Rule Category

FILE-OFFICE -- Snort detected traffic targeting vulnerabilities in files belonging to the Microsoft Office suite of software (Excel, PowerPoint, Word, Visio, Access, Outlook, etc.).

Alert Message

FILE-OFFICE Microsoft MSHTML ActiveX control bypass attempt

Rule Explanation

This rule looks for malicious crafted DOCX and RTF files, that specifically have the ability to launch a download from any site of the attacker's choice.

What To Look For

This rule will fire when malicious crafted DOCX and RTF files designed to exploit CVE-2021-40444 are detected on the network.

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Initial Access

Technique: Trusted Relationship

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

Additional Links

Rule Vulnerability

Remote File Inclusion

Remote File Inclusion (RFI) attacks occur when a webserver takes a file crafted by an attacker as input and runs or stores it in an unsafe manner. For instance, the webserver could accept an image file that is actually code, then call it to execute after uploading. RFI attacks happen on web applications that dynamically include external files or scripts. A successful RFI can lead to data leaks, remote code execution, or cross site scripting. Avoid dynamic inclusion of user input files, or whitelist files that may be included. Keep the PHP allow_url_include option set to off; this will not protect against Local File Inclusion attacks.

CVE Additional Information