Classification

Category :

Malware

Type :

-

Aliases :

Small.avu, Trojan-Downloader.Win32.Small.avu, W32/Small.avu, Backdoor.Win32.Dumador.bl, Backdoor.Win32.Dumadoor.bl

Summary

We got several reports about the 'Small.avu' trojan downloader on May 24th, 2005. According to those reports the trojan was spammed to a large number of people in email messages. The trojan downloader is programmed to download and run a Dumador backdoor variant from a 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

The trojan downloader's file is a PE executable 1648 bytes long, packed with FSG file compressor.

According to the reports the trojan downloader was spammed with email messages that looked like that:

Subject:

ISTE RUS CITIRLAR

Body:

SELAM BEYLER!!!!
NATASHALAR SIZLERI BEKLIYOR::::..
HERZAMAN BIR RUSYALI NATASHA ILE SEX DOLU BIR GECE YASAMAYI HEPINIZ
DUSUNMUSSUNUZDUR.ISTE FIRSAT.BU GERCEKLESEBILIR,YUZLERCE RUS KIZI
TURKIYEYE GELMEK ICIN SIZLERI BEKLIYOR.7/24 SIZINLE VE EMRINIZDE.
MAILIMIZDE KIZLARIMIZIN RESIMLERINI GOREBILIRSINIZ.BEGENIN,SECIN.VE SIZIN OLSUN.
GERISI SIZE KALMIS:::.

The trojan downloader's file was attached to these messages as 'ATTACH.RAR.EXE' file. When this file is run by a user, it attempts to download and run a variant of Dumador backdoor from the following website:

tr.distributed-hosting.com

We have reported the abuse to the ISP that hosts that website.