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TROJ_MORTO.AB

September 07, 2013
 Analysis by: Nikko Tamana
 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: No

  • 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 does not have any propagation routine.

It does not have any backdoor routine.

It does not have any information-stealing capability.

It requires its main component to successfully perform its intended routine.

  TECHNICAL DETAILS

File Size:

29,696 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Jul 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.

Other System Modifications

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
CertificateRevocation = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
DisableCachingOfSSLPages = "1"

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

HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
id2 = "{alphanumeric values}"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1001 = "3"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1201 = "0"

(Note: The default value data of the said registry entry is 3.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1601 = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1C00 = "0"

(Note: The default value data of the said registry entry is 10000.)

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Process Termination

This Trojan terminates processes or services that contain any of the following strings if found running in the affected system's memory:

  • 360rp
  • ACAAS
  • ArcaConfSV
  • AvastSvc
  • FPAVServer
  • FortiScand
  • GDFwSvc
  • K7RTScan
  • KVSrvXP
  • MPSvc
  • MsMpEng
  • NSESVC.EXE
  • PavFnSvr
  • RavMonD
  • SavService
  • SpySweeper
  • Vba32Ldr
  • a2service
  • avguard
  • avgwdsvc
  • avpmapp
  • ccSvcHst
  • cmdagent
  • coreServiceShell
  • freshclam
  • fsdfwd
  • knsdave
  • kxescore
  • mcshield
  • scanwscs
  • vsserv
  • zhudongfangyu

Information Theft

This Trojan does not have any information-stealing capability.

Other Details

This Trojan requires its main component to successfully perform its intended routine.

NOTES:
This Trojan connects to certain URL to download additional information and updated copy of itself.

It saves its downloaded file as {random}~MTMP{random}.EXE .

It can be executed by its main component using the following parameters:

[malware name] [URL] [port (optional)]

It drops unins.BAT to delete itself.

It deletes the following event logs:

  • Application log
  • Security log
  • System log

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.174.05

FIRST VSAPI PATTERN DATE:

25 Jul 2013

VSAPI OPR PATTERN File:

10.175.00

VSAPI OPR PATTERN Date:

26 Jul 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 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\Internet Settings
    • CertificateRevocation = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • DisableCachingOfSSLPages = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • NoFavoritesMenu = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\ODBC
    • id2 = "{alphanumeric values}"

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1001 = "3"
      To: 1001 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1201 = "0"
      To: 1201 = "3"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1601 = "0"
      To: 1601 = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1C00 = "0"
      To: 1C00 = "10000"

Step 5

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