Trojan-Downloader.Win32.Small.dcj

Technical Details

This Trojan downloads files via the Internet without the user’s knowledge or consent. It is a Windows PE EXE file. The file is 3,072 bytes in size. It is written in Assembler.

Installation

Once launched, the Trojan registers itself in the system registry:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"WinMedia" = "name_Trojan_file"

This ensures that the Trojan will be launched each time Windows is booted on the victim machine.

The Trojan also creates a unique identifier, “0b.bot” to flag its presence in the system.

Payload

The Trojan waits for the victim machine to connect to the Internet. It then connects to 245.47.***.216 on port 2514. (The port and the server address may differ according to the variant of the Trojan. The Trojan receives other malicious code from the server.

It then launches “%system%\servises.exe", injects the malicious code got from the server into the process, and passes control to it.

Removal instructions

1. Use Task Manager to terminate the Trojan process.
2. Delete the original Trojan file (the location will depend on how the program originally penetrated the victim machine).
3. Delete the following registry keys:
   [HKCU\Software\Microsoft\Windows\CurrentVersion\Run] "WinMedia" = "name_Trojan_file"
4. Update your antivirus databases and perform a full scan of the computer (download a trial version of Kaspersky Anti-Virus)