BKDR_XTRAT.AO
Trojan.Win32.Generic.pak!cobra (Sunbelt)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
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.
It deletes itself after execution.
TECHNICAL DETAILS
368,640 bytes
EXE
Yes
06 Nov 2012
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:
- %System%\winn\win.exe
(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.)
It creates the following folders:
- %System%\winn
(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.)
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
HKLG = "%System%\winn\win.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
HKLG = "%System%\winn\win.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{5460C4DF-B266-909E-CB58-E32B79832EB2}
StubPath = "%System%\winn\win.exe restart"
Other System Modifications
This backdoor deletes the following files:
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.1808.329406
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.1808.329421
- %User Profile%\v2.0.50727.42\security.config.cch.1808.329593
- %User Profile%\Windows\fC6gZF7.xtr
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.1296.370250
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.1296.370250
- %User Profile%\v2.0.50727.42\security.config.cch.1296.370359
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %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 adds the following registry keys:
HKEY_CURRENT_USER\SOFTWARE\fC6gZF7
HKEY_LOCAL_MACHINE\Software\Microsoft\
Active Setup\Installed Components\{5460C4DF-B266-909E-CB58-E32B79832EB2}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\fC6gZF7
ServerStarted = "11/5/2012 9:05:50 AM"
HKEY_CURRENT_USER\Software\fC6gZF7
InstalledServer = "%System%\winn\win.exe"
Dropping Routine
This backdoor drops the following files:
- %User Profile%\Windows\fC6gZF7.cfg
(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.)
Other Details
This backdoor connects to the following possibly malicious URL:
- http://kdiksnns.{BLOCKED}o.org:334/1234567890.functions
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
9.300
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_CURRENT_USER\SOFTWARE
- fC6gZF7
- In HKEY_LOCAL_MACHINE\Software\Microsoft\Active Setup\Installed Components
- {5460C4DF-B266-909E-CB58-E32B79832EB2}
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\Run
- HKLG = "%System%\winn\win.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HKLG = "%System%\winn\win.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{5460C4DF-B266-909E-CB58-E32B79832EB2}
- StubPath = "%System%\winn\win.exe restart"
- In HKEY_CURRENT_USER\Software\fC6gZF7
- ServerStarted = "11/5/2012 9:05:50 AM"
- In HKEY_CURRENT_USER\Software\fC6gZF7
- InstalledServer = "%System%\winn\win.exe"
Step 5
Search and delete this file
- %User Profile%\Windows\fC6gZF7.cfg
Step 6
Search and delete this folder
- %System%\winn
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_XTRAT.AO. 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.
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.1808.329406
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.1808.329421
- %User Profile%\v2.0.50727.42\security.config.cch.1808.329593
- %User Profile%\Windows\fC6gZF7.xtr
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\security.config.cch.1296.370250
- %Windows%\Microsoft.NET\Framework\v2.0.50727\config\enterprisesec.config.cch.1296.370250
- %User Profile%\v2.0.50727.42\security.config.cch.1296.370359
Did this description help? Tell us how we did.