BKDR_DEMTRANC.AI
Trojan:Win32/Demtranc.C (Microsoft), BackDoor-EKF (McAfee), a variant of Win32/Demtranc.AA trojan (Eset), Trojan.Gen (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:
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.
TECHNICAL DETAILS
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 adds the following folders:
- %Application Data%\Help
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
It drops the following file(s)/component(s):
- %Application Data%\Help\iexplore.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
Autostart Technique
This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
iexplore = "%Application Data%\Help\iexplore.exe"
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}.{BLOCKED}h.com/SUS{value}O{value}.jsp?{value}
- {BLOCKED}.{BLOCKED}h.com/DES{value}O{value}.jsp?{value}
- {BLOCKED}s.{BLOCKED}h.com/AES{value}O{value}.jsp?{value}
- {BLOCKED}s.{BLOCKED}h.com/PES{value}O{value}.jsp?{value}
- {BLOCKED}s.{BLOCKED}h.com/ZES{value}O{value}.jsp?{value}
- {BLOCKED}s.{BLOCKED}h.com/SEU{value}O{value}.jsp?{value}
SOLUTION
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
Identify and terminate files detected as BKDR_DEMTRANC.AI
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- 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 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
- iexplore = "%Application Data%\Help\iexplore.exe"
- iexplore = "%Application Data%\Help\iexplore.exe"
Step 4
Search and delete this folder
- %Application Data%\Help
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_DEMTRANC.AI. 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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