BKDR_ANDROM.LSK
Worm:Win32/Gamarue (Microsoft), Trojan-Spy.Zbot (Ikarus), Win32/TrojanDownloader.Wauchos.K trojan (Nod32)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
98,304 bytes
EXE
Yes
07 Aug 2013
Arrival Details
This backdoor 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 backdoor drops the following copies of itself into the affected system:
- %ProgramData%\svchost.exe (Windows Vista and 7 only)
- %All Users Profile%\svchost.exe
- %All Users Profile%\{Random File Name}.exe
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).. %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.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "%ProgramData%\svchost.exe" (Windows Vista and 7 only and if Java update is disabled in startup)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "{All User's Profile}\svchost.exe" (versions other than Windows Vista and 7 and if Java update is disabled in startup)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
{random number} = "%All User's Temp%\{Random File Name}.exe"
It modifies the following registry entry(ies) to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "%ProgramData%\svchost.exe" (Windows Vista and 7 only and if Java update is enabled in startup)
(Note: The default value data of the said registry entry is {Java Installation Folder}\jusched.exe.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "{All User's Profile}\svchost.exe" (versions other than Windows Vista and 7 and if Java update is enabled in startup)
(Note: The default value data of the said registry entry is {Java Installation Folder}\jusched.exe.)
Other System Modifications
This backdoor creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path}\{malware name}.exe = "{malware path}\{malware name}.exe:*:Enabled:Pidgin Portable"
SOLUTION
9.700
10.204.06
09 Aug 2013
10.205.00
09 Aug 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
Step 3
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.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- SunJavaUpdateSched = "%ProgramData%\svchost.exe"
- SunJavaUpdateSched = "%ProgramData%\svchost.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- SunJavaUpdateSched = "{All User's Profile}\svchost.exe"
- SunJavaUpdateSched = "{All User's Profile}\svchost.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- {random number} = "%All User's Temp%\{Random File Name}.exe"
- {random number} = "%All User's Temp%\{Random File Name}.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- {malware path}\{malware name}.exe = "{malware path}\{malware name}.exe:*:Enabled:Pidgin Portable"
- {malware path}\{malware name}.exe = "{malware path}\{malware name}.exe:*:Enabled:Pidgin Portable"
Step 4
Restore these modified registry values
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- From: SunJavaUpdateSched = "%ProgramData%\svchost.exe"
To: SunJavaUpdateSched = "{Java Installation Folder}\jusched.exe"
- From: SunJavaUpdateSched = "%ProgramData%\svchost.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- From: SunJavaUpdateSched = "{All User's Profile}\svchost.exe"
To: SunJavaUpdateSched = "{Java Installation Folder}\jusched.exe"
- From: SunJavaUpdateSched = "{All User's Profile}\svchost.exe"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ANDROM.LSK. 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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