Name :	Nilage.AUT
Size:	91,224 bytes or 137,216 bytes
Category:	Trojan
Type:	Trojan
Platform:	Win32
Date of Discovery:	November 22, 2006

Nilage.AUT, a variant of Nilage, is a Trojan. Nilage.AUT drops and loads a password stealing component on an infected system and steals sensitive information from an infected computer. Nilage.AUT attempts to download and install other malware to the system.

Automatic Disinfection

Usually standalone malware (backdoors, worms, trojans, etc.) is automatically removed by F-Secure Anti-Virus (FSAV) starting from version 5.40. Malware files get automatically renamed by FSAV, so they can not be started any more. In some rare cases, when automatic disinfection is not possible, a user can select disinfection action by him/herself to make FSAV rename or delete an infected file. In some special cases it is recommended to use specific disinfection tools provided by F-Secure. They can be downloaded from our ftp site:

ftp://ftp.f-secure.com/anti-virus/tools/

F-Secure Anti-Virus can be purchased from our webshop or from our authorised distributors. A trial version F-Secure Anti-Virus, limited to 30 days, can be downloaded from our website:

http://www.f-secure.com/download-purchase/

All the latest versions of FSAV can download anti-virus database updates automatically. However, these updates can be also downloaded and installed manually from our web or ftp sites:

http://www.f-secure.com/download-purchase/updates.shtml


Manual Disinfection

To manually disinfect standalone malware (backdoors, worms, trojans, etc.) it's usually enough to delete all infected files from a computer and to restart it. Active malware files are usually locked by operating system so different disinfection approaches are required for different operating systems.
Please note that manual disinfection is a risky process, so it is recommended only for advanced users.

If Windows 95, 98 and ME operating system is used, it is recommended to restart a computer from a bootable system diskette and to delete an infected file from command prompt. For example if a malicious file named ABC.EXE is located in Windows folder, it is usually enough to type the following command at command prompt:

DEL C:\WINDOWS\ABC.EXE

and to press Enter. After that an infected file will be gone. If Windows NT, 2000 or XP is used, a malicious file has to be renamed with a different extension (for example .VIR) and then a system has to be restarted. After restart a renamed malicious file will no longer be active and it can be easily deleted manually.


Malware Disinfection Tools

F-Secure provides disinfection tools for certain malware. These tools can be downloaded from this webpage:

http://www.f-secure.com/download-purchase/tools.shtml

ftp://ftp.f-secure.com/anti-virus/tools/


Windows System Restore Issues

If Windows ME or XP is used, it is recommended to disable System Restore feature of these operating systems to prevent a computer from re-infection by an already removed malware. The fact is that System Restore feature of these operating systems might save an infected file into the special folder and copy it back to a hard drive it every time it's been renamed or deleted by F-Secure Anti-Virus or by a user. Instructions on how to disable System Restore feature are here:

Windows ME:
http://www.f-secure.com/v-descs/sfc_dis.shtml

Windows XP:
http://www.f-secure.com/v-descs/sfc_dis1.shtml

It is recommended to re-enable System Restore after disinfection in order to restore stable system configuration in the future, if any crash or incompatibility issue occurs.


Failed Disinfection

In some cases F-Secure Anti-Virus might not disinfect a system automatically. In this case please visit our Support pages:

http://support.f-secure.com/enu/home/virusproblem/howtoclean/

Once Nilage.AUT has been executed it will drop the following file:



It will register its DLL component as a Browser Helper Object (BHO) so that every time Internet Explorer is loaded, Nilage.AUT is also loaded:



Everytime the DLL component is executed, it will drop and execute its .EXE component in the following path and filename:



Payload

The main payload of Nilage.AUT is to steal information regarding Online games such as Lineage and Maple Story. Both are popular in Korea.

Nilage.AUT includes keylogging functionality.

Nilage.AUT steals information with regards to the following details:

Class Names



Running Process Names



Visited URL:



The gathered information including username and passwords are stored in this hard coded path and filename:



Gathered information is sent to the hacker by posting the file to the following links:



It also gathers data from these links for it malicious acts:



Asside from being a password stealer, Nilage.AUT is also a downloader. It downloads and executes other malware from the following link:


And saves the download to the following path name filename:


To ensure that an error will not occur, it will delete the existing file before downloading the new file.

Note: As of this writing the link above is no longer available.


Nilage.AUT does not fully support all operating system:



Nilage.AUT is coded using Borland Delphi.