CVE-2024-49079: Windows 10 1507 IME RCE Vulnerability

CVE-2024-49079 Overview

CVE-2024-49079 is a Remote Code Execution vulnerability in the Windows Input Method Editor (IME) component. This vulnerability stems from a Use-After-Free (CWE-416) memory corruption issue that could allow an attacker to execute arbitrary code on the target system. The attack requires local access and user interaction, such as opening a specially crafted file or visiting a malicious website that triggers the vulnerable IME component.

Critical Impact

Successful exploitation allows an attacker to execute arbitrary code with the privileges of the current user, potentially leading to complete system compromise including access to sensitive data, installation of malware, or lateral movement within the network.

Affected Products

• Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (versions 22H2, 23H2, 24H2)
• Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2, and 2025

Discovery Timeline

• December 12, 2024 - CVE-2024-49079 published to NVD
• January 8, 2025 - Last updated in NVD database

Technical Details for CVE-2024-49079

Vulnerability Analysis

This vulnerability affects the Input Method Editor (IME) component, which is a fundamental Windows feature that enables users to input characters and symbols not typically available on a standard keyboard. IME is particularly essential for entering East Asian languages such as Chinese, Japanese, and Korean characters. The flaw involves a Use-After-Free condition where the IME component references memory that has been previously freed, creating an opportunity for code execution.

When a user processes specially crafted input through the IME, the vulnerability can be triggered, causing the system to access freed memory. An attacker who successfully exploits this vulnerability could run arbitrary code in the context of the current user. If the current user has administrative privileges, the attacker would gain full system control.

Root Cause

The vulnerability originates from a Use-After-Free (CWE-416) memory management flaw in the Windows IME component. This occurs when the software continues to reference a memory location after it has been freed, and an attacker can manipulate the contents of that memory to redirect program execution. Improper handling of object lifecycles within the IME processing routines leads to this dangerous condition.

Attack Vector

The attack requires local access to the target system, and user interaction is necessary to trigger the vulnerability. An attacker could deliver a malicious payload through several methods:

The vulnerability requires the attacker to convince a user to open a specially crafted file or interact with malicious content that triggers the IME component. This could be achieved through phishing emails containing weaponized documents, malicious websites designed to exploit the IME during text input operations, or compromised applications that process user input through the vulnerable IME routines.

Once the user interacts with the malicious content, the Use-After-Free condition is triggered, and the attacker's code executes with the privileges of the logged-in user.

Detection Methods for CVE-2024-49079

Indicators of Compromise

• Unexpected crashes or errors in IME-related processes such as ctfmon.exe or IME host processes
• Suspicious memory access patterns or exception events in Windows Event Logs related to text input services
• Unusual child processes spawned from IME components or text services framework processes
• Anomalous behavior following document or webpage interaction involving non-standard character input

Detection Strategies

• Deploy endpoint detection and response (EDR) solutions to monitor for suspicious process behavior associated with IME components
• Enable Windows Defender Exploit Guard with Attack Surface Reduction (ASR) rules to detect and block potentially malicious IME activity
• Monitor for unexpected code execution patterns originating from text input framework processes
• Implement application whitelisting to prevent unauthorized code execution in the context of IME operations

Monitoring Recommendations

• Enable detailed logging for Windows Text Services Framework and IME-related events
• Configure SIEM rules to alert on unusual process spawning from ctfmon.exe or related IME processes
• Monitor for memory corruption indicators such as heap spray patterns or suspicious memory allocations
• Establish baseline behavior for IME processes and alert on deviations

How to Mitigate CVE-2024-49079

Immediate Actions Required

• Apply Microsoft security updates from the December 2024 Patch Tuesday release immediately
• Prioritize patching workstations and servers where users regularly interact with IME functionality
• Implement network segmentation to limit lateral movement potential if exploitation occurs
• Educate users about the risks of opening untrusted files or visiting suspicious websites

Patch Information

Microsoft has released security updates to address this vulnerability as part of their December 2024 security release cycle. Organizations should obtain and apply the appropriate patches from the Microsoft Security Update Guide. The patches are available for all supported Windows versions listed in the affected products section.

Administrators should use Windows Server Update Services (WSUS), Microsoft Configuration Manager, or Windows Update for Business to deploy patches across enterprise environments efficiently.

Workarounds

• Restrict user interaction with untrusted documents and websites until patches can be applied
• Consider temporarily disabling non-essential IME features in high-risk environments where alternate input methods are not required
• Implement strict application control policies to prevent unauthorized code execution
• Use Protected View in Microsoft Office applications to provide an additional layer of protection when opening documents from untrusted sources

# Verify patch installation status for CVE-2024-49079
# Check installed updates via PowerShell
Get-HotFix | Where-Object {$_.InstalledOn -ge (Get-Date "2024-12-10")} | Format-Table -AutoSize

# Query Windows Update history for recent security updates
Get-WmiObject -Class Win32_QuickFixEngineering | Sort-Object InstalledOn -Descending | Select-Object -First 10