Worm.Win32.CHESTBD.A
Trojan:Win32/Occamy.C (Microsoft) ; HEUR:Trojan-Dropper.Win32.Generic (Kaspersky)
Windows
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
This Worm 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
976,384 bytes
EXE
No
10 Oct 2018
Drops files
Arrival Details
This Worm 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 Worm drops the following files:
- %Application Data%\Xå8+Ö -> Detected as Trojan.Win32.CHESTBD.A
- %Application Data%\Xå8+Ö.zip - Deleted Afterwards
- %System%\dllcache\sethc.exe -> Detected as Trojan.Win32.CHESTBD.A
- %System%\sethc.exe -> Detected as Trojan.Win32.CHESTBD.A
(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, 7, and 8.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It drops the following copies of itself into the affected system:
- {Drive C to Z}:\Gato.jpg .exe
- %Application Data%\{malware file name}.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, 7, and 8.)
Autostart Technique
This Worm drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\Gato.lnk -> Target file: %Application Data%\{malware file name}.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, 7, and 8.)
Other Details
This Worm does the following:
- It propagates on drives (From C:\ to Z:\) present on the infected machine when the drive is either being Inserted into or Ejected from the infected machine.
SOLUTION
9.850
14.568.02
16 Oct 2018
14.569.00
17 Oct 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
Identify and terminate files detected as Worm.Win32.CHESTBD.A
- 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 4
Search and delete this file
- {Drive C to Z}:\Gato.jpg .exe
- %System%\dllcache\sethc.exe
- %System%\sethc.exe
- %Application Data%\{malware file name}.exe
- %Application Data%\Xå8+Ö
- %Application Data%\Xå8+Ö.zip
- %User Startup%\Gato.lnk
Step 5
Scan your computer with your Trend Micro product to delete files detected as Worm.Win32.CHESTBD.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 the following Trend Micro Support pages for more information:
Did this description help? Tell us how we did.