TROJ_DLOADER.ROS
PWS-LDPinch!ej (McAfee); Trojan.Gen (Symantec); ARC:SIM, [info]:Backdoor.NSIS.RA-based.a, PAK:[data1]:RadPack (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, Windows, XP, Windows Server 2003
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.
TECHNICAL DETAILS
787,423 bytes
EXE
Yes
29 Nov 2011
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:
- %User Temp%\$inst
(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.)
Autostart Technique
This Trojan registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
Other System Modifications
This Trojan deletes the following files:
- %User Temp%\$inst\0.tmp
- %User Temp%\$inst\1.tmp
- %User Temp%\$inst\2.tmp
- %User Temp%\$inst\3.tmp
- %User Temp%\$inst\4.tmp
- %User Temp%\$inst\5.tmp
- %User Temp%\$inst\6.tmp
- %User Temp%\$inst\7.tmp
- %User Temp%\$inst\8.tmp
- %User Temp%\$inst\9.tmp
- %User Temp%\$inst\10.tmp
- %User Temp%\$inst\11.tmp
- %User Temp%\$inst\12.tmp
- %System%\R_INST~1.BAT
(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.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
It deletes the following folders:
- %User Temp%\$inst\
(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.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\NtUsers
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\NtUsers
1 = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
NTAuthEnabled = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
Parameter = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
Port = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
Timeout = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
EnableLogFile = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
LogFilePath = "%System%\logfile.txt"
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
FilterIp = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
DisableTrayIcon = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
AutoAllow = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
AskUser = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\
v2.0\Server\Parameters
EnableEventLog = {random values}
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 1
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
4899:TCP = "4899:TCP:*:Enabled:systerm"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\r_server.exe = "%System%\r_server.exe:*:Enabled:systerm"
Dropping Routine
This Trojan drops the following files:
- %System%\r_server.exe
- %System%\r_install.bat
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
This report is generated via an automated analysis system.
SOLUTION
9.200
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Restart in Safe Mode
Step 3
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.
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts
- List
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server
- NtUsers
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server
- Parameters
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\SYSTEM\RAdmin\v2.0\Server\NtUsers
- 1={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- NTAuthEnabled={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- Parameter={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- Port={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- Timeout={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- EnableLogFile={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- LogFilePath="%System%\logfile.txt"
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- FilterIp={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- DisableTrayIcon={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- AutoAllow={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- AskUser={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\RAdmin\v2.0\Server\Parameters
- EnableEventLog={random values}
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- EnableFirewall=1
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- 4899:TCP="4899:TCP:*:Enabled:systerm"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %System%\r_server.exe="%System%\r_server.exe:*:Enabled:systerm"
Step 5
Search and delete this folder
Step 6
Search and delete these files
- %System%\r_server.exe
- %System%\r_install.bat
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOADER.ROS. 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
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %User Temp%\$inst\0.tmp
- %User Temp%\$inst\1.tmp
- %User Temp%\$inst\2.tmp
- %User Temp%\$inst\3.tmp
- %User Temp%\$inst\4.tmp
- %User Temp%\$inst\5.tmp
- %User Temp%\$inst\6.tmp
- %User Temp%\$inst\7.tmp
- %User Temp%\$inst\8.tmp
- %User Temp%\$inst\9.tmp
- %User Temp%\$inst\10.tmp
- %User Temp%\$inst\11.tmp
- %User Temp%\$inst\12.tmp
- %System%\R_INST~1.BAT
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