Analysis by: Abraham Latimer Camba
 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 employs registry shell spawning by adding certain registry entries. This allows this malware to execute even when other applications are opened.

  TECHNICAL DETAILS

File Size: 356,352 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 02 Mar 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 drops the following copies of itself into the affected system and executes them:

  • C:\Documents and Settings\All Users\Application Data\{random hex string}\{random hex string}.exe

Autostart Technique

This Trojan employs registry shell spawning to ensure its execution when certain file types are accessed by adding the following entries:

HKEY_CLASSES_ROOT\.exe
(Default) = "{first 5 characters of malware filename}"

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

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}
(Default) = "Application"

HKEY_CLASSES_ROOT\%s
(Default) = "{first 5 characters of malware filename}"

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}
Content Type = "application/x-msdownload"

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
open\command
IsolatedCommand = "%1" %*

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
runas\command
(Default) = "C:\Documents and Settings\All Users\Application Data\{random hex string}\{random hex string}.exe" -s "%1" %*

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
open\command
(Default) = "C:\Documents and Settings\All Users\Application Data\{random hex string}\{random hex string}.exe" -s "%1" %*

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
start\command
(Default) = "%1" %*

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
runas\command
IsolatedCommand = "%1" %*

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
start\command
IsolatedCommand = "%1" %*

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\svc
FirewallOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\svc
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\svc
UpdatesDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\svc
AntiVirusDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\svc
AntiVirusOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = "1"

HKEY_CLASSES_ROOT\%s

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\DefaultIcon

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\DefaultIcon
(Default) = "%1"

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
open

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
open\command

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
runas

HKEY_CLASSES_ROOT\{random value}\shell\
runas\command

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
start

HKEY_CLASSES_ROOT\{first 5 characters of malware filename}\shell\
start\command

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\svc

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.812.02
FIRST VSAPI PATTERN DATE: 02 Mar 2012
VSAPI OPR PATTERN File: 8.813.00
VSAPI OPR PATTERN Date: 03 Mar 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Since this malware uses rootkit technology, detection and removal using normal and safe mode methods may not eliminate it completely. This procedure restarts the system using the Windows Recovery Console.

  1. Insert the Windows Installation CD into the CD drive, then Press the restart button.
  2. Upon prompt, press any key to boot from the CD.
  3. On the main menu, type r to go to the Recovery Console.
  4. Type the drive that contains Windows (usually C:) and press Enter.
  5. In the input box, type the following then press Enter:
    SET AllowAllPaths = TRUE
    DEL "%System Root%\Documents and Settings\All Users\Application Data\{random hex string}\{random hex string}.exe"
  6. Type exit and press Enter to restart the system normally.

Step 3

Restore this modified 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_CLASSES_ROOT\.exe
    • From: (Default) = "{first 5 characters of malware filename}"
      To: (Default) = "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\SOFTWARE\Microsoft\Security Center
    • FirewallOverride = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • FirewallDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UpdatesDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • AntiVirusDisableNotify = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • AntiVirusOverride = "1"

Step 5

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
    • %s
  • In HKEY_CLASSES_ROOT
    • {first 5 characters of malware filename}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • svc

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.KPP. 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.

NOTES:

Perform these actions before step 3:

  1. Click Start > Run, type %Windows%, then press Enter.
  2. Locate Regedit.exe, select it and press CTRL+C then CTRL+V to copy and paste it.
  3. Locate Copy of Regedit.exe and rename it to Regedit.com
  4. Double-click Regedit.com.


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