BKDR_BANDOK.SM
TrojanProxy:Win32/Dosenjo.A (Microsoft), Backdoor.Win32.Bandok.it (Kaspersky), Trojan.Adclicker (Symantec), W32/Bandok.IT!tr.bdr (Fortinet), W32/BackdoorX.ARIV (Fprot), Backdoor.Win32.Bandok (Ikarus),
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
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.
As of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
67,072 bytes
EXE
Yes
30 Oct 2010
Downloads files
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 Root%\Documents and Settings\All Users\Application Data\csrss.exe
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It drops the following non-malicious file:
- %System Root%\Documents and Settings\All Users\Application Data\loggy.txt
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- BabloPobejdaetZlo2
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Svchost = "%System Root%\Documents and Settings\All Users\Application Data\csrss.exe"
Other System Modifications
This backdoor adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
SvchostID = "{machine ID converted}"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
SvchostVersion = "{number}"
HKEY_USERS\.DEFAULT\SOFTWARE\
Microsoft\Windows\CurrentVersion
SvchostVersion = "{number}"
It adds the following registry keys as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Servers
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPOrts\
List
110:TCP = "110:TCP:*:Enabled:svchost"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System Root%\Documents and Settings\All Users\Application Data\csrss.exe = "%System Root%\Documents and Settings\All Users\Application Data\csrss:*:Enabled:svchost"
Download Routine
This backdoor connects to the following URL(s) to download its component file(s):
- http://{BLOCKED}lero.com/s.html?cachingDeny={random characters}&id={converted machine ID}
- http://{BLOCKED}stats.ru/s.html?cachingDeny={random characters}&id={converted machine ID}
- http://{BLOCKED}tats.ru/s.html?cachingDeny={random characters}&id={converted machine ID}
- http://{BLOCKED}ler.com/s.html?cachingDeny={random characters}&id={converted machine ID}
- http://{BLOCKED}-ana1itics.com/s.html?cachingDeny={random characters}&id={converted machine ID}
- http://{BLOCKED}machiner.com/s.html?cachingDeny={random characters}&id={converted machine ID}
It saves the files it downloads using the following names:
- %User Temp%\csrss5.dll
- %System%\csrss5.dll
(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.)
As of this writing, the said sites are inaccessible.
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
Identify and terminate files detected as BKDR_BANDOK.SM
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- Servers
- Servers
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Svchost = "%System Root%\Documents and Settings\All Users\Application Data\csrss.exe"
- Svchost = "%System Root%\Documents and Settings\All Users\Application Data\csrss.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- SvchostID = "{machine ID converted}"
- SvchostID = "{machine ID converted}"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- SvchostVersion = "{number}"
- SvchostVersion = "{number}"
- In HKEY_USERS\.DEFAULT\SOFTWARE\Microsoft\Windows\CurrentVersion
- SvchostVersion = "{number}"
- SvchostVersion = "{number}"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %System Root%\Documents and Settings\All Users\Application Data\csrss.exe = "%System Root%\Documents and Settings\All Users\Application Data\csrss:*:Enabled:svchost"
- %System Root%\Documents and Settings\All Users\Application Data\csrss.exe = "%System Root%\Documents and Settings\All Users\Application Data\csrss:*:Enabled:svchost"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPOrts\List
- 110:TCP = "110:TCP:*:Enabled:svchost"
- 110:TCP = "110:TCP:*:Enabled:svchost"
Step 5
Search and delete these files
Step 6
Scan your computer with your Trend Micro product to delete files detected as BKDR_BANDOK.SM. 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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