TROJ_AGENT.ISI

April 22, 2011
 Analysis by: Karl Dominguez
 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 may be downloaded by other malware/grayware/spyware from remote sites. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

It adds registry entries to enable its automatic execution at every system startup.

  TECHNICAL DETAILS

File Size:

17,694 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Jan 2007

Payload:

Steals information

Arrival Details

This Trojan may be downloaded by other malware/grayware/spyware from remote sites.

It may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System%\Sysinfo.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 is injected into the following processes running in memory:

  • Explorer.exe

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\{18690D04-34EB-1B4C-A68D-ADD6A122F297}
StubPath = %System%\Sysinfo.exe

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{18690D04-34EB-1B4C-A68D-ADD6A122F297}

Dropping Routine

This Trojan drops the following file(s), which it uses for its keylogging routine:

  • %System%\Sysinfo

(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.)

Drop Points

Stolen information is uploaded to the following websites:

  • {BLOCKED}zo.com

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

4.176.04

FIRST VSAPI PATTERN DATE:

11 Jan 2007

Step 1

For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer"s registry.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
    • {18690D04-34EB-1B4C-A68D-ADD6A122F297}

Step 4

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result. %System%\Sysinfo

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_AGENT.ISI If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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