TROJ_DLOAD.RAM

October 13, 2012

ALIASES:

TrojanDownloader:Win32/Agent.QP (Microsoft); [4.nsis]:Generic StartPage.am, [6.nsis]:Generic Downloader.ln (McAfee); Downloader.Malscript (Symantec); ARC:NSIS, [data0001]:Trojan-Downloader.Win32.NSIS.no (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)

PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

OVERALL RISK RATING:

DAMAGE POTENTIAL:

DISTRIBUTION POTENTIAL:

REPORTED INFECTION:

Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes

OVERVIEW

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

TECHNICAL DETAILS

File Size:

1,505,505 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 May 2012

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan creates the following folders:

%System Root%\DOCUME~1
%System Root%\DOCUME~1\ADMINI~1
%User Profile%\LOCALS~1
%User Temp%\nsj2.tmp
%Program Files%\jishu_065643
%Program Files%\jishu_065643\ImgCache
%Program Files%\jishu_065643\sc
%Program Files%\soft065643
%User Profile%\CryptnetUrlCache\MetaData
%User Profile%\Microsoft\CryptnetUrlCache
%User Profile%\CryptnetUrlCache\Content
%User Profile%\Internet Explorer\Quick Launch

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{26923b43-4d38-484f-9b9e-de460746276c}
IsInstalled = "0"

Other System Modifications

This Trojan deletes the following files:

%User Temp%\nso1.tmp
%User Temp%\nsj2.tmp
%Program Files%\soft065643\b_0643.vbs
%Program Files%\soft065643\300.bat
Internet Explorer.lnk
Launch Internet Explorer Browser.lnk

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Program Files% is the default Program Files folder, usually C:\Program Files.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\Certificates

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\CRLs

HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\TrustedPublisher\CTLs

HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher

HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher\
Certificates

HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher\
CRLs

HKEY_CURRENT_USER\Software\Policies\
Microsoft\SystemCertificates\TrustedPublisher\
CTLs

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\AuthRoot\Certificates\
4EFCED9C6BDD0C985CA3C7D253063C5BE6FC620C
Blob = "{random values}"