TROJ_FOLER.A
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted: No
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 employs registry shell spawning by adding certain registry entries. This allows this malware to execute even when other applications are opened.
As of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
102400 bytes
EXE
No
25 Jan 2016
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 a copy of itself in the following folders using different file names:
- C:\WINDOWS\uninstall.exe
It drops and executes the following files:
- C:\WINDOWS\copy.bat
Autostart Technique
This Trojan employs registry shell spawning to ensure its execution when certain file types are accessed by adding the following entries:
HKCU\Software\Microsoft\
Windows\CurrentVersion\Explorer\
FileExts\.exe
Application = uninstall.exe
Other System Modifications
This Trojan adds the following registry entries:
HKLM\SOFTWARE\Microsoft\
ielook
"" = 00-00-00-00-00-00
HKLM\SOFTWARE\Classes\
Applications\uninstall.exe\shell\
open\command
"" = "C:\WINDOWS\uninstall.exe "%1" %*"
Dropping Routine
This Trojan drops the following files:
- C:\WINDOWS\qr.txt
- C:\WINDOWS\up.vbe
- C:\Program Files\userpic\qr.TXT
- C:\Program Files\userpic\qr.VBE
- C:\Program Files\userpic\qr.bat
Download Routine
This Trojan downloads the file from the following URL and renames the file when stored in the affected system:
- http://{BLOCKED}5.{BLOCKED}3.com/tj.asp?time=20160101160935&mac=00-00-00-00-00-00&username=blog_folder&content=99,qokW_fn[gB&/&*%62W,PWNCV-NHXD%1+4&tGL 2931 tGF0/.-@TOCS*85.,4i)GS(_qnC)L'l_smI%0*,0*,/0,0*,0*,/0%dlnlQdfn`h=
- http://{BLOCKED}4.{BLOCKED}i.net/soft/001.jpg
It saves the files it downloads using the following names:
- C:\WINDOWS\tm.tmp
- C:\Program Files\userpic\sogoupyupdate.exe
As of this writing, the said sites are inaccessible.
SOLUTION
9.800
12.296.06
25 Jan 2016
12.297.00
25 Jan 2016
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
Restore this modified registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.exe
- Application = uninstall.exe
- Application = uninstall.exe
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_LOCAL_MACHINE\SOFTWARE\Microsoft\ielook
- = 00-00-00-00-00-00
- = 00-00-00-00-00-00
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Applications\uninstall.exe\shell\open\command
- = "C:\WINDOWS\uninstall.exe "%1" %*"
- = "C:\WINDOWS\uninstall.exe "%1" %*"
Step 5
Remove malware/grayware files dropped/downloaded by TROJ_FOLER.A. (Note: Please skip this step if the threats listed below have already been removed.)
- C:\WINDOWS\copy.bat
- C:\WINDOWS\qr.txt
- C:\WINDOWS\up.vbe
- C:\Program Files\userpic\qr.TXT
- C:\Program Files\userpic\qr.VBE
- C:\Program Files\userpic\qr.bat
- C:\WINDOWS\tm.tmp
- C:\Program Files\userpic\sogoupyupdate.exe
Step 6
Scan your computer with your Trend Micro product to delete files detected as TROJ_FOLER.A. 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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