CVE-2024-49010: Microsoft SQL Server 2016 RCE Vulnerability

CVE-2024-49010 Overview

CVE-2024-49010 is a remote code execution vulnerability affecting Microsoft SQL Server Native Client. The flaw is rooted in a heap-based buffer overflow [CWE-122] within the client component used by applications to connect to SQL Server. An attacker who convinces a user to connect to a malicious SQL Server instance can trigger memory corruption and execute arbitrary code in the context of the targeted process. The vulnerability impacts SQL Server 2016, 2017, and 2019 on x64 platforms. Microsoft published the advisory on November 12, 2024.

Critical Impact

Successful exploitation grants attackers remote code execution on systems running affected SQL Server Native Client versions, with full confidentiality, integrity, and availability impact when a user is tricked into initiating a connection to an attacker-controlled server.

Affected Products

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

Discovery Timeline

• 2024-11-12 - CVE-2024-49010 published to NVD
• 2024-11-12 - Microsoft releases security update addressing the vulnerability
• 2024-11-15 - Last updated in NVD database

Technical Details for CVE-2024-49010

Vulnerability Analysis

The vulnerability resides in the SQL Server Native Client, the data access component (sqlncli) used by client applications to communicate with SQL Server using the Tabular Data Stream (TDS) protocol. The flaw is classified as a heap-based buffer overflow [CWE-122], meaning the client writes beyond the bounds of a heap-allocated buffer when processing server-supplied data.

Exploitation requires user interaction. An attacker must convince an authenticated or unauthenticated user to initiate a connection from a vulnerable client to a malicious SQL Server endpoint controlled by the attacker. Once connected, the rogue server sends crafted TDS responses that overflow internal buffers in the client.

Because the attack vector is network-based and requires no prior privileges on the target, the EPSS model rates this issue in a higher exploitation probability tier than most Microsoft RCEs from the same release.

Root Cause

The root cause is improper validation of length or size fields in data returned by the SQL Server during a client-server exchange. When the Native Client copies the malformed payload into a fixed-size heap buffer, the write exceeds the allocation, corrupting adjacent heap structures. Attackers leverage this corruption to overwrite function pointers or vtable entries and redirect execution.

Attack Vector

The attack vector is a malicious or compromised SQL Server instance. Typical scenarios include phishing links that launch a database client with attacker-supplied connection strings, malicious ODBC data source files (.dsn or .udl), or compromised internal SQL endpoints that respond to legitimate clients with crafted TDS packets. The vulnerable code path executes in the address space of the host application that loaded the Native Client library, so impact scales with the privileges of the calling process.

No public proof-of-concept code is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog at the time of writing. See the Microsoft CVE-2024-49010 Advisory for vendor technical details.

Detection Methods for CVE-2024-49010

Indicators of Compromise

• Unexpected outbound connections from workstations or application servers to untrusted hosts on TCP port 1433 or dynamic SQL Server ports.
• Crashes or anomalous termination of processes loading sqlncli11.dll or sqlncli10.dll, particularly with heap corruption exception codes such as 0xC0000374.
• Connection strings referencing external IP addresses or unfamiliar hostnames sourced from email attachments, .udl files, or office documents.

Detection Strategies

• Inventory all systems with the SQL Server Native Client installed and correlate against patch status from the November 2024 Microsoft security update.
• Monitor child processes spawned by applications that load sqlncli*.dll for unexpected shell, scripting, or LOLBin activity following an outbound database connection.
• Hunt for Windows Error Reporting (WER) entries and Application event log faults referencing the Native Client modules.

Monitoring Recommendations

• Enable egress filtering and log all SQL Server protocol traffic leaving the corporate network to detect connections to attacker-controlled endpoints.
• Track creation of ODBC data sources, .udl files, and connection strings in user profile directories.
• Alert on EDR telemetry showing heap corruption exceptions in processes that subsequently spawn cmd.exe, powershell.exe, or rundll32.exe.

How to Mitigate CVE-2024-49010

Immediate Actions Required

• Apply the Microsoft security update for SQL Server 2016, 2017, and 2019 published in the November 2024 release cycle.
• Identify and inventory all hosts with the SQL Server Native Client (sqlncli) installed, including application servers, developer workstations, and reporting endpoints.
• Restrict outbound TCP connections to SQL Server ports so that internal clients cannot reach untrusted external database hosts.
• Educate users about the risk of opening connection files (.udl, .dsn, .odc) received via email or downloaded from the web.

Patch Information

Microsoft has released cumulative updates that address CVE-2024-49010 for the SQL Server Native Client components shipped with SQL Server 2016, 2017, and 2019. Patch details, KB numbers, and download links are available in the Microsoft CVE-2024-49010 Advisory. Administrators should validate that both the database engine and any stand-alone Native Client redistributable installations are updated.

Workarounds

• Where patching cannot be applied immediately, block outbound connections from end-user workstations to TCP port 1433 and known SQL Server dynamic port ranges at the perimeter firewall.
• Migrate applications from the deprecated SQL Server Native Client to the supported Microsoft OLE DB Driver for SQL Server (MSOLEDBSQL) or Microsoft ODBC Driver for SQL Server, which are not affected by this issue.
• Disable or remove the Native Client redistributable on hosts where it is not required by line-of-business applications.

# Configuration example: enumerate hosts with SQL Server Native Client installed
# Run from an elevated PowerShell session against a target list
Get-Content .\hosts.txt | ForEach-Object {
    Invoke-Command -ComputerName $_ -ScriptBlock {
        Get-WmiObject -Class Win32_Product |
            Where-Object { $_.Name -like '*SQL Server*Native Client*' } |
            Select-Object PSComputerName, Name, Version
    }
} | Export-Csv -Path .\sqlncli-inventory.csv -NoTypeInformation