CVE-2024-49043: Microsoft SQL Server 2016 RCE Vulnerability

CVE-2024-49043 Overview

CVE-2024-49043 is a remote code execution vulnerability affecting the Microsoft.SqlServer.XEvent.Configuration.dll component in Microsoft SQL Server. This vulnerability allows attackers to execute arbitrary code on affected systems through the exploitation of an untrusted search path weakness (CWE-426). The vulnerability requires local access and user interaction to exploit, but successful exploitation could result in complete system compromise with high impact to confidentiality, integrity, and availability.

Critical Impact

Successful exploitation enables attackers to execute arbitrary code with the privileges of the SQL Server process, potentially leading to full system compromise, data exfiltration, and lateral movement within enterprise environments.

Affected Products

• Microsoft SQL Server 2016 (x64)
• Microsoft SQL Server 2017 (x64)
• Microsoft SQL Server 2019 (x64)
• Microsoft SQL Server 2022 (x64)

Discovery Timeline

• November 12, 2024 - CVE-2024-49043 published to NVD
• November 15, 2024 - Last updated in NVD database

Technical Details for CVE-2024-49043

Vulnerability Analysis

This vulnerability resides in the Microsoft.SqlServer.XEvent.Configuration.dll library, which is responsible for handling Extended Events configuration within SQL Server. Extended Events is SQL Server's lightweight performance monitoring system used by database administrators for diagnostics and troubleshooting.

The vulnerability is classified under CWE-426 (Untrusted Search Path), indicating that the affected DLL component improperly handles the search path when loading external libraries or resources. When exploited, an attacker can manipulate the search path to load malicious code instead of legitimate system components.

The attack requires local access to the system and user interaction, suggesting a scenario where an attacker either has existing access to the machine or can convince a user to execute a malicious action that triggers the vulnerability.

Root Cause

The root cause stems from an untrusted search path vulnerability in the Microsoft.SqlServer.XEvent.Configuration.dll component. When the SQL Server process attempts to load dependent libraries or resources, it may search directories in an order that allows attacker-controlled paths to take precedence over secure system locations. This enables DLL hijacking or similar path manipulation attacks where a malicious library can be loaded instead of the legitimate one.

Attack Vector

The attack vector is local, requiring the attacker to have access to the target system. The exploitation scenario typically involves:

1. An attacker places a malicious DLL in a location that appears earlier in the search path than the legitimate library
2. A user or process triggers functionality in SQL Server that causes the vulnerable component to load external dependencies
3. The malicious DLL is loaded instead of the legitimate one, executing arbitrary code with the privileges of the SQL Server process

Since user interaction is required, this vulnerability may be exploited through social engineering tactics that convince an administrator to perform actions that trigger the vulnerable code path.

Detection Methods for CVE-2024-49043

Indicators of Compromise

• Unexpected DLL files appearing in SQL Server installation directories or system PATH locations
• Unusual process execution originating from SQL Server service accounts
• Anomalous file writes or modifications in SQL Server Extended Events configuration paths
• Suspicious loaded modules in SQL Server processes that do not match expected Microsoft signatures

Detection Strategies

• Monitor SQL Server processes for loading of unsigned or untrusted DLLs using application whitelisting solutions
• Implement file integrity monitoring on SQL Server installation directories and system PATH locations
• Enable Windows Event logging for process creation events (Event ID 4688) with command line auditing to detect suspicious activity
• Deploy endpoint detection solutions to identify DLL hijacking attempts and unauthorized code execution

Monitoring Recommendations

• Configure SentinelOne to alert on DLL loading anomalies within SQL Server processes
• Establish baseline behavior for Extended Events configuration activity and alert on deviations
• Monitor for unauthorized modifications to system PATH environment variables
• Review SQL Server error logs for unusual component loading failures or security exceptions

How to Mitigate CVE-2024-49043

Immediate Actions Required

• Apply the latest security updates from Microsoft for all affected SQL Server versions immediately
• Review and restrict file system permissions on SQL Server installation directories and system PATH locations
• Audit systems for unexpected DLL files in sensitive directories
• Implement application whitelisting to prevent unauthorized code execution

Patch Information

Microsoft has released security updates to address this vulnerability. Administrators should apply the appropriate patches for their SQL Server version as detailed in the Microsoft Security Update Guide. The patches address the untrusted search path issue by implementing stricter path validation and loading controls in the affected component.

Workarounds

• Restrict write access to directories in the system PATH to administrators only
• Enable Windows Defender Application Control (WDAC) or similar application control policies
• Run SQL Server services with least-privilege accounts to limit the impact of potential exploitation
• Implement strict directory ACLs on SQL Server installation folders to prevent unauthorized file placement

# Verify SQL Server version and check for required patches
# Run in SQL Server Management Studio or sqlcmd
SELECT @@VERSION;

# Review loaded modules for SQL Server process
# PowerShell command to audit loaded DLLs
Get-Process -Name sqlservr | ForEach-Object { $_.Modules } | Select-Object FileName, FileVersion | Export-Csv -Path "sqlserver_modules.csv"