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TROJ_DLOADER.RYJ

May 31, 2013
 ALIASES:

TrojanDownloader:Win32/Delf.TE (Microsoft); Generic Downloader.x!gls (McAfee); Trojan.Win32.Generic.pak!cobra (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:

1,009,664 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Oct 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:

  • %User Temp%\is-7RCG1.tmp
  • %User Temp%\is-SUGLM.tmp
  • %User Temp%\is-SUGLM.tmp\_isetup
  • %Program Files%\filenolja

(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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

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
FileNolja = "%Program Files%\filenolja\Upgrade.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
Inno Setup: Setup Version = "5.4.3 (a)"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
Inno Setup: App Path = "%Program Files%\filenolja"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
InstallLocation = "%Program Files%\filenolja"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
Inno Setup: Icon Group = "ÀÚµ¿ ¾÷µ¥ÀÌÆ®"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
Inno Setup: User = "Wilbert"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
Inno Setup: Language = "Korean"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
DisplayName = "Windows FileNolja Update"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
DisplayIcon = "%Program Files%\filenolja\unins000.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
UninstallString = "%Program Files%\filenolja\unins000.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
QuietUninstallString = "%Program Files%\filenolja\unins000.exe /SILENT"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
DisplayVersion = "1.0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
NoModify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
NoRepair = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
InstallDate = "20121009"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
MajorVersion = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
MinorVersion = "0"

It deletes the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1

Dropping Routine

This Trojan drops the following files:

  • %Temporary Internet Files%\AUSetup.exe
  • %User Temp%\is-7RCG1.tmp\AUSetup.tmp
  • %User Temp%\is-SUGLM.tmp\_isetup\_RegDLL.tmp
  • %User Temp%\is-SUGLM.tmp\_isetup\_shfoldr.dll
  • %Program Files%\filenolja\unins000.dat
  • %Program Files%\filenolja\is-0TOO5.tmp
  • %Program Files%\filenolja\is-3IIRL.tmp

(Note: %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista and 7.. %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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

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\Windows\CurrentVersion\Uninstall
    • ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • FileNolja = "%Program Files%\filenolja\Upgrade.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • Inno Setup: Setup Version = "5.4.3 (a)"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • Inno Setup: App Path = "%Program Files%\filenolja"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • InstallLocation = "%Program Files%\filenolja"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • Inno Setup: Icon Group = "ÀÚµ¿ ¾÷µ¥ÀÌÆ®"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • Inno Setup: User = "Wilbert"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • Inno Setup: Language = "Korean"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • DisplayName = "Windows FileNolja Update"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • DisplayIcon = "%Program Files%\filenolja\unins000.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • UninstallString = "%Program Files%\filenolja\unins000.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • QuietUninstallString = "%Program Files%\filenolja\unins000.exe /SILENT"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • DisplayVersion = "1.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • NoModify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • NoRepair = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • InstallDate = "20121009"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • MajorVersion = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1
    • MinorVersion = "0"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %Temporary Internet Files%\AUSetup.exe
  • %User Temp%\is-7RCG1.tmp\AUSetup.tmp
  • %User Temp%\is-SUGLM.tmp\_isetup\_RegDLL.tmp
  • %User Temp%\is-SUGLM.tmp\_isetup\_shfoldr.dll
  • %Program Files%\filenolja\unins000.dat
  • %Program Files%\filenolja\is-0TOO5.tmp
  • %Program Files%\filenolja\is-3IIRL.tmp

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\is-7RCG1.tmp
  • %User Temp%\is-SUGLM.tmp
  • %User Temp%\is-SUGLM.tmp\_isetup
  • %Program Files%\filenolja

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOADER.RYJ. 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 8

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • ÀÚµ¿ ¾÷µ¥ÀÌÆ®_is1


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