CVE-2020-1457: Microsoft Windows 10 Codecs Library RCE Flaw

CVE-2020-1457 Overview

A remote code execution vulnerability exists in the way that Microsoft Windows Codecs Library handles objects in memory. This vulnerability, tracked as CVE-2020-1457, allows attackers to execute arbitrary code on vulnerable systems when a user opens a specially crafted image file. The flaw is related to improper memory handling during image processing operations, specifically classified as an out-of-bounds write vulnerability (CWE-787).

This CVE ID is unique from CVE-2020-1425, another related vulnerability in the Windows Codecs Library that was disclosed around the same time.

Critical Impact

Successful exploitation allows attackers to execute arbitrary code with the privileges of the current user, potentially leading to complete system compromise when users view malicious image files.

Affected Products

• Microsoft Windows 10 Version 1709
• Microsoft Windows 10 Version 1803
• Microsoft Windows 10 Version 1809
• Microsoft Windows 10 Version 1903
• Microsoft Windows 10 Version 1909
• Microsoft Windows 10 Version 2004

Discovery Timeline

• July 27, 2020 - CVE-2020-1457 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-1457

Vulnerability Analysis

This vulnerability is an out-of-bounds write (CWE-787) in the Microsoft Windows Codecs Library. The flaw occurs when the library improperly handles objects in memory during image file processing. When a user opens a specially crafted image file, the codec library fails to properly validate memory boundaries, allowing data to be written outside the intended buffer region.

The vulnerability requires local access and user interaction to exploit—specifically, a victim must open a malicious image file. Once triggered, the out-of-bounds write can corrupt adjacent memory structures, potentially allowing an attacker to hijack program execution flow and run arbitrary code with the privileges of the current user.

Root Cause

The root cause lies in insufficient boundary checking within the Windows Codecs Library during memory operations when processing image data. The library fails to properly validate the size and content of image objects before writing them to memory buffers, resulting in an out-of-bounds write condition. This memory corruption vulnerability can be leveraged to overwrite critical data structures and gain code execution.

Attack Vector

The attack vector is local, requiring user interaction to succeed. An attacker would need to convince a user to open a maliciously crafted image file, which could be delivered through various means:

• Email attachments with embedded or linked malicious images
• Web pages hosting specially crafted image content
• Compromised file shares or removable media
• Social engineering to encourage downloading and viewing malicious files

When the victim opens the crafted image file, the Windows Codecs Library processes it, triggering the out-of-bounds write and potentially executing the attacker's payload. The vulnerability does not require elevated privileges to exploit, though the attacker gains code execution with the privileges of the user who opened the file.

Detection Methods for CVE-2020-1457

Indicators of Compromise

• Unexpected crashes or errors in applications using the Windows Codecs Library
• Suspicious image files with malformed or unusual header structures
• Process anomalies where image viewing applications spawn unexpected child processes
• Memory access violations logged in Windows Event Viewer

Detection Strategies

• Monitor for abnormal behavior in processes that handle image rendering, such as unexpected code execution or privilege escalation attempts
• Implement endpoint detection rules to identify exploitation attempts targeting media codec components
• Use application whitelisting to detect unauthorized code execution from image processing workflows
• Deploy SentinelOne Singularity to detect memory corruption exploitation techniques in real-time

Monitoring Recommendations

• Enable Windows Defender Exploit Guard to detect memory corruption attempts
• Configure logging for Windows Error Reporting to capture application crashes related to codec processing
• Monitor network traffic for suspicious image file downloads from untrusted sources
• Implement file integrity monitoring on system codec libraries

How to Mitigate CVE-2020-1457

Immediate Actions Required

• Apply the security update from Microsoft immediately for all affected Windows 10 versions
• Restrict user access to untrusted image files until patches are deployed
• Enable attack surface reduction rules in Windows Defender to limit exploitation vectors
• Educate users about the risks of opening image files from untrusted sources

Patch Information

Microsoft has released security updates to address this vulnerability. The patch corrects how the Windows Codecs Library handles objects in memory. Organizations should apply the update available through the Microsoft Security Advisory CVE-2020-1457. The Windows Codecs Library is updated automatically through the Microsoft Store for affected Windows 10 versions.

Additional technical details about the vulnerability are available in the Zero Day Initiative Advisory ZDI-20-1081.

Workarounds

• Disable automatic image preview in file browsers and email clients until patches are applied
• Block or quarantine suspicious image files at email and web gateways
• Use application sandboxing for programs that process untrusted image content
• Consider restricting execution of untrusted content using Windows Sandbox or virtualization

# Verify Windows Codecs Library update status via PowerShell
Get-AppxPackage -Name "Microsoft.HEVCVideoExtension*" | Select Name, Version
Get-AppxPackage -Name "Microsoft.VP9VideoExtensions*" | Select Name, Version

# Force update of Microsoft Store apps including codec components
wsreset.exe