Classification

Category :

Malware

Type :

Trojan-Downloader

Aliases :

Tiny.BM, Tiny.BM

Summary

Tiny.BM, a variant of Tiny, is a Trojan. Tiny.BM downloads and runs a file from a malicious website.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

Once Tiny.BM has been executed it will decrypt strings such as the following, which are required for its malicious activities:

  • API names
  • URL
  • Filename

Note: decryption key is 0x56

Once decrypted, Tiny.BM will attempt to download from the following site:

  • https://69.50.190.164/traff/sb8[BLOCKED].exe

It will save the file in the following hard-coded path and filename:

  • %temp%\~dfte14.tmp

After downloading, it will check if the file size of the downloaded file is equal to 449,024 bytes. If it is the exact size, it will then execute the downloaded file. If the file size is different, it will repeatedly retry downloading until file size matches.

Note: as of this writing, the URL link above is no longer active.

Some samples of Tiny.BM have embedded malware that when extracted is detected as Trojan-Downloader.Win32.Small.cxx.