BKDR64_TDSS.JS
Windows XP (64-bit), Windows Vista (64-bit), Windows 7 (64-bit)

Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
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 lowers the security setting of Internet Explorer.
TECHNICAL DETAILS
53,248 bytes
EXE
Yes
11 Nov 2013
Connects to URLs/IPs, Compromises system security
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 component file(s):
- "%User Temp%\{random folder name}\{random folder name}\wow.dll" - detected as BKDR64_TDSS.JS
(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It drops the following non-malicious file:
- "%User Temp%\{random folder name}\{random folder name}\wow.ini"
(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
It creates the following folders:
- %User Temp%\{random folder name}\{random folder name}
(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)
Autostart Technique
This backdoor modifies the following registry entry(ies) to enable its automatic execution at every system startup:
HKEY_CLASSES_ROOT\CLSID\{fbeb8a05-beee-4442-804e-409d6c4515e9}\
InProcServer32
[Default] = "%User Temp%\{random folder name}\{random folder name}\wow.dll"
(Note: The default value data of the said registry entry is "%System%\SHELL32.dll.)
Other System Modifications
This backdoor adds the following registry entries:
HKEY_CURRENT_USER\Software\Classes\
clsid\{fbeb8a05-beee-4442-804e-409d6c4515e9}\inprocserver32
[Default] = "%User Temp%\{random folder name}\{random folder name}\wow.dll"
Web Browser Home Page and Search Page Modification
This backdoor lowers the security setting of Internet Explorer.
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}r.com
- {BLOCKED}k.com
- {BLOCKED}e.com
- {BLOCKED}z.com
- {BLOCKED}.{BLOCKED}.232.20
SOLUTION
9.300
10.404.08
11 Nov 2013
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 delete files detected as BKDR64_TDSS.JS using either the Startup Disk or Recovery Console
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\Classes\clsid\{fbeb8a05-beee-4442-804e-409d6c4515e9}\inprocserver32
- [Default] = "%User Temp%\{random folder name}\{random folder name}\wow.dll"
- [Default] = "%User Temp%\{random folder name}\{random folder name}\wow.dll"
Step 4
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_CLASSES_ROOT\CLSID\{fbeb8a05-beee-4442-804e-409d6c4515e9}\InProcServer32
- From: [Default] = "%User Temp%\{random folder name }\{random folder name}\wow.dll"
To: [Default] = "%System%\SHELL32.dll"
- From: [Default] = "%User Temp%\{random folder name }\{random folder name}\wow.dll"
Step 5
Reset Internet security settings
Step 6
Search and delete these folders
- %User Temp%\{random folder name}\{random folder name}
Step 7
Scan your computer with your Trend Micro product to delete files detected as BKDR64_TDSS.JS. 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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