Rule Category

SERVER-WEBAPP -- Snort has detected traffic exploiting vulnerabilities in web based applications on servers.

Alert Message

SERVER-WEBAPP Microsoft SharePoint attachment upload deserialization attempt

Rule Explanation

This rule looks for an upload which may be used to trigger a deserialization vulnerability.

What To Look For

This rule fires upon attempted upload of a malicious attachment to a Microsoft SharePoint server, which may be used to exploit CVE-2021-27076.

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Execution

Technique: Execution through API

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org

Additional Links

Rule Vulnerability

Insecure Deserialization

Insecure Deserialization relates to web application security. Applications turn an object into data through serialization; the reverse of that process, deserialization, can be vulnerable to attacks when the application trusts the data that is being deserialized. Serialized data is machine readable and not encrypted; serialized user-supplied data should not be trusted. Deserialization attacks can lead to remote code execution.

CVE Additional Information