TROJ_OBVOD.HA

April 02, 2014
 Analysis by: Rika Joi Gregorio
 ALIASES:

TrojanDownloader:Win32/Obvod.N (Microsoft); Trojan-FBOH!D88D41B5D799 (McAfee); HEUR:Trojan.Win32.Generic (Kaspersky); Troj/Agent-ABNJ (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Generic32.CHCO (AVG)

 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: Yes

  • 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 uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

  TECHNICAL DETAILS

File Size:

156,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

31 Mar 2014

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:

  • %All Users Profile%\Application Data\{random file name}.exe

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It drops the following files:

  • %Windows%\Tasks\At1.job
  • %Windows%\Tasks\At2.job
  • %Windows%\Tasks\At3.job
  • %Windows%\Tasks\At4.job
  • %Windows%\Tasks\At5.job
  • %Windows%\Tasks\At6.job
  • %Windows%\Tasks\At7.job
  • %Windows%\Tasks\At8.job
  • %Windows%\Tasks\At9.job
  • %Windows%\Tasks\At10.job
  • %Windows%\Tasks\At11.job
  • %Windows%\Tasks\At12.job
  • %Windows%\Tasks\At13.job
  • %Windows%\Tasks\At14.job
  • %Windows%\Tasks\At15.job
  • %Windows%\Tasks\At16.job
  • %Windows%\Tasks\At17.job
  • %Windows%\Tasks\At18.job
  • %Windows%\Tasks\At19.job
  • %Windows%\Tasks\At20.job
  • %Windows%\Tasks\At21.job
  • %Windows%\Tasks\At22.job
  • %Windows%\Tasks\At23.job
  • %Windows%\Tasks\At24.job
  • %Windows%\Tasks\At25.job
  • %Windows%\Tasks\At26.job
  • %Windows%\Tasks\At27.job
  • %Windows%\Tasks\At28.job
  • %Windows%\Tasks\At29.job
  • %Windows%\Tasks\At30.job
  • %Windows%\Tasks\At31.job
  • %Windows%\Tasks\At32.job
  • %Windows%\Tasks\At33.job
  • %Windows%\Tasks\At34.job
  • %Windows%\Tasks\At35.job
  • %Windows%\Tasks\At36.job
  • %Windows%\Tasks\At37.job
  • %Windows%\Tasks\At38.job
  • %Windows%\Tasks\At39.job
  • %Windows%\Tasks\At40.job
  • %Windows%\Tasks\At41.job
  • %Windows%\Tasks\At42.job
  • %Windows%\Tasks\At43.job
  • %Windows%\Tasks\At44.job
  • %Windows%\Tasks\At45.job
  • %Windows%\Tasks\At46.job
  • %Windows%\Tasks\At47.job
  • %Windows%\Tasks\At48.job
  • %All Users Profile%\Application Data\5q2B8R.dat
  • %All Users Profile%\Application Data\{random file name}.exe.b
  • %All Users Profile%\Application Data\{random file name}.exe_.b

(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.)

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

Autostart Technique

The scheduled task executes the malware every:

  • hour

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
DisableScriptDebuggerIE = "yes"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Error Dlg Displayed On Every Error = "no"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
NoProtectedModeBanner = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\InternetSettings
WarnOnZoneCrossing = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\InternetSettings\
Zones\3
2500 = "3"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Direct3d
LA = "400"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
AtTaskMaxHours = "72"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.in
  • {BLOCKED}i.{BLOCKED}d.in
  • {BLOCKED}p.{BLOCKED}d.in
  • {BLOCKED}d.{BLOCKED}n

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.698.04

FIRST VSAPI PATTERN DATE:

31 Mar 2014

VSAPI OPR PATTERN File:

10.699.00

VSAPI OPR PATTERN Date:

01 Apr 2014

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

Scan your computer with your Trend Micro product and note files detected as TROJ_OBVOD.HA

Step 3

Terminate a process file/s detected as TROJ_OBVOD.HA

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • DisableScriptDebuggerIE = "yes"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Error Dlg Displayed On Every Error = "no"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • NoProtectedModeBanner = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\InternetSettings
    • WarnOnZoneCrossing = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\InternetSettings\Zones\3
    • 2500 = "3"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Direct3d
    • LA = "400"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • AtTaskMaxHours = "72"

Step 5

Search and delete this file

[ 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.
  • %Windows%\Tasks\At1.job
  • %Windows%\Tasks\At2.job
  • %Windows%\Tasks\At3.job
  • %Windows%\Tasks\At4.job
  • %Windows%\Tasks\At5.job
  • %Windows%\Tasks\At6.job
  • %Windows%\Tasks\At7.job
  • %Windows%\Tasks\At8.job
  • %Windows%\Tasks\At9.job
  • %Windows%\Tasks\At10.job
  • %Windows%\Tasks\At11.job
  • %Windows%\Tasks\At12.job
  • %Windows%\Tasks\At13.job
  • %Windows%\Tasks\At14.job
  • %Windows%\Tasks\At15.job
  • %Windows%\Tasks\At16.job
  • %Windows%\Tasks\At17.job
  • %Windows%\Tasks\At18.job
  • %Windows%\Tasks\At19.job
  • %Windows%\Tasks\At20.job
  • %Windows%\Tasks\At21.job
  • %Windows%\Tasks\At22.job
  • %Windows%\Tasks\At23.job
  • %Windows%\Tasks\At24.job
  • %Windows%\Tasks\At25.job
  • %Windows%\Tasks\At26.job
  • %Windows%\Tasks\At27.job
  • %Windows%\Tasks\At28.job
  • %Windows%\Tasks\At29.job
  • %Windows%\Tasks\At30.job
  • %Windows%\Tasks\At31.job
  • %Windows%\Tasks\At32.job
  • %Windows%\Tasks\At33.job
  • %Windows%\Tasks\At34.job
  • %Windows%\Tasks\At35.job
  • %Windows%\Tasks\At36.job
  • %Windows%\Tasks\At37.job
  • %Windows%\Tasks\At38.job
  • %Windows%\Tasks\At39.job
  • %Windows%\Tasks\At40.job
  • %Windows%\Tasks\At41.job
  • %Windows%\Tasks\At42.job
  • %Windows%\Tasks\At43.job
  • %Windows%\Tasks\At44.job
  • %Windows%\Tasks\At45.job
  • %Windows%\Tasks\At46.job
  • %Windows%\Tasks\At47.job
  • %Windows%\Tasks\At48.job
  • %All Users Profile%\Application Data\5q2B8R.dat
  • %All Users Profile%\Application Data\{random file name}.exe.b
  • %All Users Profile%\Application Data\{random file name}.exe_.b

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_OBVOD.HA. 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.


Did this description help? Tell us how we did.