BKDR_YAKES.AUSDF
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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.
It connects to a website to send and receive information.
It takes advantage of certain vulnerabilities.
TECHNICAL DETAILS
86,016 bytes
EXE
No
07 Aug 2015
Connects to URLs/IPs
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 file(s)/component(s):
- %Windows%\Tasks\winsvr.dll - uses parameters install and exe
- %User Temp%\stdole2.tlb - detected as BKDR_YAKES.AUSDF
- %User Temp%\cmd.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\run
explorer = "rundll32 %Windows%\tasks\winsvr.dll,exe"
Backdoor Routine
This backdoor connects to the following websites to send and receive information:
- http://webstore.{BLOCKED}o.org/js/write.asp?action={action}&mac={mac address}
IP: {BLOCKED}.{BLOCKED}.126.58 - http://webstore.{BLOCKED}o.org/js/get_command.asp?mac={mac address}&temp={random numbers}
IP: {BLOCKED}.{BLOCKED}.126.58
Other Details
This backdoor does the following:
- It uses dog as User Agent.
It takes advantage of the following vulnerabilities:
SOLUTION
9.800
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
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer
- run
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\run
- explorer = rundll32 %Windows%\tasks\winsvr.dll,exe
Step 4
Search and delete these files
- %User Temp%\cmd.exe
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_YAKES.AUSDF. 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 6
Download and apply this security patch Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors. Microsoft Security Bulletin MS13-053
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