CVE-2024-37326: Microsoft SQL Server 2016 RCE Vulnerability

CVE-2024-37326 Overview

CVE-2024-37326 is a remote code execution vulnerability in the Microsoft SQL Server Native Client OLE DB Provider. The flaw affects SQL Server 2016, 2017, 2019, and 2022. Microsoft published the advisory on July 9, 2024 as part of its monthly security update cycle.

The vulnerability is associated with [CWE-122: Heap-based Buffer Overflow]. Successful exploitation requires user interaction, typically by tricking a client into connecting to an attacker-controlled SQL Server. Compromise results in arbitrary code execution in the context of the connecting application.

Critical Impact
An attacker who convinces an authenticated user to connect a vulnerable client to a malicious SQL Server instance can execute arbitrary code with the privileges of the connecting process.

Affected Products

Microsoft SQL Server 2016
Microsoft SQL Server 2017
Microsoft SQL Server 2019
Microsoft SQL Server 2022

Discovery Timeline

2024-07-09 - Microsoft releases security patch and discloses CVE-2024-37326
2024-07-09 - CVE-2024-37326 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-37326

Vulnerability Analysis

The vulnerability resides in the SQL Server Native Client (SNAC) OLE DB Provider, a low-level interface used by applications to communicate with SQL Server using the Tabular Data Stream (TDS) protocol. The provider mishandles data returned from a SQL Server during the connection or query response phase, leading to a heap-based buffer overflow.

Exploitation follows a client-side attack pattern. The attacker hosts a malicious SQL Server endpoint and lures a user into initiating a connection from an application that uses the vulnerable OLE DB provider. The malicious server returns crafted TDS packets that corrupt heap memory in the client process.

The attack vector is network-based and does not require prior authentication on the attacker's malicious endpoint. Successful exploitation grants code execution in the security context of the client process, allowing the attacker to take actions consistent with that user's privileges.

Root Cause

The root cause is improper validation of length or size fields in server-supplied data parsed by the OLE DB provider, leading to memory corruption on the heap [CWE-122]. Insufficient bounds checking allows attacker-controlled data to overwrite adjacent heap structures, which can be steered toward control-flow hijacking.

Attack Vector

The attack vector is remote and requires user interaction. A victim must initiate or be coerced into initiating an outbound connection from a vulnerable client to a malicious SQL Server. Common scenarios include phishing emails containing connection strings, malicious Office documents that trigger ODBC/OLE DB connections, or compromised internal tooling that points at attacker-controlled hosts.

No verified public exploit code is available for CVE-2024-37326. Refer to the Microsoft Security Update Guide for vendor-confirmed technical details.

Detection Methods for CVE-2024-37326

Indicators of Compromise

Outbound TDS connections (typically TCP/1433 or dynamic ports) from workstations or application servers to untrusted external IP addresses.
Unexpected child processes spawned by applications that consume the SQL Server Native Client OLE DB Provider (msoledbsql.dll, sqlncli11.dll).
Crashes or heap corruption events in processes hosting OLE DB providers, visible in Windows Error Reporting and WER dumps.
Newly created scheduled tasks, services, or persistence artifacts following SQL client connectivity to unfamiliar hosts.

Detection Strategies

Hunt for processes loading msoledbsql.dll or sqlncli*.dll that subsequently spawn shells (cmd.exe, powershell.exe) or LOLBins.
Correlate TDS handshake traffic to non-corporate destinations with endpoint process telemetry to identify lured client connections.
Inspect WER and application crash logs for access violations originating in msoledbsql.dll or related SQL client libraries.

Monitoring Recommendations

Inventory all hosts with SQL Server Native Client or msoledbsql.dll installed and track patch status against Microsoft's July 2024 update.
Enforce egress filtering so that workstations cannot reach arbitrary external SQL Server endpoints on TDS ports.
Enable detailed process and module-load logging (Sysmon Event IDs 1, 7, 11) on systems running database tooling and ETL agents.

How to Mitigate CVE-2024-37326

Immediate Actions Required

Apply the cumulative updates listed in the Microsoft Security Update Guide for CVE-2024-37326 to all affected SQL Server 2016, 2017, 2019, and 2022 installations.
Update the standalone msoledbsql.dll OLE DB Driver for SQL Server on all client systems, including application servers, BI workstations, and developer endpoints.
Restrict outbound TCP/1433 and other TDS traffic from end-user networks to only sanctioned database servers.

Patch Information

Microsoft addressed CVE-2024-37326 in the July 9, 2024 Patch Tuesday release. Cumulative updates are available for SQL Server 2016 SP3, 2017, 2019, and 2022. The fix also applies to the redistributable Microsoft OLE DB Driver for SQL Server. Patch metadata and binary versions are documented in the vendor advisory.

Workarounds

Where patching is delayed, block outbound TDS connections from clients to untrusted networks at the firewall and proxy layer.
Train users to avoid opening connection strings, .udl files, or database links from untrusted sources.
Remove or disable the SQL Server Native Client / OLE DB Provider on systems that do not require database connectivity.

bash

# Example: block outbound TDS to non-approved destinations on Windows hosts
New-NetFirewallRule -DisplayName "Block-Outbound-TDS" `
  -Direction Outbound -Protocol TCP -RemotePort 1433 `
  -Action Block -RemoteAddress Internet