Files Detected as Infected After Week of Being Installed?

Dreazy

Question is above. I downloaded an .exe file on my computer (already submitted to Bitdefenders Labs for review) about a week ago. After initial scans and multiple system scans over the week, I was getting nothing and told that my system was clean. Suddenly, the file was flagged for a Trojan last night. Any idea on why it has taken a week for detection?

Flexx

https://community.bitdefender.com/en/discussion/100815/files-detected-as-infected-after-week-of-being-installed

There are several reasons why Bitdefender took a week to flag the .exe file as a Trojan:

1. Newly discovered threat: The Trojan might be a newly discovered threat, and Bitdefender's initial database didn't have a signature for it. After further analysis and updates, the signature was added, and the file was flagged.
2. Behavioral detection: Bitdefender might have been monitoring the file's behavior, and only after a week, it exhibited malicious behavior that triggered the detection.
3. Cloud-based analysis: Bitdefender's cloud-based analysis might have taken time to complete, and the results were only recently updated, leading to the detection.
4. Signature updates: Bitdefender's signature database might have been updated with new definitions, allowing the detection of the Trojan.
5. Sandbox analysis: The file might have been analyzed in a sandbox environment, which takes time, and the results were only recently available.
6. Machine learning model updates: Bitdefender's machine learning models might have been updated, improving detection capabilities and leading to the flagging of the file.

Also, when you sent the file to the malware research team, they may have found it malicious and created a detection for it.

Regards