Hackers are at it again. This time they are using phony Microsoft Teams installers to spread a nasty program called Oyster malware. And they are all doing this via sneaky online ads (malvertising) that look completely safe, but are not. To understand it better, let’s break it down into simple terms.
When users type in "Microsoft Teams download," scamsters place their advertising at the top of the results. The ad will take the person to an imitation website that appears to be Microsoft's authentic page.
The red flag is that the false installer is signed with true security certificates so it appears to be trustworthy.
Upon opening the Installer, the program secretly places a bad file called CaptureService.dll inside the system and creates a scheduled task to launch that every 11 minutes, so it is always present.
• The advertisements presented in search engines seem safe, but they may be traps.
• Signed files appear official and users do not think twice.
• IT admins are major targets because if hackers get these, they probably have access to the entire network.
• Download from official Microsoft website (don't click on ads).
• Avoid sponsored links when searching for apps.
• Use antivirus or endpoint protection for additional protection against sneaky tasks.
After I install software, I check my system for strange files or scheduled jobs I didn't create.
So, next time you need Teams, you or your friend should skip the ad and go right to the real Microsoft site. Better safe than sorry!
What is Oyster Malware?
Think of Oyster malware as a hidden backdoor. Once it creeps into your computer, hackers can:- Run commands under the radar
- Steal your files
- Add more harmful programs
How the Trick Works
Fake ads appearing on search enginesWhen users type in "Microsoft Teams download," scamsters place their advertising at the top of the results. The ad will take the person to an imitation website that appears to be Microsoft's authentic page.
The Fake Installer
From that bogus site, you download an item called MSTeamsSetup.exe. Sounds legit right? That's the name Microsoft calls its true Teams app.The red flag is that the false installer is signed with true security certificates so it appears to be trustworthy.
Upon opening the Installer, the program secretly places a bad file called CaptureService.dll inside the system and creates a scheduled task to launch that every 11 minutes, so it is always present.
Why this Scam Works
• People have faith in large brands such as Microsoft.• The advertisements presented in search engines seem safe, but they may be traps.
• Signed files appear official and users do not think twice.
• IT admins are major targets because if hackers get these, they probably have access to the entire network.
How to Protect Yourself
Here are a few easy tips that I personally use:• Download from official Microsoft website (don't click on ads).
• Avoid sponsored links when searching for apps.
• Use antivirus or endpoint protection for additional protection against sneaky tasks.
After I install software, I check my system for strange files or scheduled jobs I didn't create.
Key Take Away
- Fake ads = Fake Teams download
- Oyster malware = Hackers get control
- Real-looking certificates = False sense of safety
- Stays alive by running every 11 minutes
- Main goal = Attack companies and IT people
Final thoughts
It’s crazy how something this simple can fool so many people. But it shows one thing: always check the website before you download anything. One little mistake can open you up to a lot of headaches.So, next time you need Teams, you or your friend should skip the ad and go right to the real Microsoft site. Better safe than sorry!
