Microsoft Defender antivirus marks a text file with the words "This content is no longer available" as a trojan

Microsoft Defender, the built-in antivirus for Windows, is considered reliable enough that an average user does not need a third-party application. An error, detected by Twitter user X yappy, demonstrates that sometimes Defender performs its function too diligently.

A text file with the phrase "This content is no longer available." can trigger a false positive by the antivirus. Simply creating a text file with this content and any name in Notepad and saving it can cause Microsoft Defender to instantly flag it as a trojan and remove it from the system (the news author was not successful). If other characters are added to the file, no false detection occurs.

After preliminary research, yappy and several other Twitter users concluded that the cause of the false positive was a SHA-256 collision. Currently, most commentators agree that the text string has been used in several previous threats, causing Windows Defender to flag it.

This error is not the first issue with Defender. In fact, Microsoft actually broke it in 2020 due to an update error, and another critical error was fixed in 2019. However, apart from these instances, Microsoft Defender can still be considered a decent antivirus.

Source: Tom`s Hardware