CVE-2024-37327: Microsoft SQL Server 2016 RCE Vulnerability

CVE-2024-37327 Overview

CVE-2024-37327 is a remote code execution vulnerability in the Microsoft SQL Server Native Client OLE DB Provider. The flaw resides in the Object Linking and Embedding Database (OLE DB) provider component used by SQL Server to handle client connections and data access operations. An attacker can exploit this issue by convincing an authenticated user to connect to a malicious SQL Server instance, which then returns crafted responses that trigger memory corruption on the client. Successful exploitation grants the attacker code execution in the context of the connecting user. The vulnerability affects SQL Server 2016, 2017, 2019, and 2022. Microsoft classifies the underlying weakness as a heap-based buffer overflow [CWE-122].

Critical Impact
Remote attackers can achieve arbitrary code execution on systems running vulnerable Microsoft SQL Server versions when a user connects to an attacker-controlled SQL Server instance.

Affected Products

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

Discovery Timeline

2024-07-09 - CVE-2024-37327 published to NVD
2024-07-09 - Microsoft releases security update via MSRC advisory
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-37327

Vulnerability Analysis

The vulnerability exists in the SQL Server Native Client OLE DB Provider, the component responsible for negotiating connections and parsing Tabular Data Stream (TDS) responses between clients and SQL Server. The flaw is classified as a heap-based buffer overflow [CWE-122]. When the client processes specially crafted response data from a SQL Server, it writes beyond the bounds of a heap-allocated buffer. This corruption can be leveraged to overwrite adjacent heap structures and redirect program execution. Exploitation requires user interaction, meaning a victim must initiate or be tricked into initiating a connection to an attacker-controlled SQL Server endpoint. With an EPSS score of 1.611% (72.9th percentile), the vulnerability has moderate predicted exploitation likelihood relative to other published CVEs.

Root Cause

The root cause is improper bounds validation when the OLE DB Provider parses server-supplied data structures. The provider trusts size or length fields supplied by the remote server when allocating or copying response payloads into heap buffers. A malformed or oversized field allows the provider to write data past the allocated region, corrupting heap metadata and adjacent allocations.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker hosts a malicious SQL Server instance that responds to client connections with crafted TDS or OLE DB protocol messages. The attacker then uses phishing, social engineering, or supply chain tactics to induce a victim to connect using an application that relies on the SQL Server Native Client OLE DB Provider. Common targets include database administration tools, custom line-of-business applications, and any process that opens an OLE DB connection string referencing an external server. Code executes with the privileges of the user running the vulnerable client process.

No verified public proof-of-concept code is available for this vulnerability. Refer to the Microsoft CVE-2024-37327 Advisory for additional technical context.

Detection Methods for CVE-2024-37327

Indicators of Compromise

Outbound TCP connections from workstations or application servers to untrusted SQL Server endpoints (default port 1433 or custom ports) outside the organization's known database inventory.
Unexpected child processes spawned by applications hosting OLE DB providers such as sqlservr.exe, sqlncli11.dll, or msoledbsql.dll.
Crash dumps or Windows Error Reporting events referencing heap corruption inside the SQL Server Native Client or MSOLEDBSQL modules.

Detection Strategies

Monitor process telemetry for OLE DB consumer processes loading sqlncli11.dll or msoledbsql.dll followed by anomalous memory allocations, shellcode-like behavior, or token manipulation.
Inspect network flows for SQL Server connections established to public IP ranges or recently registered domains, which are uncommon in legitimate enterprise traffic.
Correlate user-driven connection events from spreadsheet and reporting tools with subsequent unexpected command-line activity such as cmd.exe, powershell.exe, or rundll32.exe spawning from the parent application.

Monitoring Recommendations

Audit installed versions of SQL Server Native Client and MSOLEDBSQL across endpoints and servers and flag versions predating the July 2024 Microsoft security update.
Enable Windows Defender Exploit Guard or equivalent memory protections and forward heap corruption telemetry to a centralized log platform for correlation.
Apply egress filtering rules to restrict outbound connections on SQL Server ports to a known allowlist of internal database hosts.

How to Mitigate CVE-2024-37327

Immediate Actions Required

Apply the Microsoft security updates referenced in the Microsoft CVE-2024-37327 Advisory to all instances of SQL Server 2016, 2017, 2019, and 2022, including standalone clients that ship the Native Client OLE DB Provider.
Inventory all systems with sqlncli11.dll or msoledbsql.dll installed, including application servers, developer workstations, and reporting hosts, and prioritize patching for internet-facing or user-facing systems.
Educate users with database access to avoid opening connection strings, ODC files, or query files received from untrusted sources.

Patch Information

Microsoft published fixed builds for all supported SQL Server branches alongside the July 2024 security update cycle. Patch metadata and download links are available through the Microsoft CVE-2024-37327 Advisory. Administrators should validate that both the database engine and any redistributable Native Client and MSOLEDBSQL packages installed on client systems are updated, since the vulnerable code path lives in the client-side provider library.

Workarounds

Restrict outbound traffic on SQL Server ports (1433 and any custom-configured ports) to an internal allowlist using host or network firewalls.
Remove the legacy SQL Server Native Client (sqlncli11.dll) from systems where it is no longer required, and migrate applications to a patched Microsoft OLE DB Driver release.
Enforce application allowlisting to prevent untrusted processes from invoking OLE DB consumers with attacker-supplied connection strings.

bash

# Inventory SQL Server Native Client and MSOLEDBSQL versions on Windows hosts
Get-WmiObject -Class Win32_Product | \
  Where-Object { $_.Name -match 'SQL Server.*Native Client' -or $_.Name -match 'OLE DB Driver' } | \
  Select-Object Name, Version, Vendor