CVE-2024-26214 Overview
CVE-2024-26214 is a remote code execution vulnerability in the Microsoft WDAC Open Database Connectivity (ODBC) Driver for SQL Server. The flaw affects every supported Windows client and Windows Server release, from Windows 10 1507 through Windows 11 23H2 and from Windows Server 2008 through Windows Server 2022 23H2. Microsoft assigned the issue a CVSS 3.1 base score of 8.8 and mapped it to CWE-122: Heap-based Buffer Overflow. Successful exploitation lets an attacker run arbitrary code in the context of the application that loads the driver, after a user is convinced to connect to an attacker-controlled SQL Server instance.
Critical Impact
An attacker who tricks a user into initiating an ODBC connection to a malicious SQL Server can achieve remote code execution with full confidentiality, integrity, and availability impact.
Affected Products
- Microsoft Windows 10 (1507, 1607, 1809, 21H2, 22H2) and Windows 11 (21H2, 22H2, 23H2)
- Microsoft Windows Server 2008 SP2, 2008 R2 SP1, 2012, and 2012 R2
- Microsoft Windows Server 2016, 2019, 2022, and 2022 23H2
Discovery Timeline
- 2024-04-09 - CVE-2024-26214 published to NVD as part of Microsoft's April 2024 Patch Tuesday
- 2024-12-06 - Last updated in NVD database
Technical Details for CVE-2024-26214
Vulnerability Analysis
The vulnerability resides in the Windows Data Access Components (WDAC) ODBC driver used to connect Windows applications to Microsoft SQL Server. The driver mishandles data received from a remote SQL Server, leading to memory corruption on the heap as classified by CWE-122. An attacker who controls the server-side responses can craft payloads that overflow heap buffers inside the client process. The result is arbitrary code execution in the security context of the user or service that initiated the connection. Because ODBC is widely embedded in business applications, reporting tools, and scripts, the attack surface extends well beyond standalone database clients.
Root Cause
Microsoft has classified the root cause as a heap-based buffer overflow in the WDAC SQL Server ODBC driver. The driver does not correctly validate the size of data returned from a SQL Server before copying it into a fixed-size heap allocation. When the server response exceeds the expected bounds, adjacent heap metadata and objects are overwritten. An attacker who shapes the heap and the overwrite payload can pivot the corruption into control of execution flow.
Attack Vector
The attack vector is network-based but requires user interaction. A target user must initiate or be coerced into initiating an ODBC connection to a SQL Server instance under the attacker's control. Common delivery scenarios include phishing emails containing Office documents, .odc files, or shortcuts that trigger an outbound connection. Once the client connects, the attacker returns crafted protocol responses that exploit the heap overflow. No prior authentication on the client is required, and the attacker only needs to host or impersonate a SQL Server endpoint reachable from the victim.
No public proof-of-concept exploit code is currently available for CVE-2024-26214. Refer to the Microsoft Security Update Guide entry for CVE-2024-26214 for vendor-supplied technical detail.
Detection Methods for CVE-2024-26214
Indicators of Compromise
- Outbound TCP connections to untrusted SQL Server endpoints, typically on port 1433 or dynamically negotiated ports via the SQL Browser service on UDP 1434.
- Unexpected child processes spawned by applications that load sqlsrv32.dll or other WDAC ODBC components.
- Crash dumps or Windows Error Reporting events referencing access violations inside the WDAC ODBC driver.
Detection Strategies
- Hunt for processes loading the WDAC SQL Server ODBC driver that subsequently initiate suspicious child processes such as cmd.exe, powershell.exe, or rundll32.exe.
- Correlate email or web-delivered files with .odc, .udl, or .iqy extensions to user-initiated SQL Server connections that immediately precede process anomalies.
- Inspect EDR telemetry for behavioral indicators of heap corruption, including in-process exception handler abuse and unexpected memory region allocations marked executable.
Monitoring Recommendations
- Log and review all outbound SQL Server traffic leaving end-user subnets, where legitimate volume should be low.
- Enable Windows Defender Exploit Guard and Attack Surface Reduction rules that block Office applications from creating child processes.
- Forward client-side application crash telemetry referencing ODBC modules to your SIEM for correlation with phishing and web proxy events.
How to Mitigate CVE-2024-26214
Immediate Actions Required
- Apply the April 2024 Microsoft security updates that address CVE-2024-26214 on all affected Windows client and server builds.
- Inventory hosts that have the WDAC SQL Server ODBC driver installed and prioritize patching workstations used by analysts, developers, and database administrators.
- Restrict outbound TCP 1433 and UDP 1434 traffic at the perimeter so internal clients cannot reach arbitrary external SQL Server endpoints.
- Reinforce phishing awareness for users likely to receive database connection files or links.
Patch Information
Microsoft released fixes through the April 2024 Patch Tuesday cycle. Administrators should consult the Microsoft Security Update Guide for CVE-2024-26214 for the specific KB articles applicable to each Windows version. The cumulative updates supersede prior monthly rollups and must be deployed across both client and server SKUs, including legacy Server 2008 and 2012 systems covered by Extended Security Updates.
Workarounds
- Block egress to untrusted SQL Server endpoints using host and perimeter firewalls until patches are deployed.
- Disable or remove unused ODBC data sources and uninstall the WDAC SQL Server ODBC driver on systems where it is not required.
- Apply Attack Surface Reduction rules to prevent Office applications from launching ODBC connections through embedded content.
# Example: block outbound SQL Server traffic from end-user workstations
New-NetFirewallRule -DisplayName "Block Outbound MSSQL 1433" `
-Direction Outbound -Protocol TCP -RemotePort 1433 -Action Block
New-NetFirewallRule -DisplayName "Block Outbound SQL Browser 1434" `
-Direction Outbound -Protocol UDP -RemotePort 1434 -Action Block
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
