TROJ_RANSOM.COO
Trojan:Win32/Malagent (Microsoft); Trojan.Gen (Symantec); Backdoor.SDBot (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.
It disables Task Manager, Registry Editor, and Folder Options.
TECHNICAL DETAILS
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 copies of itself into the affected system:
- %User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It creates the following folders:
- %User Profile%\Application Data\68AD0FD02ABF5
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
68AD0FD02ABF5 = "%User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
68AD0FD02ABF5 = "%User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
%User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe = "DisableNXShowUI"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers
%User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe = "DisableNXShowUI"
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\0
1400 = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1400 = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1400 = "0"
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\Explorer\
Advanced
HideIcons = "1"
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"
It deletes the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run\
68AD0FD02ABF5
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers\C:\Documents and Settings\
All Users\Application Data\68AD0FD02ABF5\
68AD0FD02ABF5.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run\
68AD0FD02ABF5
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\AppCompatFlags\
Layers\C:\Documents and Settings\
All Users\Application Data\68AD0FD02ABF5\
68AD0FD02ABF5.exe
Dropping Routine
This Trojan drops the following files:
- %User Startup%\Explorer.lnk
- %User Profile%\Application Data\twain.dll
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://xxx.{BLOCKED}0z.su/11/g.php
This report is generated via an automated analysis system.
SOLUTION
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
Enable Registry Editor, Task Manager, and Folder options
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.
- In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags
- Layers
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags
- Layers
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- System
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.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- 68AD0FD02ABF5 = "%User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- 68AD0FD02ABF5 = "%User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
- %User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe = "DisableNXShowUI"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
- %User Profile%\68AD0FD02ABF5\68AD0FD02ABF5.exe = "DisableNXShowUI"
Step 6
Restore this modified 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\0
- 1400 = "0"
- 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\3
- 1400 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- From: 1601 = "0"
To: 1601 = ""1""
- From: 1601 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- HideIcons = "1"
Step 7
Search and delete these files
- %User Startup%\Explorer.lnk
- %User Profile%\Application Data\twain.dll
Step 8
Search and delete this folder
- %User Profile%\Application Data\68AD0FD02ABF5
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_RANSOM.COO. 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 10
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- 68AD0FD02ABF5
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\C:\Documents and Settings\All Users\Application Data\68AD0FD02ABF5
- 68AD0FD02ABF5.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- 68AD0FD02ABF5
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers\C:\Documents and Settings\All Users\Application Data\68AD0FD02ABF5
- 68AD0FD02ABF5.exe
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