BKDR_ANDROM.JBR
Generic Downloader.z (McAfee), Trojan.Win32.VBKrypt.prxx (Kaspersky), Backdoor.Trojan (Symantec)
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: Yes
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
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.
It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.
TECHNICAL DETAILS
81,920 bytes
EXE
Yes
22 Mar 2013
Compromises system security
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:
- {All Users Profile}\{random}.exe
- {All Users Profile}\svchost.exe (when running in virtual machine)
- %ProgramData%\{random}.exe (Windows Vista and higher versions)
- %ProgramData%\svchost.exe (Windows Vista and higher versions and running in virtual machine)
(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).)
It injects threads into the following normal process(es):
- svchost.exe
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\Policies\
Explorer\Run
{random number} = "%ProgramData%\{random}.exe" (Windows Vista and higher versions)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
{random number} = "{All Users Profile}\{random}.exe" (Versions lower than Windows Vista)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "%ProgramData%\svchost.exe" (Windows Vista and higher versions, running in virtual machine and Java update is disabled in startup)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "{All Users Profile}\svchost.exe" (Versions lower than Windows Vista, running in virtual machine and Java update is disabled in startup)
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 higher versions, running in virtual machine and 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 Users Profile}\svchost.exe" (Versions lower than Windows Vista, running in virtual machine and 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 location}\{malware filename} = "{malware location}\{malware filename}:*:Enabled:Unrepentingness detenebrate ophthalmoplegias luracan"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\svchost.exe = "%System%\svchost.exe:*:Generic Host Process"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\msiexec.exe = "%System%\msiexec.exe:*:Generic Host Process"
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Download a file from C&C server and save it as %User Temp%\{random number}.exe
- Download a file from C&C server and save it as %System Root%\Documents and Settings\All Users\ms{random number}.dat and loads it
- Start a process
- Uninstall itself
- Remote command prompt
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It connects to the following websites to send and receive information:
- http://www.{BLOCKED}53535.com/www/gate.php
NOTES:
It checks if it is being run in VMWare environment or Emulation software. If it is being run in a VMWare environment or Emulation software, it performs another routine where it opens port 8000 and listen for a backdoor command for performing remote shell execution.
It also checks if there is a running network monitoring software in the affected machine. If found, it also performs its other routine.
SOLUTION
9.300
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 BKDR_ANDROM.JBR
Step 3
Restart in Safe Mode
Step 4
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\Policies\Explorer\Run
- {random number} = "%ProgramData%\{random}.exe" (Windows Vista and higher versions)
- {random number} = "%ProgramData%\{random}.exe" (Windows Vista and higher versions)
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- {random number} = "{All Users Profile}\{random}.exe" (Versions lower than Windows Vista)
- {random number} = "{All Users Profile}\{random}.exe" (Versions lower than Windows Vista)
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- SunJavaUpdateSched = "%ProgramData%\svchost.exe" (Windows Vista and higher versions, running in virtual machine and Java update is disabled in startup)
- SunJavaUpdateSched = "%ProgramData%\svchost.exe" (Windows Vista and higher versions, running in virtual machine and Java update is disabled in startup)
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- SunJavaUpdateSched = "{All Users Profile}\svchost.exe" (Versions lower than Windows Vista, running in virtual machine and Java update is disabled in startup)
- SunJavaUpdateSched = "{All Users Profile}\svchost.exe" (Versions lower than Windows Vista, running in virtual machine and Java update is disabled in startup)
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %System%\svchost.exe = "%System%\svchost.exe:*:Generic Host Process"
- %System%\svchost.exe = "%System%\svchost.exe:*:Generic Host Process"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\authorizedapplications\list
- %System%\msiexec.exe = "%System%\msiexec.exe:*:Generic Host Process"
- %System%\msiexec.exe = "%System%\msiexec.exe:*:Generic Host Process"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- {malware location}\{malware filename} = "{malware location}\{malware filename}:*:Enabled:Unrepentingness detenebrate ophthalmoplegias luracan"
- {malware location}\{malware filename} = "{malware location}\{malware filename}:*:Enabled:Unrepentingness detenebrate ophthalmoplegias luracan"
Step 5
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" (Windows Vista and higher versions, running in virtual machine and Java update is enabled in startup)
To: SunJavaUpdateSched = "{Java Installation Folder}\jusched.exe"
- From: SunJavaUpdateSched = "%ProgramData%\svchost.exe" (Windows Vista and higher versions, running in virtual machine and Java update is enabled in startup)
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- From: SunJavaUpdateSched = "{All Users Profile}\svchost.exe" (Versions lower than Windows Vista, running in virtual machine and Java update is enabled in startup)
To: SunJavaUpdateSched = "{Java Installation Folder}\jusched.exe"
- From: SunJavaUpdateSched = "{All Users Profile}\svchost.exe" (Versions lower than Windows Vista, running in virtual machine and Java update is enabled in startup)
Step 6
Search and delete these files
- %User Temp%\{random number}.exe
- %System Root%\Documents and Settings\All Users\ms{random number}.dat
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ANDROM.JBR. 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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