TROJ_SMALL.JTM

 Analysis by: Christopher Daniel So

 ALIASES:

Trojan Horse (Symantec), Generic.dx (McAfee), Trojan.Win32.Small.bpu (Kaspersky)

 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats. As of this writing, the said sites are inaccessible.

It opens a hidden Internet Explorer window.

  TECHNICAL DETAILS

File Size:

59,904 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

02 Aug 2008

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 drops the following copies of itself into the affected system:

  • %System%\Spooler.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It drops the following component file(s):

  • %Windows%\qqssdll.dll

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Print Spooler = "%System%\Spooler.exe"

Download Routine

This Trojan connects to the following malicious URLs:

  • http://{BLOCKED}g.{BLOCKED}t.com/WB/yguang/tj.html
  • http://{BLOCKED}g.{BLOCKED}t.com/WB/yguang/msg2.txt

As of this writing, the said sites are inaccessible.

Other Details

This Trojan opens a hidden Internet Explorer window.