TROJ_SUURCH.AO


 ALIASES:

Trojan:Win32/Ertfor.D (Microsoft); ErtFor.b (McAfee); Downloader (Symantec); Trojan-Downloader.Win32.Suurch.bvx (Kaspersky); Trojan.Win32.Ertfor.B.1 (v) (Sunbelt); Gen:Trojan.RegistryDisabler.biadau0UGDl (FSecure)

 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.

It disables Task Manager, Registry Editor, and Folder Options.

  TECHNICAL DETAILS

File Size:

20,784 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

01 Jan 2013

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:

  • %User Temp%\avp.exe
  • %User Temp%\sysedit.exe
  • %User Temp%\cmd.exe
  • %User Temp%\wininst.exe

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
hsf8973uhs87fdiufs3rfd = "%User Temp%\avp.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
hsf8973uhs87fdiufs3rfd = "%User Temp%\sysedit.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
hsf8973uhs87fdiufs3rfd = "%User Temp%\cmd.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
hsf8973uhs87fdiufs3rfd = "%User Temp%\wininst.exe"

Other System Modifications

This Trojan deletes the following files:

  • %User Temp%\avp.exe
  • %User Temp%\sysedit.exe
  • %User Temp%\cmd.exe
  • %User Temp%\wininst.exe

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\SystemRestore

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
UserID = "1CDD73144B9A980"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\New Windows
PopupMgr = "yes"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\SystemRestore
DisableSR = "1"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "0"

(Note: The default value data of the said registry entry is 2.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "0"

It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\skaioejiesfjoee.tmp

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}v.net/rz/mn.php?ver=H1
  • http://{BLOCKED}v.netrz/report.php

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Enable Registry Editor, Task Manager, and Folder options

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

Step 4

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\Policies\Microsoft\Windows NT
    • SystemRestore
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
    • System

Step 5

Delete this registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • hsf8973uhs87fdiufs3rfd = "%User Temp%\avp.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • hsf8973uhs87fdiufs3rfd = "%User Temp%\sysedit.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • hsf8973uhs87fdiufs3rfd = "%User Temp%\cmd.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • hsf8973uhs87fdiufs3rfd = "%User Temp%\wininst.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • UserID = "1CDD73144B9A980"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\New Windows
    • PopupMgr = "yes"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\SystemRestore
    • DisableSR = "1"

Step 6

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "0"
      To: Hidden = ""2""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = "1"
      To: HideFileExt = ""1""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • SuperHidden = "0"

Step 7

Search and delete this file

[ Learn More ]
There may be some 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.
  • %User Temp%\skaioejiesfjoee.tmp

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_SUURCH.AO. 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.

Step 9

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Temp%\avp.exe
  • %User Temp%\sysedit.exe
  • %User Temp%\cmd.exe
  • %User Temp%\wininst.exe


Did this description help? Tell us how we did.