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TROJ_KOVTER.THP

August 07, 2015
 ALIASES:

Trojan:Win32/Kovter!rfn (Microsoft); BackDoor-FCPD!CB76A618E8D2 (McAfee); Trojan.Gen (Symantec); Trojan-Downloader.Win32.Hyteod.apfe (Kaspersky); Mal/MSIL-NR (Sophos); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse MSIL7.BGQC (AVG)

 PLATFORM:

Windows

 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

315,450 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Aug 2015

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 creates the following folders:

  • %Application Data%\olut

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
olut = "%Application Data%\olut\olut.exe "

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_AJAX_CONNECTIONEVENTS

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41

HKEY_CURRENT_USER\Software\83E77C41

HKEY_LOCAL_MACHINE\SOFTWARE\30E35E96

HKEY_CURRENT_USER\Software\30E35E96

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Ratings
.Default = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
svchost.exe = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
explorer.exe = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
svchost.exe = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
explorer.exe = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_AJAX_CONNECTIONEVENTS
svchost.exe = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
1 = "%Application Data%\olut\olut.exe"

HKEY_CURRENT_USER\Software\83E77C41
1 = "%Application Data%\olut\olut.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
2 = "860"

HKEY_CURRENT_USER\Software\83E77C41
2 = "860"

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
3 = "33EA1857CDCD6310"

HKEY_CURRENT_USER\Software\83E77C41
3 = "33EA1857CDCD6310"

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
4 = "1436345435"

HKEY_CURRENT_USER\Software\83E77C41
4 = "1436345435"

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
7 = "30E35E96"

HKEY_CURRENT_USER\Software\83E77C41
7 = "30E35E96"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
olut = "%Application Data%\olut\olut.exe "

HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
5 = "{random characters}"

HKEY_CURRENT_USER\Software\83E77C41
5 = "{random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE
876A37E68E = "876A37E68E"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1400 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1402 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1407 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1206 = "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
2300 = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1809 = "3"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1400 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1402 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1407 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1206 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1601 = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
2300 = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1809 = "3"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\Safer\
CodeIdentifiers
TransparentEnabled = "1"

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

Dropping Routine

This Trojan drops the following files:

  • %Application Data%\olut\olut.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}ni.ru
  • {BLOCKED}.67.23
  • {BLOCKED}6.65.185
  • {BLOCKED}8.193.89
  • {BLOCKED}.3.109
  • {BLOCKED}7.225.33
  • {BLOCKED}.130.69
  • {BLOCKED}.140.157
  • {BLOCKED}6.254.112
  • {BLOCKED}3.112.130
  • {BLOCKED}.189.238
  • {BLOCKED}69.152
  • {BLOCKED}.115.183
  • {BLOCKED}.222.253
  • {BLOCKED}51.151
  • {BLOCKED}9.46.63
  • {BLOCKED}.255.118
  • {BLOCKED}23.131
  • {BLOCKED}.1.100
  • {BLOCKED}.108.206
  • {BLOCKED}.145.80
  • {BLOCKED}9.93.18
  • {BLOCKED}7.94.34
  • {BLOCKED}.133.83
  • {BLOCKED}.115.78
  • {BLOCKED}.253.112
  • {BLOCKED}.198.43
  • {BLOCKED}5.79.46
  • {BLOCKED}.119.94
  • {BLOCKED}2.128
  • {BLOCKED}.95.225
  • {BLOCKED}.113.135
  • {BLOCKED}.187.252
  • {BLOCKED}.160.76
  • {BLOCKED}.75.197
  • {BLOCKED}.131.187
  • {BLOCKED}.51.179
  • {BLOCKED}162.66
  • {BLOCKED}.37.26
  • {BLOCKED}.104.220
  • {BLOCKED}.124.251
  • {BLOCKED}3.38.51
  • {BLOCKED}8.15.27
  • {BLOCKED}.186.60
  • {BLOCKED}151.67
  • {BLOCKED}3.129.130
  • {BLOCKED}8.136.89
  • {BLOCKED}5.79.22
  • {BLOCKED}4.122.227
  • {BLOCKED}164.42
  • {BLOCKED}242.72
  • {BLOCKED}.209.228
  • {BLOCKED}.194.160
  • {BLOCKED}1.27.13
  • {BLOCKED}2.189.117
  • {BLOCKED}7.253.134
  • {BLOCKED}185.51
  • {BLOCKED}3.50.250
  • {BLOCKED}0.175.111
  • {BLOCKED}5.207.30
  • {BLOCKED}5.207.121
  • {BLOCKED}61.132
  • {BLOCKED}.19.161
  • {BLOCKED}8.30.20
  • {BLOCKED}.223.151
  • {BLOCKED}1.43.253
  • {BLOCKED}70.189
  • {BLOCKED}8.227.110
  • {BLOCKED}.73.129
  • {BLOCKED}6.175.7
  • {BLOCKED}.205.222
  • {BLOCKED}6.218.187
  • {BLOCKED}.91.137
  • {BLOCKED}.205.149
  • {BLOCKED}9.57.158
  • {BLOCKED}.220.183
  • {BLOCKED}7.64.28
  • {BLOCKED}4.21.183
  • {BLOCKED}.115.221
  • {BLOCKED}.122.215
  • {BLOCKED}.17.219
  • {BLOCKED}193.198
  • {BLOCKED}.24.22
  • {BLOCKED}2.244.196
  • {BLOCKED}.135.253
  • {BLOCKED}.18.10
  • {BLOCKED}190.168
  • {BLOCKED}3.176.115

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

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_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • FeatureControl
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl
    • FEATURE_BROWSER_EMULATION
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl
    • FEATURE_BROWSER_EMULATION
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl
    • FEATURE_AJAX_CONNECTIONEVENTS
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • 83E77C41
  • In HKEY_CURRENT_USER\Software
    • 83E77C41
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • 30E35E96
  • In HKEY_CURRENT_USER\Software
    • 30E35E96
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer
    • Run

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\Windows\CurrentVersion\Run
    • olut = "%Application Data%\olut\olut.exe "
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Ratings
    • .Default = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
    • svchost.exe = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
    • explorer.exe = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
    • svchost.exe = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
    • explorer.exe = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_AJAX_CONNECTIONEVENTS
    • svchost.exe = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
    • 1 = "%Application Data%\olut\olut.exe"
  • In HKEY_CURRENT_USER\Software\83E77C41
    • 1 = "%Application Data%\olut\olut.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
    • 2 = "860"
  • In HKEY_CURRENT_USER\Software\83E77C41
    • 2 = "860"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
    • 3 = "33EA1857CDCD6310"
  • In HKEY_CURRENT_USER\Software\83E77C41
    • 3 = "33EA1857CDCD6310"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
    • 4 = "1436345435"
  • In HKEY_CURRENT_USER\Software\83E77C41
    • 4 = "1436345435"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
    • 7 = "30E35E96"
  • In HKEY_CURRENT_USER\Software\83E77C41
    • 7 = "30E35E96"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • olut = "%Application Data%\olut\olut.exe "
  • In HKEY_LOCAL_MACHINE\SOFTWARE\83E77C41
    • 5 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\83E77C41
    • 5 = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • 876A37E68E = "876A37E68E"

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • 1400 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • 1402 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • 1407 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • From: 1206 = "0"
      To: 1206 = ""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: 2300 = "0"
      To: 2300 = ""1""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • 1809 = "3"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 1400 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 1402 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 1407 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 1206 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 1601 = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • From: 2300 = "0"
      To: 2300 = ""1""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • From: 1809 = "3"
      To: 1809 = ""3""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Safer\CodeIdentifiers
    • From: TransparentEnabled = "1"
      To: TransparentEnabled = ""1""

Step 6

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.
  • %Application Data%\olut\olut.exe

Step 7

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\olut

Step 8

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