Threat Description

Small.avu

Details

Aliases: Small.avu, Trojan-Downloader.Win32.Small.avu, W32/Small.avu, Backdoor.Win32.Dumador.bl, Backdoor.Win32.Dumadoor.bl
Category: Malware
Type:
Platform: W32

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 e-mail messages. The trojan downloader is programmed to download and run a Dumador backdoor variant from a website.



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



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 e-mail 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.



Detection


The downloaded Dumador backdoor variant is detected as 'Backdoor.Win32.Dumador.bl' with the following F-Secure Anti-Virus update:
Detection Type: PC
Database: 2005-04-27_05

The trojan downloader is detected as 'W32/Small.avu' with the following F-Secure Anti-Virus update:
Detection Type: PC
Database: 2005-05-24_05



Description Created: Alexey Podrezov, May 24th, 2005


SUBMIT A SAMPLE

Suspect a file or URL was wrongly detected? Submit a sample to our Labs for analysis

Submit Now

Give And Get Advice

Give advice. Get advice. Share the knowledge on our free discussion forum.

Learn More