CVE-2024-21373 Overview
CVE-2024-21373 is a remote code execution vulnerability in the Microsoft SQL Server Native Client OLE DB Provider. The flaw affects supported SQL Server releases from 2016 through 2022 on x64 platforms. An attacker can trigger arbitrary code execution by convincing a user to connect to a malicious SQL server or open a crafted resource that invokes the vulnerable provider. The vulnerability is classified under [CWE-122] (Heap-based Buffer Overflow). Microsoft assigned a CVSS 3.1 base score of 8.8, and the EPSS probability is 1.688% (73.98 percentile).
Critical Impact
Successful exploitation grants remote code execution with the privileges of the application loading the OLE DB Provider, enabling full compromise of the SQL client host.
Affected Products
- Microsoft SQL Server 2016 (x64)
- Microsoft SQL Server 2017 (x64)
- Microsoft SQL Server 2019 (x64)
- Microsoft SQL Server 2022 (x64)
Discovery Timeline
- 2024-07-09 - CVE-2024-21373 published to NVD
- 2025-01-15 - Last updated in NVD database
Technical Details for CVE-2024-21373
Vulnerability Analysis
The vulnerability resides in the SQL Server Native Client OLE DB Provider, a component used by client applications to connect to SQL Server instances. The provider mishandles data returned from a server during the connection or query response handling path. This mishandling produces a heap-based buffer overflow, which corrupts adjacent heap structures and allows attacker-controlled data to influence execution flow. The component is reachable over the network when client software initiates a connection to an attacker-controlled endpoint. Because the provider runs in-process with the calling application, code execution occurs in the security context of that application.
Root Cause
The root cause is improper validation of memory boundaries when the OLE DB Provider parses server-supplied protocol data, leading to a heap-based buffer overflow tracked under [CWE-122]. Insufficient size checks on incoming structured fields allow data to be written past the bounds of an allocated heap buffer. Attackers can craft response payloads that overwrite control structures or function pointers on the heap.
Attack Vector
Exploitation requires user interaction. An attacker hosts a malicious SQL endpoint and lures a victim into initiating a connection from an application that uses the SQL Server Native Client OLE DB Provider. The malicious server responds with a crafted byte sequence that triggers the heap overflow during response parsing. No prior authentication to the victim host is required, and the attack traverses the network. Refer to the Microsoft CVE-2024-21373 Advisory for vendor-specific exploitation conditions.
No public proof-of-concept or in-the-wild exploitation has been confirmed for this CVE. See the vendor advisory for protocol-level technical detail.
Detection Methods for CVE-2024-21373
Indicators of Compromise
- Outbound TDS (Tabular Data Stream) connections from workstations or application servers to unexpected external IP addresses or ports.
- Crashes or unexpected restarts of processes that load sqlncli.dll, msoledbsql.dll, or related OLE DB Provider libraries.
- Child processes spawned by Office applications, BI tools, or custom data clients shortly after a database connection attempt.
Detection Strategies
- Inventory hosts that load the SQL Server Native Client OLE DB Provider and monitor those processes for anomalous memory access violations.
- Hunt for endpoint telemetry showing OLE DB-consuming applications making outbound connections to non-corporate SQL endpoints.
- Correlate Windows Error Reporting events referencing heap corruption in OLE DB modules against recent SQL connection events.
Monitoring Recommendations
- Log and alert on TCP/1433 and dynamically assigned SQL Browser traffic egressing the corporate perimeter.
- Enable command-line and module-load auditing on systems running line-of-business applications that consume OLE DB.
- Track installed versions of MSOLEDBSQL and SQL Server Native Client across the estate to identify unpatched clients.
How to Mitigate CVE-2024-21373
Immediate Actions Required
- Apply the Microsoft security update referenced in the Microsoft CVE-2024-21373 Advisory to all SQL Server 2016, 2017, 2019, and 2022 installations.
- Update client-side OLE DB Provider components (msoledbsql.dll) on any workstation or server that connects to SQL Server.
- Restrict outbound database connections to known internal SQL Server endpoints using firewall egress rules.
Patch Information
Microsoft has released security updates addressing the heap-based buffer overflow in the SQL Server Native Client OLE DB Provider. Patches are distributed through Microsoft Update and the SQL Server cumulative update channel. Refer to the Microsoft CVE-2024-21373 Advisory for the specific KB articles and build numbers mapped to each affected version.
Workarounds
- Block outbound TCP/1433 and SQL Browser UDP/1434 traffic at the perimeter for hosts that do not require external database connectivity.
- Restrict execution of OLE DB-consuming applications to trusted users, reducing the impact of user-interaction-based exploitation.
- Educate users to avoid opening untrusted database connection files, ODC files, or links that initiate SQL connections to external servers.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
