CVE-2024-38024: Microsoft SharePoint Server RCE Vulnerability

CVE-2024-38024 Overview

CVE-2024-38024 is a remote code execution vulnerability in Microsoft SharePoint Server rooted in insecure deserialization of untrusted data [CWE-502]. An authenticated attacker with elevated site permissions can send crafted requests to a vulnerable SharePoint server and execute arbitrary code in the context of the SharePoint process. Microsoft addressed the flaw in the July 2024 security update cycle. The vulnerability affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Server 2016.

Critical Impact
Successful exploitation grants attackers code execution on the SharePoint server, exposing document repositories, service credentials, and lateral movement paths across the enterprise collaboration platform.

Affected Products

Microsoft SharePoint Server Subscription Edition
Microsoft SharePoint Server 2019
Microsoft SharePoint Server 2016

Discovery Timeline

2024-07-09 - CVE-2024-38024 published to NVD with Microsoft security update guidance
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-38024

Vulnerability Analysis

CVE-2024-38024 is an Insecure Deserialization vulnerability [CWE-502] in Microsoft SharePoint Server. SharePoint processes serialized objects submitted through authenticated request paths without adequately validating the object types before reconstruction. An attacker who submits a crafted serialized payload can trigger arbitrary type instantiation and gadget chain execution during deserialization. This results in code execution inside the SharePoint worker process, typically running under a service account with broad access to farm content and configuration databases. The high EPSS percentile associated with this CVE reflects strong exploitation interest across the security community, even though no public exploit or CISA KEV listing is currently attributed to it.

Root Cause

The root cause is unsafe handling of user-controlled serialized data inside SharePoint request processing. The affected code path reconstructs .NET objects from attacker-influenced streams without a strict type allowlist. Deserialization then invokes constructors and setters on gadget types available in the SharePoint assemblies, yielding controlled code execution.

Attack Vector

Exploitation requires network access to the SharePoint web front-end and an authenticated account with high privileges on the target site. The attacker submits a crafted request containing a malicious serialized payload to a vulnerable SharePoint endpoint. The server deserializes the payload during normal request handling, executing attacker-supplied logic in the SharePoint application pool identity. No user interaction is required beyond the attacker's own authenticated session.

No verified public proof-of-concept code is available for CVE-2024-38024. Refer to the Microsoft Security Update Guide entry for CVE-2024-38024 for authoritative technical detail.

Detection Methods for CVE-2024-38024

Indicators of Compromise

Unusual child processes spawned by w3wp.exe hosting the SharePoint application pool, particularly cmd.exe, powershell.exe, or script hosts.
Unexpected outbound network connections originating from SharePoint web front-end servers to untrusted hosts.
New or modified .aspx, .ashx, or web shell artifacts under SharePoint web application directories such as C:\inetpub\wwwroot\wss\VirtualDirectories\.
IIS request logs containing large or base64-encoded POST bodies to SharePoint endpoints from a single authenticated principal.

Detection Strategies

Hunt for process ancestry where the SharePoint IIS worker process launches interactive shells, LOLBins, or reconnaissance utilities such as whoami, net.exe, or nltest.
Correlate SharePoint ULS logs with Windows Security event logs to identify privileged accounts submitting anomalous serialized payloads.
Inspect HTTP request bodies for serialized .NET markers such as TypeObject, __type, or System.Windows.Data.ObjectDataProvider gadget references.

Monitoring Recommendations

Forward IIS, SharePoint ULS, and Windows event telemetry to a central analytics platform and retain for a minimum of 90 days.
Alert on any credential dumping or LSASS access attempts originating from SharePoint servers.
Baseline normal administrative activity on SharePoint farms and flag deviations by privileged accounts.

How to Mitigate CVE-2024-38024

Immediate Actions Required

Apply the July 2024 Microsoft security update for SharePoint Server on all farm servers, including web front-end, application, and search roles.
Audit accounts with elevated SharePoint site permissions and revoke unnecessary Site Owner or Farm Administrator rights.
Rotate credentials for SharePoint service accounts if compromise is suspected on any farm server.
Restrict SharePoint administrative endpoints to trusted networks and require multi-factor authentication for privileged users.

Patch Information

Microsoft has released security updates for all supported SharePoint Server versions. Consult the Microsoft Security Update Guide entry for CVE-2024-38024 for the specific KB articles applicable to SharePoint Server Subscription Edition, 2019, and 2016. Patches must be installed on every server in the farm followed by the SharePoint Products Configuration Wizard.

Workarounds

No official Microsoft workaround eliminates the vulnerability; patching is the required remediation.
Limit high-privilege SharePoint permissions to reduce the population of accounts able to reach the vulnerable code path.
Place SharePoint front-ends behind a web application firewall configured to inspect and block serialized .NET payloads.
Segment SharePoint servers from broader corporate networks to contain post-exploitation lateral movement.

bash

# Verify SharePoint patch level after installation
Get-SPFarm | Select-Object BuildVersion
Get-HotFix | Where-Object { $_.InstalledOn -ge (Get-Date).AddDays(-60) } | Sort-Object InstalledOn -Descending