Overview
The vulnerability in focus, CVE-2025-54897, is a critical flaw that lies in the deserialization of untrusted data in Microsoft Office SharePoint. This vulnerability could be exploited by an authorized attacker to execute arbitrary code over a network. Given the widespread use of Microsoft Office SharePoint in business environments across the globe, this vulnerability has the potential to affect a vast number of systems, posing a serious cybersecurity threat. Its exploitation could lead to system compromise and potential data leakage, thus emphasizing the importance of adequately addressing this vulnerability.
Vulnerability Summary
CVE ID: CVE-2025-54897
Severity: High (8.8 CVSS)
Attack Vector: Network
Privileges Required: Low
User Interaction: None
Impact: System compromise or potential data leakage
Affected Products
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Product | Affected Versions
Microsoft Office SharePoint | All versions prior to the security update
How the Exploit Works
The exploit takes advantage of the insecure deserialization process within Microsoft Office SharePoint. Insecure deserialization often leads to remote code execution if an attacker can modify the serialized (or flattened) object that the application then deserializes. In this case, an attacker who has access to the SharePoint server can send serialized, untrusted data to it. The server, failing to properly validate or sanitize the data, deserializes it and potentially executes malicious code embedded within the untrusted data.
Conceptual Example Code
The following is a conceptual example of a crafted malicious payload sent to the SharePoint server:
POST /SharePoint/endpoint HTTP/1.1
Host: target.example.com
Content-Type: application/json
{
"serialized_object": "rO0ABXNyABdqYXZhLnV0aWwuSGFzaFNldLpEhZ5+3c4vAwAGSgAFY2FwYWNpdHl4cgAPamF2YS51dGlsLkFic3RyYWN0U2V0iO0cMlknAwABeHAAAAAAdwQAAAAEAAAAeHg="
}In this example, the “serialized_object” is an encoded representation of a malicious object. When the SharePoint server deserializes the object, it could potentially run the malicious code contained within it.
It’s crucial to remember that the above example is a simplified representation of how the vulnerability might be exploited. Real-world exploitation would likely involve more complex payloads and additional steps.
Recommended Mitigation
The primary mitigation for this vulnerability is to apply the security patch provided by the vendor, Microsoft in this case. If for some reason the patch cannot be applied immediately, it is recommended to use Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDSs) as temporary mitigation measures. These solutions can be configured to detect and block the specific types of requests that could exploit this vulnerability. However, these are only temporary measures and applying the vendor patch should be prioritized to ensure full protection against this vulnerability.
