Don't Open .xmpeg Files Before Reading This

You downloaded a file with the .xmpeg extension and something feels off. Maybe a torrent told you to install a "special codec" to watch it. Maybe Windows has no idea what to do with it. Either way - your instincts are right to be suspicious.
 

In August 2025, Kaspersky researchers confirmed what many users already feared.

The .xmpeg file format is being actively weaponized by the Efimer Trojan to steal cryptocurrency and compromise Windows systems through fake codec installers.

This guide will help you figure out whether your .xmpeg file is a legitimate (if obscure) video file - or a trap.

A .xmpeg file is not a recognized video standard. Unlike standard MPEG formats (.mp4, .mpg, .mpeg), the .xmpeg extension has no official specification behind it.

There are only two realistic explanations for a .xmpeg file on your computer:

1. A renamed MPEG video. Older tools like Xmpeg (a legitimate but discontinued MPEG converter from the early 2000s) sometimes saved files with this extension. In this case, the file is just an ordinary MPEG video with an unusual name.

2. Malware bait. This is now the far more common scenario. Attackers deliberately use the unfamiliar .xmpeg extension to force victims into installing a fake "codec" or "special player" that is actually a Trojan.

How the Efimer Trojan Scam Works

Understanding the attack pattern helps you recognize it instantly. Here's the typical setup documented by Kaspersky:

1. You download a torrent that claims to be a popular movie or show.
2. The torrent folder contains a large .xmpeg file (the supposed "movie"), a short .mp4 video or readme explaining you need a "special codec", and an executable file like xmpeg_player.exe.
3. Some versions include a .bat file that silently disables Windows Defender for the folder.
4. Running the "player" installs the Efimer Trojan, which steals crypto wallets, adds itself to startup, and can even compromise WordPress sites to spread further.

The .xmpeg file itself may contain no video data at all. It exists purely to create confusion and push you toward running the malicious executable.

How to Safely Handle a .xmpeg File

If you already have a .xmpeg file and want to check whether it's legitimate, follow these steps in order.

Step 1: Check What Came With It

Look at the folder contents. If you see any .exe, .bat, or .zip files alongside the .xmpeg file - delete everything immediately. Legitimate video files never require you to run an installer.

If the .xmpeg file came from a torrent with a "readme" telling you to install something, it's almost certainly the Efimer scam.

Step 2: Scan Before Touching

Before doing anything else, scan the file with updated antivirus software. Upload it to a free scanner if you want a second opinion. Do not rename or open the file until it passes a scan.

Step 3: Try Renaming the Extension

If the file passed your scan, try renaming it from .xmpeg to .mpg or .mpeg.

Then open it with VLC Media Player, which can handle virtually any video format without requiring additional codecs.

If VLC plays the file normally after renaming, you had a legitimate MPEG video with a non-standard extension.

You can also install the K-Lite Codec Pack for broader format support across all your media players.

Step 4: Convert It

If renaming doesn't work but the file appears clean, try converting it to .mp4 using one of these free tools:

• HandBrake - best for beginners, simple drag-and-drop interface.
• FFmpeg - command-line powerhouse, use: ffmpeg -i file.xmpeg -c:v libx264 output.mp4

If neither tool can read the file, it likely contains no valid video data - further confirming it was malware bait.

Step 5: Inspect With a Hex Editor (Advanced)

For tech-savvy users, opening the file in a hex editor like ImHex reveals its true nature.

Legitimate MPEG files start with specific byte signatures (00 00 01 BA for MPEG-PS or 00 00 01 B3 for MPEG video). If you see random data or embedded PE headers instead, the file is not a video.

The "Copyright Protected by xmpeg Codec" Error

Some users report seeing this message:

"The video is protected from copyright by the xmpeg codec"

This is almost always part of the scam. There is no legitimate DRM system called "xmpeg codec".

This fake error message is designed to convince you that you need to download and install something - which is exactly how the Efimer Trojan gets onto your system.

If you see this message, do not follow any instructions to install codec packs, players, or plugins. Close the file and delete it.
 

Quick Decision Guide

Should You Open That .xmpeg File?

DELETE IT if: It came from a torrent with .exe, .bat, or .zip files alongside it. Someone emailed it to you from an unknown address. Any message tells you to "install a codec" to view it.

It MIGHT be safe if: You created it yourself with older video software. It came from a source you personally trust. VLC plays it fine after renaming to .mpg.

When in doubt: Delete the file. No single video file is worth a compromised system.

Why This Matters in 2026

The .xmpeg scam exploits a technique as old as the internet - fake codec installers. But the Efimer Trojan makes it dangerous in a new way.

Beyond just infecting your PC, it targets cryptocurrency wallets and uses your system to compromise websites and spread to other victims.

Kaspersky detected it impacting users in over 10 countries. The attack is active, evolving, and specifically designed to look convincing.

The best defense is simple: never install software just because a file tells you to. Use trusted, well-known players like VLC and established codec packs from verified sources. If a file requires a "special player" you've never heard of - walk away.