {
+	var unlocks []string
+	inputs := strings.Split(ctx.GlobalString(utils.UnlockedAccountFlag.Name), ",")
+	for _, input := range inputs {
+		if trimmed := strings.TrimSpace(input); trimmed != "" {
+			unlocks = append(unlocks, trimmed)
+		}
+	}
+	// Short circuit if there is no account to unlock.
+	if len(unlocks) == 0 {
+		return
+	}
+	// If insecure account unlocking is not allowed if node's APIs are exposed to external.
+	// Print warning log to user and skip unlocking.
+	if !stack.Config().InsecureUnlockAllowed && stack.Config().ExtRPCEnabled() {
+		utils.Fatalf("Account unlock with HTTP access is forbidden!")
+	}
+	ks := stack.AccountManager().Backends(keystore.KeyStoreType)[0].(*keystore.KeyStore)
+	passwords := utils.MakePasswordList(ctx)
+	for i, account := range unlocks {
+		unlockAccount(ks, account, i, passwords)
+	}
+}
diff --git a/cmd/geth/usage.go b/cmd/geth/usage.go
index f1fb22f18e..6d039ba040 100644
--- a/cmd/geth/usage.go
+++ b/cmd/geth/usage.go
@@ -148,6 +148,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.UnlockedAccountFlag,
 			utils.PasswordFileFlag,
 			utils.ExternalSignerFlag,
+			utils.InsecureUnlockAllowedFlag,
 		},
 	},
 	{
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 2ce3a88014..f6e4288692 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -444,6 +444,10 @@ var (
 		Name:  "vmdebug",
 		Usage: "Record information useful for VM and contract debugging",
 	}
+	InsecureUnlockAllowedFlag = cli.BoolFlag{
+		Name:  "allow-insecure-unlock",
+		Usage: "Allow insecure account unlocking when account-related RPCs are exposed by http",
+	}
 	// Logging and debug settings
 	EthStatsURLFlag = cli.StringFlag{
 		Name:  "ethstats",
@@ -1130,6 +1134,9 @@ func SetNodeConfig(ctx *cli.Context, cfg *node.Config) {
 	if ctx.GlobalIsSet(NoUSBFlag.Name) {
 		cfg.NoUSB = ctx.GlobalBool(NoUSBFlag.Name)
 	}
+	if ctx.GlobalIsSet(InsecureUnlockAllowedFlag.Name) {
+		cfg.InsecureUnlockAllowed = ctx.GlobalBool(InsecureUnlockAllowedFlag.Name)
+	}
 }
 
 func setDataDir(ctx *cli.Context, cfg *node.Config) {
diff --git a/eth/api_backend.go b/eth/api_backend.go
index 7e90f80101..29ce19e28f 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -38,8 +38,9 @@ import (
 
 // EthAPIBackend implements ethapi.Backend for full nodes
 type EthAPIBackend struct {
-	eth *Ethereum
-	gpo *gasprice.Oracle
+	extRPCEnabled bool
+	eth           *Ethereum
+	gpo           *gasprice.Oracle
 }
 
 // ChainConfig returns the active chain configuration.
@@ -213,6 +214,10 @@ func (b *EthAPIBackend) AccountManager() *accounts.Manager {
 	return b.eth.AccountManager()
 }
 
+func (b *EthAPIBackend) ExtRPCEnabled() bool {
+	return b.extRPCEnabled
+}
+
 func (b *EthAPIBackend) BloomStatus() (uint64, uint64) {
 	sections, _, _ := b.eth.bloomIndexer.Sections()
 	return params.BloomBitsBlocks, sections
diff --git a/eth/backend.go b/eth/backend.go
index af963fa495..b13cb10289 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -197,7 +197,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 	eth.miner = miner.New(eth, chainConfig, eth.EventMux(), eth.engine, config.MinerRecommit, config.MinerGasFloor, config.MinerGasCeil, eth.isLocalBlock)
 	eth.miner.SetExtra(makeExtraData(config.MinerExtraData))
 
-	eth.APIBackend = &EthAPIBackend{eth, nil}
+	eth.APIBackend = &EthAPIBackend{ctx.ExtRPCEnabled(), eth, nil}
 	gpoParams := config.GPO
 	if gpoParams.Default == nil {
 		gpoParams.Default = config.MinerGasPrice
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index b6f01b7539..e5a8124b1f 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -317,7 +317,14 @@ func (s *PrivateAccountAPI) ImportRawKey(privkey string, password string) (commo
 // UnlockAccount will unlock the account associated with the given address with
 // the given password for duration seconds. If duration is nil it will use a
 // default of 300 seconds. It returns an indication if the account was unlocked.
-func (s *PrivateAccountAPI) UnlockAccount(addr common.Address, password string, duration *uint64) (bool, error) {
+func (s *PrivateAccountAPI) UnlockAccount(ctx context.Context, addr common.Address, password string, duration *uint64) (bool, error) {
+	// When the API is exposed by external RPC(http, ws etc), unless the user
+	// explicitly specifies to allow the insecure account unlocking, otherwise
+	// it is disabled.
+	if s.b.ExtRPCEnabled() && !s.b.AccountManager().Config().InsecureUnlockAllowed {
+		return false, errors.New("account unlock with HTTP access is forbidden")
+	}
+
 	const max = uint64(time.Duration(math.MaxInt64) / time.Second)
 	var d time.Duration
 	if duration == nil {
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index e23ee03b15..e88207f87d 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -44,6 +44,7 @@ type Backend interface {
 	ChainDb() ethdb.Database
 	EventMux() *event.TypeMux
 	AccountManager() *accounts.Manager
+	ExtRPCEnabled() bool
 
 	// BlockChain API
 	SetHead(number uint64)
diff --git a/les/api_backend.go b/les/api_backend.go
index 7531396235..8b03979a29 100644
--- a/les/api_backend.go
+++ b/les/api_backend.go
@@ -39,8 +39,9 @@ import (
 )
 
 type LesApiBackend struct {
-	eth *LightEthereum
-	gpo *gasprice.Oracle
+	extRPCEnabled bool
+	eth           *LightEthereum
+	gpo           *gasprice.Oracle
 }
 
 func (b *LesApiBackend) ChainConfig() *params.ChainConfig {
@@ -187,6 +188,10 @@ func (b *LesApiBackend) AccountManager() *accounts.Manager {
 	return b.eth.accountManager
 }
 
+func (b *LesApiBackend) ExtRPCEnabled() bool {
+	return b.extRPCEnabled
+}
+
 func (b *LesApiBackend) BloomStatus() (uint64, uint64) {
 	if b.eth.bloomIndexer == nil {
 		return 0, 0
diff --git a/les/backend.go b/les/backend.go
index f0f8a6a6ec..944e7695d2 100644
--- a/les/backend.go
+++ b/les/backend.go
@@ -166,7 +166,7 @@ func New(ctx *node.ServiceContext, config *eth.Config) (*LightEthereum, error) {
 		log.Warn("Ultra light client is enabled", "trustedNodes", len(leth.protocolManager.ulc.trustedKeys), "minTrustedFraction", leth.protocolManager.ulc.minTrustedFraction)
 		leth.blockchain.DisableCheckFreq()
 	}
-	leth.ApiBackend = &LesApiBackend{leth, nil}
+	leth.ApiBackend = &LesApiBackend{ctx.ExtRPCEnabled(), leth, nil}
 
 	gpoParams := config.GPO
 	if gpoParams.Default == nil {
diff --git a/node/config.go b/node/config.go
index 2f871e478b..46876c1578 100644
--- a/node/config.go
+++ b/node/config.go
@@ -88,6 +88,9 @@ type Config struct {
 	// scrypt KDF at the expense of security.
 	UseLightweightKDF bool `toml:",omitempty"`
 
+	// InsecureUnlockAllowed allows user to unlock accounts in unsafe http environment.
+	InsecureUnlockAllowed bool `toml:",omitempty"`
+
 	// NoUSB disables hardware wallet monitoring and connectivity.
 	NoUSB bool `toml:",omitempty"`
 
@@ -106,29 +109,6 @@ type Config struct {
 	// for ephemeral nodes).
 	HTTPPort int `toml:",omitempty"`
 
-	// GraphQLHost is the host interface on which to start the GraphQL server. If this
-	// field is empty, no GraphQL API endpoint will be started.
-	GraphQLHost string `toml:",omitempty"`
-
-	// GraphQLPort is the TCP port number on which to start the GraphQL server. The
-	// default zero value is/ valid and will pick a port number randomly (useful
-	// for ephemeral nodes).
-	GraphQLPort int `toml:",omitempty"`
-
-	// GraphQLCors is the Cross-Origin Resource Sharing header to send to requesting
-	// clients. Please be aware that CORS is a browser enforced security, it's fully
-	// useless for custom HTTP clients.
-	GraphQLCors []string `toml:",omitempty"`
-
-	// GraphQLVirtualHosts is the list of virtual hostnames which are allowed on incoming requests.
-	// This is by default {'localhost'}. Using this prevents attacks like
-	// DNS rebinding, which bypasses SOP by simply masquerading as being within the same
-	// origin. These attacks do not utilize CORS, since they are not cross-domain.
-	// By explicitly checking the Host-header, the server will not allow requests
-	// made against the server with a malicious host domain.
-	// Requests using ip address directly are not affected
-	GraphQLVirtualHosts []string `toml:",omitempty"`
-
 	// HTTPCors is the Cross-Origin Resource Sharing header to send to requesting
 	// clients. Please be aware that CORS is a browser enforced security, it's fully
 	// useless for custom HTTP clients.
@@ -178,6 +158,29 @@ type Config struct {
 	// private APIs to untrusted users is a major security risk.
 	WSExposeAll bool `toml:",omitempty"`
 
+	// GraphQLHost is the host interface on which to start the GraphQL server. If this
+	// field is empty, no GraphQL API endpoint will be started.
+	GraphQLHost string `toml:",omitempty"`
+
+	// GraphQLPort is the TCP port number on which to start the GraphQL server. The
+	// default zero value is/ valid and will pick a port number randomly (useful
+	// for ephemeral nodes).
+	GraphQLPort int `toml:",omitempty"`
+
+	// GraphQLCors is the Cross-Origin Resource Sharing header to send to requesting
+	// clients. Please be aware that CORS is a browser enforced security, it's fully
+	// useless for custom HTTP clients.
+	GraphQLCors []string `toml:",omitempty"`
+
+	// GraphQLVirtualHosts is the list of virtual hostnames which are allowed on incoming requests.
+	// This is by default {'localhost'}. Using this prevents attacks like
+	// DNS rebinding, which bypasses SOP by simply masquerading as being within the same
+	// origin. These attacks do not utilize CORS, since they are not cross-domain.
+	// By explicitly checking the Host-header, the server will not allow requests
+	// made against the server with a malicious host domain.
+	// Requests using ip address directly are not affected
+	GraphQLVirtualHosts []string `toml:",omitempty"`
+
 	// Logger is a custom logger to use with the p2p.Server.
 	Logger log.Logger `toml:",omitempty"`
 
@@ -270,6 +273,12 @@ func DefaultWSEndpoint() string {
 	return config.WSEndpoint()
 }
 
+// ExtRPCEnabled returns the indicator whether node enables the external
+// RPC(http, ws or graphql).
+func (c *Config) ExtRPCEnabled() bool {
+	return c.HTTPHost != "" || c.WSHost != "" || c.GraphQLHost != ""
+}
+
 // NodeName returns the devp2p node identifier.
 func (c *Config) NodeName() string {
 	name := c.name()
@@ -497,7 +506,7 @@ func makeAccountManager(conf *Config) (*accounts.Manager, string, error) {
 		}
 	}
 
-	return accounts.NewManager(backends...), ephemeral, nil
+	return accounts.NewManager(&accounts.Config{InsecureUnlockAllowed: conf.InsecureUnlockAllowed}, backends...), ephemeral, nil
 }
 
 var warnLock sync.Mutex
diff --git a/node/node.go b/node/node.go
index bd031bd0fe..f4c7d8c726 100644
--- a/node/node.go
+++ b/node/node.go
@@ -251,6 +251,11 @@ func (n *Node) Start() error {
 	return nil
 }
 
+// Config returns the configuration of node.
+func (n *Node) Config() *Config {
+	return n.config
+}
+
 func (n *Node) openDataDir() error {
 	if n.config.DataDir == "" {
 		return nil // ephemeral
diff --git a/node/service.go b/node/service.go
index 4f6cb66769..24f8097435 100644
--- a/node/service.go
+++ b/node/service.go
@@ -68,6 +68,12 @@ func (ctx *ServiceContext) Service(service interface{}) error {
 	return ErrServiceUnknown
 }
 
+// ExtRPCEnabled returns the indicator whether node enables the external
+// RPC(http, ws or graphql).
+func (ctx *ServiceContext) ExtRPCEnabled() bool {
+	return ctx.config.ExtRPCEnabled()
+}
+
 // ServiceConstructor is the function signature of the constructors needed to be
 // registered for service instantiation.
 type ServiceConstructor func(ctx *ServiceContext) (Service, error)
diff --git a/signer/core/api.go b/signer/core/api.go
index 184b903103..9da6ee2a23 100644
--- a/signer/core/api.go
+++ b/signer/core/api.go
@@ -139,7 +139,8 @@ func StartClefAccountManager(ksLocation string, nousb, lightKDF bool) *accounts.
 			log.Debug("Trezor support enabled")
 		}
 	}
-	return accounts.NewManager(backends...)
+	// Clef doesn't allow insecure http account unlock.
+	return accounts.NewManager(&accounts.Config{InsecureUnlockAllowed: false}, backends...)
 }
 
 // MetadataFromContext extracts Metadata from a given context.Context