Avast detected ELF Mirai Downloader but is unable to remove it

Part 1 of 2

There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX  Foundation and Permission Limitation. 

Additionally, and specific to Big Sur macOS 11,  Monterey macOS 12, Ventura macOS 13, the Operating System resides in a Sealed and Read Only Volume that can not be opened by the User and protects against from “ Bad Actor “ Software.

The Only thing this Antivirus software is protecting is the Bank Account of the Developers and for zero return to the User aside from the problems this software creates.

AntiVirus Developers purposefully Market their product to create a “ Fear Factor “. In so doing, creating a False Need for their Product.

The The Built in Security  is all that is required to protect the computer.

Part 2 of 2

Any of the below should be removed as per Developers Instructions 

This will include BitDefender , 

This will included Norton Antivirus , Sophos Av Software

Intego AntiVirus, McAfee, Avast AntiVirus

Read some of the posting and arrive at your own conclusions.

dustinhenderson wrote:

This happened on my Mac. I ran an Avast deep scan which came up with malware found in some macOS system files - its called ELF:MiraiDownloader-OG[Drp]. I tried to remove it using Avast but it was unable to remove it. I went into the folder it was detected in but I don't see any way to delete it either.

I further upgraded my OS to Monterey and the same this shows up again after a scan.

Below is a screenshot of what shows up on Avast. Any idea that this is? Should I be worried?

To make you feel like you are getting your "moneys worth"—third party AV has to present something to you, weather it directly effects macOS or not...

Third party AntiVirus is not recommended— it typically does nothing but add issues to the macOS and competes directly with Apple’s own built in security:

macOS - Security - Apple macOS - Security - Apple

Apple Platform Security - Apple Apple Platform Security - Apple Support

Uninstall any and all third party Antivirus, Cleaners, Optimizers, VPN, speeder uppers....

if in doubt search the developers website or contact their: Support/Help/FAQ/Known issues/compatibility/updates/uninstaller

Contact a third-party vendor - Apple Support

Contact a third-party vendor - Apple Support

Those are legitimate macOS files installed on the read-only macOS System partition. Since the developers of A/V products did not develop macOS, when they encounter something they don't understand, they label it as some form of malware — as leroydouglas mentions — to justify their existence (and ignorance).

We have seen posts like this from just about every A/V product over the years where users panic when they see these false positives. Best to let macOS's own security deal with its protection and thoroughly remove any third-party anti-virus product for its less than limited value.

Welcome