CVE-2024-26244 Overview
CVE-2024-26244 is a remote code execution vulnerability in the Microsoft Windows Data Access Components (WDAC) Object Linking and Embedding Database (OLE DB) provider for SQL Server. The flaw stems from an integer underflow condition [CWE-191] within the provider's handling of data received from a SQL Server. An attacker who controls a malicious SQL Server can trigger memory corruption when a victim client connects to it, leading to code execution in the context of the connecting application. The vulnerability affects supported releases of Windows 10, Windows 11, and Windows Server from 2008 through 2022 23H2.
Critical Impact
Successful exploitation allows attackers to execute arbitrary code on a victim system after coercing a user to connect to an attacker-controlled SQL Server, with high impact to confidentiality, integrity, and availability.
Affected Products
- Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 21H2, 22H2, 23H2)
- Microsoft Windows Server 2008, 2012, 2016, 2019, 2022, and Server 2022 23H2
Discovery Timeline
- 2024-04-09 - CVE-2024-26244 published to NVD as part of Microsoft's April 2024 Patch Tuesday
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-26244
Vulnerability Analysis
The vulnerability resides in the WDAC OLE DB provider for SQL Server, a Windows component used by applications to communicate with SQL Server instances. Microsoft classifies the underlying weakness as an integer underflow [CWE-191]. When the provider parses certain response data from a SQL Server, an arithmetic operation can wrap below zero. This produces an undersized buffer calculation that subsequently allows out-of-bounds memory access during data processing.
The vulnerability requires user interaction. A user must be tricked into connecting to a malicious SQL Server, typically through social engineering or a poisoned connection string in a document or application. Once the connection is established, the malicious server returns crafted packets that exploit the underflow. Code executes with the privileges of the application performing the SQL connection.
Root Cause
The root cause is unsafe arithmetic on size fields within the OLE DB provider's response-parsing logic. When the parser computes buffer offsets or lengths from server-supplied values without proper bounds checks, attacker-controlled values can wrap the integer space and produce a value that bypasses subsequent length validation.
Attack Vector
The attack is network-based but requires the victim to initiate or accept a connection to the attacker's SQL Server. Common scenarios include phishing emails carrying Office documents with embedded data connections, applications configured with attacker-controlled DSNs, or man-in-the-middle interception of an existing SQL Server connection. No prior authentication on the victim system is required.
No public proof-of-concept exploit code has been released. Technical details are documented in the Microsoft Security Update for CVE-2024-26244.
Detection Methods for CVE-2024-26244
Indicators of Compromise
- Unexpected outbound TCP connections from user workstations or application servers to SQL Server port 1433 (or custom SQL ports) on untrusted external hosts.
- Crash dumps or Windows Error Reporting events naming msdaora.dll, sqloledb.dll, msoledbsql.dll, or other OLE DB provider modules.
- Spawning of cmd.exe, powershell.exe, or other LOLBins as child processes of applications that load OLE DB providers, such as excel.exe, winword.exe, or custom line-of-business tools.
Detection Strategies
- Hunt for process trees where Office applications or database client tools initiate connections to external IPs on SQL Server ports, then spawn script interpreters or download utilities.
- Monitor module load events for OLE DB provider DLLs in processes that do not normally interact with SQL Server.
- Correlate Sysmon Event ID 3 (network connection) with Event ID 1 (process create) to identify post-connection code execution patterns originating from OLE DB consumers.
Monitoring Recommendations
- Inventory applications using ADO, OLE DB, or ODBC to connect to SQL Server, and baseline their normal destination hosts.
- Enable command-line and module load auditing on endpoints and forward to a centralized SIEM for correlation.
- Alert on connections to SQL Server endpoints outside corporate IP ranges or cloud database CIDRs.
How to Mitigate CVE-2024-26244
Immediate Actions Required
- Apply the April 2024 Microsoft security update for all affected Windows client and server editions listed in the advisory.
- Block outbound TCP 1433 and other SQL Server ports at the perimeter except to sanctioned database hosts.
- Audit application configurations and Office documents for hardcoded or user-modifiable SQL Server connection strings.
Patch Information
Microsoft released fixes on April 9, 2024 as part of monthly cumulative updates. Patch identifiers and download links for each affected Windows and Windows Server SKU are listed in the Microsoft Security Update Guide for CVE-2024-26244. Apply the cumulative update that corresponds to the installed Windows version.
Workarounds
- Restrict end-user ability to initiate ad-hoc SQL Server connections from Office applications by disabling external data connections via Group Policy.
- Use TLS-protected SQL connections with strict server certificate validation to prevent attacker-controlled servers from impersonating legitimate database hosts.
- Apply application allowlisting to block unsigned or unexpected child processes spawned from OLE DB consumer applications.
# Verify the April 2024 cumulative update is installed (PowerShell)
Get-HotFix | Where-Object { $_.InstalledOn -ge (Get-Date '2024-04-09') } |
Sort-Object InstalledOn -Descending |
Format-Table HotFixID, Description, InstalledOn
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
