BRLY-2025-018

SMRAM memory contents leak / information disclosure vulnerability in SMM module (SMRAM read).

Public Disclosure Date: Jul 29, 2025

CVE ID

CVE-2025-4426

Vendors Affected

Lenovo

Products Affected

ideacentre-aio-3-24arr9+2 more

Summary

BINARLY REsearch team has discovered an SMRAM read vulnerability in Lenovo device firmware that could allow a potential attacker to read SMRAM content.

Potential Impact

An attacker can exploit this vulnerability to elevate privileges from ring 0 to ring -2, and read SMRAM content (that can help to execute arbitrary code in System Management Mode - an evironment more privileged than operating system (OS) and completely isolated from it). Running arbitrary code in SMM also bypasses SMM-based SPI flash protections against modification, which can help an attacker to install a firmware backdoor/implant. Such malicious code in the firmware could persist through operating system reinstallations. In addition, this vulnerability could potentially be used by malicious actors to bypass security mechanisms provided by UEFI firmware, such as Secure Boot and some types of memory isolation for hypervisors.

Vulnerability Information

BINARLY internal vulnerability identifier: BRLY-2025-018
Lenovo PSIRT assigned CVE identifier: CVE-2025-4426
Lenovo advisory: LEN-201013
Insyde advisory: INSYDE-SA-2025007
CVSS v3.1: 6.0 Medium AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N

Table of Contents

01.Affected firmware

02.Vulnerability description

03.Disclosure timeline

04.Acknowledgements

Affected firmware

Device name	Unpacked firmware SHA256	Firmware version	OEM	IBV	Module name	Module GUID	Module SHA256	Module kind
ideacentre-aio-3-24arr9	39214500da92c1f37fabc733127c3ac46ea0302eb5ad97a18e562fc3f17111e1	O6KKT12A (2025-01-16)	Lenovo	Insyde	SetupAutomationSmm	dc08d13d-ec1a-4458-b37a-c50118d7ac48	87cafb102629124735c2e506956606875378e8c4d7b32ed8abc95e79fafd4657	SmmModule
ideacentre-aio-3-24irh9	54f3ed6c1c43ccd228c7965c483e8a476d271b7b850fe39a628343443da4229f	O6AKT1DA/1.0.0.29 (2024-08-09)	Lenovo	Insyde	SetupAutomationSmm	dc08d13d-ec1a-4458-b37a-c50118d7ac48	890616a5a64cb65044a9420a3b674d9e2a1bfa9e5aae1082e48ce6e8c9fa6348	SmmModule
yoga-aio-9-32irh8	6e1c212345471b08ca6aa41b1f1996e924191d6b88d5190c51bf82452f194858	O62KT24A (2024-08-08)	Lenovo	Insyde	SetupAutomationSmm	dc08d13d-ec1a-4458-b37a-c50118d7ac48	e31fb0dfec46d7e0dcef3de2488859da00c7e2439d2f91eb0938f94bd5052199	SmmModule

Vulnerability description

Let's consider the module 87cafb102629124735c2e506956606875378e8c4d7b32ed8abc95e79fafd4657.

This module contains custom logic to register SMI handlers (callbacks) using EFI_L05_SMM_SW_SMI_INTERFACE_PROTOCOL:

EFI_STATUS RegisterCallbackFunctions()
{
  UINTN Offset;
  EFI_STATUS Status;
  EFI_L05_SMM_SW_SMI_INTERFACE_PROTOCOL *EfiL05SmmSwSmiInterfaceProtocol;

  Offset = 0;
  EfiL05SmmSwSmiInterfaceProtocol = 0;
  Status0 = gSmst->SmmLocateProtocol(&EFI_SMM_CPU_PROTOCOL_GUID, 0, &gEfiSmmCpuProtocol);
  if ( EFI_SUCCESS(Status) )
  {
    Status0 = gSmst->SmmLocateProtocol(&EFI_SMM_VARIABLE_PROTOCOL_GUID, 0, &gEfiSmmVariableProtocol);
    if ( EFI_SUCCESS(Status) )
    {
      Status0 = gSmst->SmmLocateProtocol(
                  &EFI_L05_SMM_SW_SMI_INTERFACE_PROTOCOL_GUID,
                  0,
                  &EfiL05SmmSwSmiInterfaceProtocol);
      if ( EFI_SUCCESS(Status) )
      {
        do
        {
          Status = EfiL05SmmSwSmiInterfaceProtocol->RegisterCallbackFunction(
                     EfiL05SmmSwSmiInterfaceProtocol,
                     0x20,
                     FeatureCallbackType,
                     *(&gCallbacksTable.Function + Offset));
          if ( Status == EFI_OUT_OF_RESOURCES )
            break;
          Offset += 16;
        }
        while ( Offset < 0x30 );
        CalculateCrc32Table();
        return Status;
      }
    }
  }
  return Status0;
}

After executing this function, all handlers from gCallbacksTable will be registered in the following loop (with SwSmiNum = 0x20):

do
{
  Status = EfiL05SmmSwSmiInterfaceProtocol->RegisterCallbackFunction(
              EfiL05SmmSwSmiInterfaceProtocol,
              0x20,
              FeatureCallbackType,
              *(&gCallbacksTable.Function + Offset));
  if ( Status == EFI_OUT_OF_RESOURCES )
    break;
  Offset += 16;
}
while ( Offset < 0x30 );

gCallbacksTable contains 3 SMI handlers:

.data:00000000000030C0 ; CALLBACK_ITEM gCallbacksTable
.data:00000000000030C0 gCallbacksTable CALLBACK_ITEM <4, offset Callback04>
.data:00000000000030C0                                         ; DATA XREF: RegisterCallbackFunctions+83↑o
.data:00000000000030D0                 CALLBACK_ITEM <0Fh, offset Callback0F>
.data:00000000000030E0                 CALLBACK_ITEM <0B8h, offset CallbackB8>

The pseudocode of Callback04 function is shown below:

MACRO_EFI Callback04(UINTN CpuIndex)
{
  PARAM_BUFFER *Param;
  UINTN Index;
  PARAM_BUFFER_VARIABLE *Var;
  CHAR16 *Name;
  UINT32 NameSize;
  UINT8 *VariableData;
  UINT32 RdiReg;
  UINT32 RsiReg;
  CHAR16 VariableName[128];
  UINT32 RaxReg;
  UINT32 RbxReg;
  UINT32 RcxReg;

  RaxReg = 0;
  RbxReg = 0;
  RcxReg = 0;
  RdiReg = 0;
  RsiReg = 0;
  gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RAX, CpuIndex, &RaxReg);
  gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RBX, CpuIndex, &RbxReg);
  gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RCX, CpuIndex, &RcxReg);
  gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RDI, CpuIndex, &RdiReg);
  gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RSI, CpuIndex, &RsiReg);
  if ( RaxReg != 0x534D0420 )
    return EFI_UNSUPPORTED;
  if ( RbxReg != 0x1323190D || RcxReg != 0xD121F1E )
  {
    RaxReg = 0x80000000;
    gEfiSmmCpuProtocol->WriteSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RAX, CpuIndex, &RaxReg);
    return EFI_UNSUPPORTED;
  }
  Param = RdiReg;
  Index = 0;

  // Attacker-controlled pointer
  Var = (RdiReg + 0x38);

if ( Param->Count )
  {
    do
    {
      ZeroMem(VariableName, 200);
      Name = &Var->VariableName;
      NameSize = Var->VariableNameSize;
      if ( NameSize )
      {
        if ( VariableName != Name )
        {
          // 1. VariableNameSize is not validated -> overflow of VariableName stack buffer
          CopyMem(VariableName, Name, Var->VariableNameSize);
          NameSize = Var->VariableNameSize;
        }
      }
      VariableData = &Var->VariableName + NameSize;
      // 2. SmmSetVariable() is used with attacker-controlled arguments
      // 3. VariableData can point in SMRAM -> SMRAM disclosure
      gEfiSmmVariableProtocol->SmmSetVariable(
        VariableName,
        &Var->VariableGuid,
        VARIABLE_ATTRIBUTE_NV_BS_RT,
        Var->VariableDataSize,
        VariableData);
      ++Index;
      Var = &VariableData[Var->VariableDataSize];
    }
    while ( Index < Param->Count );
  }
  RaxReg = 0;
  gEfiSmmCpuProtocol->WriteSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RAX, CpuIndex, &RaxReg);
  return 0;
}

The RdiReg value (obtained from the RDI register using gEfiSmmCpuProtocol->ReadSaveState) is controlled by the attacker.

The buffer pointed to by Var = (RdiReg + 0x38) has the following structure:

00000000 struct PARAM_BUFFER_VARIABLE
00000000 {
00000000     UINT32 VariableAttributes;
00000004     UINT32 VariableNameSize;
00000008     UINT32 VariableDataSize;
0000000C     EFI_GUID VariableGuid;
0000001C     UINT32 VariableName;
00000020 };

The function performs the following operation to set NVRAM variable with controllable parameters:

VariableData = &Var->VariableName + NameSize;
// 2. SmmSetVariable() is used with attacker-controlled arguments
// 3. VariableData can point in SMRAM -> SMRAM disclosure
gEfiSmmVariableProtocol->SmmSetVariable(
  VariableName,
  &Var->VariableGuid,
  VARIABLE_ATTRIBUTE_NV_BS_RT,
  Var->VariableDataSize,
  VariableData);
++Index;

The VariableData pointer is controlled by the attacker and can point to SMRAM or just before SMRAM, allowing an attacker to write SMRAM contents (up to 64 KiB) to an NVRAM variable with a chosen name and GUID.

Disclosure timeline

This vulnerability is subject to a 90 day disclosure period. After 90 days or when a patch has been made generally available (whichever comes first) the advisory will be publicly disclosed.

Disclosure Activity	Date
Lenovo PSIRT is notified	2025-04-08
Lenovo PSIRT is confirmed issue	2025-06-16
Lenovo PSIRT assigned CVE number	2025-06-16
BINARLY public disclosure date	2025-07-29

Acknowledgements

BINARLY REsearch team

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Potential Impact

Device name

Unpacked firmware SHA256

Firmware version

OEM

IBV

Module name

Module GUID

Module SHA256

Module kind

ideacentre-aio-3-24arr9

39214500da92c1f37fabc733127c3ac46ea0302eb5ad97a18e562fc3f17111e1

O6KKT12A (2025-01-16)

Lenovo

Insyde

SetupAutomationSmm

dc08d13d-ec1a-4458-b37a-c50118d7ac48

87cafb102629124735c2e506956606875378e8c4d7b32ed8abc95e79fafd4657

SmmModule

ideacentre-aio-3-24irh9

54f3ed6c1c43ccd228c7965c483e8a476d271b7b850fe39a628343443da4229f

O6AKT1DA/1.0.0.29 (2024-08-09)

Lenovo

Insyde

SetupAutomationSmm

dc08d13d-ec1a-4458-b37a-c50118d7ac48

890616a5a64cb65044a9420a3b674d9e2a1bfa9e5aae1082e48ce6e8c9fa6348

SmmModule

yoga-aio-9-32irh8

6e1c212345471b08ca6aa41b1f1996e924191d6b88d5190c51bf82452f194858

O62KT24A (2024-08-08)

Lenovo

Insyde

SetupAutomationSmm

dc08d13d-ec1a-4458-b37a-c50118d7ac48

e31fb0dfec46d7e0dcef3de2488859da00c7e2439d2f91eb0938f94bd5052199

SmmModule

EFI_STATUS RegisterCallbackFunctions() { UINTN Offset; EFI_STATUS Status; EFI_L05_SMM_SW_SMI_INTERFACE_PROTOCOL *EfiL05SmmSwSmiInterfaceProtocol; Offset = 0; EfiL05SmmSwSmiInterfaceProtocol = 0; Status0 = gSmst->SmmLocateProtocol(&EFI_SMM_CPU_PROTOCOL_GUID, 0, &gEfiSmmCpuProtocol); if ( EFI_SUCCESS(Status) ) { Status0 = gSmst->SmmLocateProtocol(&EFI_SMM_VARIABLE_PROTOCOL_GUID, 0, &gEfiSmmVariableProtocol); if ( EFI_SUCCESS(Status) ) { Status0 = gSmst->SmmLocateProtocol( &EFI_L05_SMM_SW_SMI_INTERFACE_PROTOCOL_GUID, 0, &EfiL05SmmSwSmiInterfaceProtocol); if ( EFI_SUCCESS(Status) ) { do { Status = EfiL05SmmSwSmiInterfaceProtocol->RegisterCallbackFunction( EfiL05SmmSwSmiInterfaceProtocol, 0x20, FeatureCallbackType, *(&gCallbacksTable.Function + Offset)); if ( Status == EFI_OUT_OF_RESOURCES ) break; Offset += 16; } while ( Offset < 0x30 ); CalculateCrc32Table(); return Status; } } } return Status0; }

do { Status = EfiL05SmmSwSmiInterfaceProtocol->RegisterCallbackFunction( EfiL05SmmSwSmiInterfaceProtocol, 0x20, FeatureCallbackType, *(&gCallbacksTable.Function + Offset)); if ( Status == EFI_OUT_OF_RESOURCES ) break; Offset += 16; } while ( Offset < 0x30 );

.data:00000000000030C0 ; CALLBACK_ITEM gCallbacksTable .data:00000000000030C0 gCallbacksTable CALLBACK_ITEM <4, offset Callback04> .data:00000000000030C0 ; DATA XREF: RegisterCallbackFunctions+83↑o .data:00000000000030D0 CALLBACK_ITEM <0Fh, offset Callback0F> .data:00000000000030E0 CALLBACK_ITEM <0B8h, offset CallbackB8>

MACRO_EFI Callback04(UINTN CpuIndex) { PARAM_BUFFER *Param; UINTN Index; PARAM_BUFFER_VARIABLE *Var; CHAR16 *Name; UINT32 NameSize; UINT8 *VariableData; UINT32 RdiReg; UINT32 RsiReg; CHAR16 VariableName[128]; UINT32 RaxReg; UINT32 RbxReg; UINT32 RcxReg; RaxReg = 0; RbxReg = 0; RcxReg = 0; RdiReg = 0; RsiReg = 0; gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RAX, CpuIndex, &RaxReg); gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RBX, CpuIndex, &RbxReg); gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RCX, CpuIndex, &RcxReg); gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RDI, CpuIndex, &RdiReg); gEfiSmmCpuProtocol->ReadSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RSI, CpuIndex, &RsiReg); if ( RaxReg != 0x534D0420 ) return EFI_UNSUPPORTED; if ( RbxReg != 0x1323190D || RcxReg != 0xD121F1E ) { RaxReg = 0x80000000; gEfiSmmCpuProtocol->WriteSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RAX, CpuIndex, &RaxReg); return EFI_UNSUPPORTED; } Param = RdiReg; Index = 0; // Attacker-controlled pointer Var = (RdiReg + 0x38); if ( Param->Count ) { do { ZeroMem(VariableName, 200); Name = &Var->VariableName; NameSize = Var->VariableNameSize; if ( NameSize ) { if ( VariableName != Name ) { // 1. VariableNameSize is not validated -> overflow of VariableName stack buffer CopyMem(VariableName, Name, Var->VariableNameSize); NameSize = Var->VariableNameSize; } } VariableData = &Var->VariableName + NameSize; // 2. SmmSetVariable() is used with attacker-controlled arguments // 3. VariableData can point in SMRAM -> SMRAM disclosure gEfiSmmVariableProtocol->SmmSetVariable( VariableName, &Var->VariableGuid, VARIABLE_ATTRIBUTE_NV_BS_RT, Var->VariableDataSize, VariableData); ++Index; Var = &VariableData[Var->VariableDataSize]; } while ( Index < Param->Count ); } RaxReg = 0; gEfiSmmCpuProtocol->WriteSaveState(gEfiSmmCpuProtocol, 4, EFI_SMM_SAVE_STATE_REGISTER_RAX, CpuIndex, &RaxReg); return 0; }

00000000 struct PARAM_BUFFER_VARIABLE 00000000 { 00000000 UINT32 VariableAttributes; 00000004 UINT32 VariableNameSize; 00000008 UINT32 VariableDataSize; 0000000C EFI_GUID VariableGuid; 0000001C UINT32 VariableName; 00000020 };

VariableData = &Var->VariableName + NameSize; // 2. SmmSetVariable() is used with attacker-controlled arguments // 3. VariableData can point in SMRAM -> SMRAM disclosure gEfiSmmVariableProtocol->SmmSetVariable( VariableName, &Var->VariableGuid, VARIABLE_ATTRIBUTE_NV_BS_RT, Var->VariableDataSize, VariableData); ++Index;

Disclosure Activity

Date

Lenovo PSIRT is notified

2025-04-08

Lenovo PSIRT is confirmed issue

2025-06-16

Lenovo PSIRT assigned CVE number

2025-06-16

BINARLY public disclosure date

2025-07-29

Potential Impact

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Vulnerability Information

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Affected firmware

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Vulnerability description

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Disclosure timeline

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Acknowledgements

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See if you are impacted now with our Firmware Vulnerability Scanner

Potential Impact

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Vulnerability Information

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Affected firmware

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Vulnerability description

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Disclosure timeline

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Acknowledgements

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See if you are impacted now with our Firmware Vulnerability Scanner