TROJ_KOVTER.AUSJD
Trojan.Win32.Poweliks.pbo(Kaspersky);Mal/Kovter-Z(Sophos);Trojan:Win32/Kovter!rfn(Microsoft);Win32/Kovter.I trojan(Eset Nod32)
Windows

Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
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 modifies the Internet Explorer Zone Settings.
It connects to certain websites to send and receive information. It deletes itself after execution.
TECHNICAL DETAILS
371,512 bytes
EXE
Yes
14 Feb 2017
Connects to URLs/IPs, Creates files
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 files:
- %AppDataLocal%\{Random String}\{Random String}.{Random Extension} - Encrypted file
- %AppDataLocal%\{Random String}\{Random}.bat - Starts Encrypted file
- %AppDataLocal%\{Random String}\{Random String}.exe -> Slightly modified Copy
(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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.)
It adds the following processes:
- %System%\regsvr32.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It creates the following folders:
- %AppDataLocal%\{Random String}
(Note: %AppDataLocal% is the Application Data folder found in Local Settings, where it is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local 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.)
It injects codes into the following process(es):
- %System%\regsvr32.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
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
(Default) = %AppDataLocal%\{Random String}\{Random String}.exe
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
(Default) = %AppDataLocal%\{Random String}\{Random String}.exe
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
(Default) = %AppDataLocal%\{Random String}\{Random String}.bat
HKEY_CURRENT_USER\Software\Classes\
{Random String}\shell\open\
command
(Default) = "%System%\mshta.exe" "javascript:{Random}="{Random}";{Random Variable}=new ActiveXObject("WScript.Shell");{Random}="{Random}";EKb5F=Rq55.RegRead("HKCU\software\{Random String 2}\{Random Value Name}");{Random}="{Random}";eval({Random Variable});{Random}="{Random}";"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\{Random String 1}
HKEY_CURRENT_USER\Software\{Random String 2}
HKEY_LOCAL_MACHINE\Software\{Random String 2}
HKEY_CURRENT_USER\Software\Classes\
.{Random Extension}
HKEY_CURRENT_USER\Software\Classes\
{Random String}
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate
DisableOSUpgrade = 1
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\WindowsUpdate\
OSUpgrade
ReservationsAllowed = 0
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
iexplore.exe = 8888
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
regsvr.exe = 8888
HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
iexplore.exe = 8888
HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Main\FeatureControl\
FEATURE_BROWSER_EMULATION
regsvr.exe = 8888
HKEY_LOCAL_MACHINE\SOFTWARE\{Random String 2}
{Random Value Name 1} = {Encrypted Data}
HKEY_LOCAL_MACHINE\SOFTWARE\{Random String 2}
{Random Value Name 2} = {Random Characters}
HKEY_LOCAL_MACHINE\SOFTWARE\{Random String 2}
{Random Value Name 3} = {Random Characters}
HKEY_LOCAL_MACHINE\SOFTWARE\{Random String 2}
{Random Value Name 4} = {Random Characters}
HKEY_LOCAL_MACHINE\SOFTWARE\{Random String 2}
{Random Value Name 5} = {Random Characters}
HKEY_LOCAL_MACHINE\SOFTWARE\{Random String 2}
{Random Value Name 6} = {Random Characters}
HKEY_CURRENT_USER\SOFTWARE\{Random String 2}
{Random Value Name 1} = {Encrypted Data}
HKEY_CURRENT_USER\SOFTWARE\{Random String 2}
{Random Value Name 2} = {Random Characters}
HKEY_CURRENT_USER\SOFTWARE\{Random String 2}
{Random Value Name 3} = {Random Characters}
HKEY_CURRENT_USER\SOFTWARE\{Random String 2}
{Random Value Name 4} = {Random Characters}
HKEY_CURRENT_USER\SOFTWARE\{Random String 2}
{Random Value Name 5} = {Random Characters}
HKEY_CURRENT_USER\SOFTWARE\{Random String 2}
{Random Value Name 6} = {Random Characters}
Web Browser Home Page and Search Page Modification
This Trojan modifies the Internet Explorer Zone Settings.
Other Details
This Trojan connects to the following website to send and receive information:
- http://{BLOCKED}.{BLOCKED}.72.90/upload.php
- {Random Generated IP Address} - used for click-fraud activity
It does the following:
- It may download and install the following software on the affected system:
- Microsoft .Net Framework
- Microsoft Powershell
- Adobe Flash Player
- Connects to certain IP address for its click-fraud activity.
- Uses power shell to execute the obfuscated javascript codes in the registry.
It deletes itself after execution.
SOLUTION
9.850
13.220.04
14 Feb 2017
13.221.00
15 Feb 2017
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Restart in Safe Mode
Step 4
Delete this registry key
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.
- HKEY_CURRENT_USER\Software\{Random String 1}
- HKEY_CURRENT_USER\Software\{Random String 2}
- HKEY_LOCAL_MACHINE\Software\{Random String 2}
- HKEY_CURRENT_USER\Software\Classes\.{Random Extension}
- HKEY_CURRENT_USER\Software\Classes\{Random String}
Step 5
Delete this registry value
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.
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- (Default) = %AppDataLocal%\{Random String}\{Random String}.bat
- HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- (Default) = %AppDataLocal%\{Random String}\{Random String}.exe
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
- (Default) = %AppDataLocal%\{Random String}\{Random String}.exe
- HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
- DisableOSUpgrade = 1
- HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\OSUpgrade
- ReservationsAllowed = 0
- HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
- iexplore.exe = 8888
- HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
- regsvr.exe = 8888
- HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
- iexplore.exe = 8888
- HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_BROWSER_EMULATION
- regsvr.exe = 8888
Step 6
Search and delete these folders
- %AppDataLocal%\{Random String}
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_KOVTER.AUSJD. 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.
Step 8
Reset Internet security settings
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