Analysis by: Jimelle Monteser
ALIASES:

Troj/FKVBatCh-A (Sophos Lite), BAT/KillAV.JT (exact) (FPROT), Trojan.BAT.KillAV.po (Kaspersky), Rogue:Win32/Winwebsec (Microsoft), FakeAlert-SecurityTool!bat (NAI), BAT/KillAV.MC (Panda)

 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:
 INFORMATION EXPOSURE:

  • 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 arrives as a component bundled with malware/grayware packages.

  TECHNICAL DETAILS

File Size: 2,001 bytes
File Type: BAT
Initial Samples Received Date: 30 Sep 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.

It arrives as a component bundled with malware/grayware packages.

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Security Center\Svc

It adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = "0"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\policies\
system
EnableVirtualization = "0"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\SystemRestore
RPSessionInterval = "0"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
AS2014 = "%All Users Profile%\Application Data\{random folder name}\{random filename}.exe"

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\Svc
FirewallDisableNotify = "1"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Security Center\Svc
FirewallOverride = "1"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Security Center\Svc
UpdatesDisableNotify = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\wscsvc
Start = "4"

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

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\wuauserv
Start = "4"

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

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
AntiVirusOverride = "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 Cente
FirewallOverride = "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.)

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 10.310.10
FIRST VSAPI PATTERN DATE: 01 Oct 2013
VSAPI OPR PATTERN File: 10.311.00
VSAPI OPR PATTERN Date: 01 Oct 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

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\Security Center
    • Svc

Step 3

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\policies\system
    • EnableLUA = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\policies\system
    • EnableVirtualization = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\SystemRestore
    • RPSessionInterval = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • AS2014 = "%All Users Profile%\Application Data\{random folder name}\{random filename}.exe"

Step 4

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_LOCAL_MACHINE\System\CurrentControlSet\Services\wscsvc
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\wuauserv
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Security Center
    • From: AntiVirusDisableNotify = "1"
      To: AntiVirusDisableNotify = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Security Center
    • From: AntiVirusOverride = "1"
      To: AntiVirusOverride = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Security Center
    • From: FirewallDisableNotify = "1"
      To: FirewallDisableNotify = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Security Center
    • From: FirewallOverride = "1"
      To: FirewallOverride = "0"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Security Center
    • From: UpdatesDisableNotify = "1"
      To: UpdatesDisableNotify = "0"

Step 5

Scan your computer with your Trend Micro product to delete files detected as BAT_KILLAV.AXY. 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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