Microsoft SharePoint Server Remote Code Execution (RCE) Vulnerability (CVE-2023-24955) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTMicrosoft SharePoint Server 2016, 2019, and Subscription Edition
An authenticated attacker with high privileges (Site Owner/Administrator) can execute arbitrary code in the context of the server, leading to complete system compromise
Apply the official Microsoft security patches immediately and restrict access to the SharePoint administration interface from untrusted networks
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Refer to the Microsoft Security Update Guide to download and install the appropriate Cumulative Update (CU) for your SharePoint version. Use the following PowerShell commands to verify your current SharePoint farm build version and patch status.
# Verify SharePoint Farm Build Version
Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
Get-SPFarm | Select-Object BuildVersion
# Check for missing required patches
Get-SPProduct | Where-Object { $_.RequiredButMissingPatches } | Format-Table -Property DisplayName, MissingPatches2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, restrict access to the SharePoint Central Administration and web applications to trusted IP ranges using IIS IP Security restrictions. Run the following PowerShell commands to enforce IP restrictions.
# Enable IIS IP Security Feature
Install-WindowsFeature Web-IP-Security
# Restrict access to SharePoint Central Administration to a specific subnet
Import-Module WebAdministration
Set-WebConfigurationProperty -Filter '/system.webServer/security/ipSecurity' -Name 'allowUnlisted' -Value $false -PSPath 'IIS:\' -Location 'SharePoint Central Administration v4'
Add-WebConfigurationProperty -Filter '/system.webServer/security/ipSecurity' -Name '.' -Value @{ipAddress='10.0.0.0';subnetMask='255.255.0.0';allowed='true'} -PSPath 'IIS:\' -Location 'SharePoint Central Administration v4'3. Log Audit & IoC Verification Commands
Analyze SharePoint Unified Logging Service (ULS) logs and IIS W3C logs for anomalous POST requests or serialization exceptions. Use the following script to search for potential exploitation indicators in ULS logs.
# Merge and search ULS logs for serialization and compilation exceptions
Merge-SPLogFile -Path 'C:\Logs\Analyzed_ULS.log' -Overwrite
Select-String -Path 'C:\Logs\Analyzed_ULS.log' -Pattern 'System.Runtime.Serialization', 'Assembly.Load', 'VirtualPathProvider' | Select-Object -First 100Block Exploits Instantly with Managed Virtual Patching Rules
Can't patch production immediately? Deploy managed WAF rules at the edge to intercept RCE, SQLi, and deserialization payloads before they hit your origin server.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2023-24955) is a critical Remote Code Execution (RCE) flaw in Microsoft SharePoint Server. The root cause lies in the server's unsafe handling of user-supplied input during deserialization or dynamic code compilation processes (CWE-94). When an authenticated attacker with administrative privileges sends a specially crafted payload, the SharePoint backend fails to properly validate the input, allowing the execution of arbitrary .NET code within the server's security context.
2. Exploitation Mechanics & Attack Scenario
In a typical exploitation scenario, an attacker first gains administrative access to the SharePoint site, often by chaining this flaw with an authentication bypass vulnerability (such as CVE-2023-29357) or using compromised credentials. Once authenticated, the attacker leverages administrative endpoints or Web Part configurations to upload malicious .NET assemblies or serialized payloads. The SharePoint server processes this data, triggering unsafe deserialization or compilation, which executes the attacker's payload and establishes a web shell or executes system commands.
3. Infrastructure & Business Impact
As this vulnerability is actively exploited in the wild and listed in the CISA KEV catalog, it poses an immediate threat to enterprise environments. Successful exploitation grants the attacker the privileges of the SharePoint service account, which often possesses extensive domain or local system rights. This can lead to unauthorized access to sensitive corporate documents, lateral movement within the Active Directory domain, and deployment of ransomware.
Official Vendor Advisories & References
Microsoft SharePoint Server Remote Code Execution Vulnerability
Frequently Asked SecOps Questions (CVE-2023-24955)
FAQQ1. How critical is CVE-2023-24955 and is it actively exploited in the wild?
CVE-2023-24955 is rated CVSS 7.2 (HIGH) with a 30-day EPSS exploitation probability of 85.0%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2023-24955?
Primary impacted vendors include microsoft across sharepoint_server. Scope summary: Microsoft SharePoint Server 2016, 2019, and SharePoint Server Subscription Edition (unpatched versions)
Q3. What temporary mitigations or workarounds exist for CVE-2023-24955 before patching?
[Mitigation] Apply the official Microsoft security patches immediately and restrict access to the SharePoint administration interface from untrusted networks Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2023-24955
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
🔗 Related Advisories in Similar Stack (microsoft)
View Category →Microsoft SharePoint Remote Code Execution (RCE) Vulnerability Advisory (CVE-2026-65660)
[Affected Scope] Microsoft SharePoint Server 2016, 2019, and Subscription Edition.
Microsoft SharePoint Server Remote Code Execution (RCE) Vulnerability Advisory (CVE-2026-58644, CWE-502)
[Affected Scope] Microsoft SharePoint Server deployments
Microsoft Office SharePoint Missing Authentication Privilege Escalation Vulnerability (CVE-2026-56164) Security Advisory
[Affected Scope] Microsoft Office SharePoint Server environments
Microsoft SharePoint Remote Code Execution (RCE) Vulnerability Advisory (CVE-2026-50522, CWE-502)
[Affected Scope] Microsoft SharePoint Server deployments
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