Trojan:VBA/FV represents a family of malicious macro-based threats that embed themselves in Microsoft Office documents, primarily Word and Excel files. These trojans exploit Visual Basic for Applications (VBA) code to execute unauthorized commands when users enable macros in infected documents. Once activated, the trojan typically downloads and installs additional malware payloads, establishes persistence mechanisms, and can grant attackers remote access to the compromised system.
This threat family has been circulating since at least 2015, with numerous variants appearing in phishing campaigns targeting both home users and business environments. The "FV" designation indicates a specific detection pattern within the broader VBA trojan category, though individual samples vary significantly in their exact payload and behavior.
Threat Profile
| Attribute | Details |
|---|---|
| Threat Family | Trojan:VBA (Macro-based document trojan) |
| Platform | Windows (via Microsoft Office documents) |
| Targeted Applications | Microsoft Word, Excel, PowerPoint (all versions supporting VBA macros) |
| Primary Distribution | Phishing emails with malicious attachments, compromised document repositories |
| Initial Execution Trigger | User enabling macros in infected document |
| Common Payloads | Banking trojans, ransomware downloaders, information stealers, backdoor installers |
| Persistence Mechanisms | Registry Run keys, scheduled tasks, Office add-ins, template injection |
| Network Behavior | HTTPS connections to command-and-control servers, secondary payload downloads (often disguised as legitimate traffic) |
| Typical Indicators | Unexpected macro prompts, unsigned VBA code, AutoOpen/AutoExec procedures, PowerShell or wscript.exe child processes from Office applications |
| Detection Rate | Variable (obfuscation techniques frequently updated to evade signature-based detection) |
| Removal Difficulty | Moderate to High (depends on secondary payload deployment) |
| Data at Risk | Banking credentials, stored passwords, personal documents, system access credentials |
How It Spreads
Trojan:VBA/FV spreads almost exclusively through social engineering tactics that convince users to open infected Office documents and enable macros. The most common distribution method involves phishing emails crafted to appear legitimate — invoices from vendors, shipping notifications, tax documents, or business proposals. These emails often create urgency ("Your account will be suspended unless you review this document immediately") or appeal to curiosity ("Performance review — confidential") to bypass the recipient's natural skepticism.
The infected documents themselves typically display a fake error message or deliberately garbled content when first opened, instructing the user that they must "Enable Content" or "Enable Editing" to view the document properly. This is a deliberate deception — the document appears broken specifically to trick users into enabling the macros that will activate the trojan. Once macros are enabled, the malicious VBA code executes silently in the background while displaying convincing decoy content to the user.
Secondary distribution methods include:
- Compromised cloud storage links: Attackers share infected documents through legitimate services like Dropbox, Google Drive, or OneDrive, lending false credibility to the file
- Malicious advertisements: Drive-by downloads that deliver infected documents when users click on fake "Download" buttons or software update prompts
- Infected document templates: Trojanized templates uploaded to document-sharing sites that appear when users search for resume templates, invoice formats, or business forms
- Lateral movement within networks: Once one machine is infected, the trojan may propagate through shared network folders by injecting macros into existing Office documents
- USB drives and removable media: Less common but still viable, particularly in environments where users regularly exchange files via physical media
What It Does On Your Machine
When you enable macros in a document infected with Trojan:VBA/FV, the embedded VBA code executes immediately. The trojan's first action is typically to establish a foothold on your system by downloading and executing a secondary payload — often a more sophisticated piece of malware such as a banking trojan, ransomware, or remote access tool. This download occurs through PowerShell commands, Windows Script Host (wscript.exe or cscript.exe), or direct HTTP/HTTPS requests to attacker-controlled servers. The macro code is frequently obfuscated using character substitution, base64 encoding, or dynamic string assembly to evade antivirus detection.
Once the secondary payload is installed, Trojan:VBA/FV establishes persistence mechanisms to ensure the malware survives system restarts. Common techniques include creating registry entries in the Run or RunOnce keys, installing scheduled tasks that execute the malware at regular intervals, or modifying Office's Startup folder to load malicious add-ins whenever you open Word or Excel. Some variants inject themselves into the Normal.dotm template file, causing the trojan to execute every time you create a new document.
The trojan's activities after initial infection depend entirely on its payload, but typical behaviors include monitoring your keystrokes to capture banking credentials and passwords, stealing browser-stored credentials and cookies, taking screenshots when you visit financial websites, exfiltrating documents containing sensitive information, or installing cryptocurrency mining software that consumes your system's processing power. More aggressive variants may disable your antivirus software, modify firewall rules to allow unrestricted network access, or inject additional malicious code into running processes to hide their presence.
Many Trojan:VBA/FV infections function as "droppers" or "loaders" — their sole purpose is to download and install other malware families. This modular approach allows attackers to update the final payload without modifying the document itself, making it harder for security researchers to analyze the full scope of the threat. You might initially be infected with a simple information stealer, only to have ransomware installed days or weeks later when the attackers decide to monetize their access to your machine.
Manual Removal — Step by Step
Disconnect from Network Immediately
Before doing anything else, disconnect your computer from the internet by unplugging the ethernet cable or disabling Wi-Fi. This prevents the trojan from downloading additional payloads, communicating with its command-and-control server, or spreading to other devices on your network. Do not skip this step — many VBA trojans continue downloading malware components for hours or days after initial infection.
Boot into Safe Mode with Networking
Restart your computer and repeatedly press F8 (or Shift+F8 on newer systems) before Windows loads. Select "Safe Mode with Networking" from the menu. This loads Windows with only essential drivers and services, preventing most malware from executing automatically. Safe Mode with Networking allows you to download removal tools if needed, but keep your internet connection disabled until you've completed the initial cleanup steps.
Identify and Terminate Malicious Processes
Press Ctrl+Shift+Esc to open Task Manager. Look for suspicious processes, particularly any unfamiliar executables running from %TEMP%, %APPDATA%, or %LOCALAPPDATA% folders. Also check for PowerShell or wscript.exe running as child processes of Word or Excel. Right-click suspicious processes, select "Open file location," note the path, then end the process. Be cautious — terminating legitimate Windows processes can cause system instability.
Remove Persistence Mechanisms
Press Windows+R, type "regedit," and navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run. Look for unfamiliar entries, particularly those pointing to executables in temporary folders or folders with GUID names. Delete suspicious entries, but document what you remove in case you need to restore legitimate entries. Also check Task Scheduler (taskschd.msc) for scheduled tasks that run executables from suspicious locations — delete any that match the pattern of trojan artifacts.
Delete Malicious Files and Folders
Navigate to the file locations you identified in step 3. Delete the entire folder structure for any GUID-named folders in %LOCALAPPDATA%. Check %TEMP% and %APPDATA% for recently created executable files and delete them. Also examine C:\Users\[YourUsername]\AppData\Roaming\Microsoft\Word\STARTUP and delete any .wll or .dotm files you don't recognize. If you're uncertain whether a file is legitimate, move it to a quarantine folder on a USB drive rather than permanently deleting it.
Reset Office Macro Security Settings
Open Microsoft Word or Excel (if the trojan hasn't damaged the installation), go to File > Options > Trust Center > Trust Center Settings > Macro Settings. Select "Disable all macros with notification" — this is the safest setting for normal use. Also check File > Options > Add-ins, select "Manage: COM Add-ins" and click Go. Remove any unfamiliar add-ins. Finally, close Office and delete or rename your Normal.dotm template (it will regenerate cleanly) to remove any injected macro code.
Run Comprehensive Malware Scans
Reconnect to the internet and download Malwarebytes Free (from malwarebytes.com) and perform a full system scan. Also run Microsoft Defender Offline Scan (available through Windows Security settings) which can detect rootkits and deeply embedded threats. Consider running a second-opinion scanner like Emsisoft Emergency Kit. Allow each tool to complete its scan fully and quarantine everything it finds — don't selectively trust detections, as trojans often install multiple components.
Check Browser Extensions and Reset if Necessary
Many VBA trojans install browser extensions to steal credentials or redirect search results. Open each browser you use, check the extensions list, and remove anything unfamiliar or that you don't remember installing. If you notice persistent redirects or homepage changes even after removing extensions, reset your browser to default settings through the browser's settings menu. This removes all extensions, saved passwords, and customizations, so export your bookmarks first if possible.
Change All Passwords from a Clean Device
Because VBA trojans often install keyloggers or credential stealers, assume that any password you typed after infection is compromised. Use a different device (smartphone, tablet, or uninfected computer) to change passwords for email, banking, online shopping, and any work-related accounts. Enable two-factor authentication wherever possible. Do not change passwords from the infected machine until you've verified it's completely clean — otherwise the trojan will simply capture your new passwords.
Restart and Verify System Stability
Restart your computer normally (not in Safe Mode) and verify that the malicious processes don't reappear in Task Manager. Monitor network activity for unusual outbound connections. Open Event Viewer (eventvwr.msc) and check Application and System logs for error messages that might indicate incomplete removal. Test your Office applications to ensure they function normally. If you experience crashes, missing functionality, or unusual behavior, the infection may have damaged system files — run "sfc /scannow" from an elevated command prompt to repair Windows files.
Prevention
- Disable macros by default: Configure Microsoft Office to "Disable all macros with notification" or "Disable all macros except digitally signed macros" in Trust Center settings. Never enable macros in documents from unknown sources, and be suspicious even of documents from known contacts — their accounts may be compromised.
- Verify email attachments before opening: Contact the sender through a separate communication channel (phone call, text message, not email reply) to confirm they actually sent the attachment. Be especially wary of emails with urgent language, grammatical errors, or generic greetings like "Dear Customer" rather than your name.
- Keep Office and Windows fully updated: Microsoft regularly patches vulnerabilities that malware exploits. Enable automatic updates for both Windows and Office, and install updates as soon as they're available. Many VBA trojans exploit known vulnerabilities that have been patched for months or years.
- Use reputable antivirus with real-time protection: Install antivirus software that includes behavioral detection and real-time scanning. Windows Defender provides adequate baseline protection, but consider commercial solutions like Kaspersky, Bitdefender, or ESET for business environments. Ensure the antivirus updates its definitions daily.
- Implement email filtering and attachment scanning: Use email services that automatically scan attachments for malware and block suspicious file types. Configure your email client or server to quarantine .doc, .docm, .xls, .xlsm files from external senders until you verify their legitimacy. Many business email providers offer these features as part of their security suite.
- Educate yourself and employees about phishing tactics: Learn to recognize common social engineering techniques — urgent language, requests for immediate action, offers that seem too good to be true, emails supposedly from banks or government agencies asking you to open attachments. Conduct regular security awareness training if you manage a business network.
- Use standard user accounts for daily work: Don't operate with administrator privileges for routine tasks. Many trojans require elevated privileges to install persistence mechanisms. Using a standard user account limits the damage malware can do, even if it gets executed.
- Maintain regular backups on disconnected media: Keep current backups of important files on an external hard drive that you disconnect after each backup, or use cloud backup services with versioning capability. This won't prevent infection, but it gives you a recovery option if ransomware encrypts your files or the trojan corrupts your data.
Bring It In
Trojan:VBA/FV infections rarely exist in isolation — the macro-based trojan is usually just the entry point for more sophisticated malware that can be difficult to detect and remove completely. While the manual removal steps above can eliminate the obvious components, hidden payloads, modified system files, or persistent backdoors often remain. Our technicians use specialized forensic tools to identify all infection artifacts, verify complete removal, and repair any damage the malware caused to Windows components or installed applications.
We're located in Roswell, Georgia, and offer same-day service for malware removal in most cases. Bring your infected machine to our shop at 1279 Hightower Trail or call us at (770) 695-6672 to discuss your situation. We'll provide a clear assessment of the infection's scope, explain exactly what we'll do to remove it, and give you an upfront price quote before beginning any work. We also service both PCs and Macs, and we can help secure your network if you're concerned about the infection spreading to other devices in your home or office.