Analysis by: Rika Joi Gregorio
ALIASES:

Rogue:Win32/FakeRean(Microsoft), a variant of Win32/Kryptik.ARQY trojan(Eset), W32/FakeAlert.GWW!tr(Fortinet)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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 modifies registry entries to disable the Windows Firewall settings. This action allows this malware to perform its routines without being deteted by the Windows Firewall.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 323,782 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 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 and executes them:

  • %AppDataLocal%\{random}.exe

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CLASSES_ROOT\.exe\shell

HKEY_CURRENT_USER\Software\Classes\
.exe

HKEY_CURRENT_USER\Software\Classes\
exefile

It adds the following registry entries:

HKEY_CLASSES_ROOT\.exe\shell\
open\command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%1" %*"

HKEY_CURRENT_USER\Software\Classes\
.exe\shell\open\
command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%1" %*"

HKEY_CURRENT_USER\Software\Classes\
exefile\shell\open\
command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%1" %*"

It modifies the following registry entries:

HKEY_CLASSES_ROOT\exefile\shell\
open\command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%1" %*"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\FIREFOX.EXE\shell\
open\command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe""

(Note: The default value data of the said registry entry is %Program Files%\Mozilla Firefox\firefox.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\FIREFOX.EXE\shell\
safemode\command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"

(Note: The default value data of the said registry entry is "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode.)

HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\IEXPLORE.EXE\shell\
open\command
(Default) = ""%AppDataLocal%\{random}.exe" -a "%Program Files%\Internet Explorer\iexplore.exe""

(Note: The default value data of the said registry entry is %Program Files%\Internet Explorer\iexplore.exe.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = 1

(Note: The default value data of the said registry entry is 0.)

It modifies the following registry entries to disable the Windows Firewall settings:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = 1

(Note: The default value data of the said registry entry is 0.)

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
EnableFirewall = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DoNotAllowExceptions = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DisableNotifications = 0

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}tines.name/data.exe

It saves the files it downloads using the following names:

  • %User Temp%\{random}.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:

  • {BLOCKED}.{BLOCKED}.104.244
  • {BLOCKED}.{BLOCKED}.38.162

It deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.644.01
FIRST VSAPI PATTERN DATE: 07 Jan 2013
VSAPI OPR PATTERN File: 9.645.00
VSAPI OPR PATTERN Date: 08 Jan 2013

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_CLASSES_ROOT\.exe
    • shell
  • In HKEY_CURRENT_USER\Software\Classes
    • .exe
  • In HKEY_CURRENT_USER\Software\Classes
    • exefile

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\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • EnableFirewall = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • DoNotAllowExceptions = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
    • DisableNotifications = 1

Step 5

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_CLASSES_ROOT\exefile\shell\open\command
    • From: (Default) = ""%AppDataLocal%\{random}.exe" -a "%1" %*"
      To: (Default) = "%1" %*
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\shell\open\command
    • From: (Default) = ""%AppDataLocal%\{random}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe""
      To: (Default) = %Program Files%\Mozilla Firefox\firefox.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\shell\safemode\command
    • From: (Default) = ""%AppDataLocal%\{random}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"
      To: (Default) = "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\IEXPLORE.EXE\shell\open\command
    • From: (Default) = ""%AppDataLocal%\{random}.exe" -a "%Program Files%\Internet Explorer\iexplore.exe""
      To: (Default) = %Program Files%\Internet Explorer\iexplore.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AntiVirusDisableNotify = 1
      To: AntiVirusDisableNotify = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: FirewallDisableNotify = 1
      To: FirewallDisableNotify = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: UpdatesDisableNotify = 1
      To: UpdatesDisableNotify = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: AntiVirusOverride = 1
      To: AntiVirusOverride = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • From: FirewallOverride = 1
      To: FirewallOverride = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • From: EnableFirewall = 1
      To: EnableFirewall = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • From: DisableNotifications = 1
      To: DisableNotifications = 0

Step 6

Search and delete these files

[ 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%\{random}.tmp

Step 7

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