Worm.Win32.RIMECUD.I
Trojan:Win32/Rimecud.A (MICROSOFT)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware, Propagates via removable drives
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.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
130,889 bytes
EXE
Yes
15 Jun 2023
Compromises system security, Steals information, Connects to URLs/IPs, Modifies system registry, Deletes 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 copies of itself into the affected system:
- %User Profile%\kohwe.exe → attributes are set to READONLY, HIDDEN, and SYSTEM
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following processes:
- %System%\svchost.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- `=08+10
It injects itself into the following processes as part of its memory residency routine:
- svchost.exe → executed by the malware
Autostart Technique
This Worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = %User Profile%\kohwe.exe
Other System Modifications
This Worm deletes the following files:
- %User Profile%\kohwe.exe → if the executed file path and name is not "%User Profile%\kohwe.exe"
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Propagation
This Worm creates the following folders in all removable drives:
- torpide
It drops the following copy(ies) of itself in all removable drives:
- {Removable Drive}\torpide\gengems.exe
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
[autorun]
;garbage characters
shell\open\command=torpide\gengems.exe
;garbage characters
action=Open folder to view files using Windows Explorer
;garbage characters
Shell\Open\Command=torpide\gengems.exe
;garbage characters
shellexecute=torpide\gengems.exe
;garbage characters
shell\explore\command=torpide\gengems.exe
;garbage characters
icon=SHELL32.dll,4
;garbage characters
open=torpide\gengems.exe
;garbage characters
USEAUTOPLAY=1
;garbage characters
Backdoor Routine
This Worm executes the following commands from a remote malicious user:
- Update / Remove self
- Download and execute arbitrary files
- USB Spreader
- Visit a URL / Display pop-up advertisements
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- udp://{BLOCKED}trule.com:11111
- udp://{BLOCKED}esask.net:11111
- udp://{BLOCKED}gesonest.com:11111
- udp://{BLOCKED}ince.kz:11111
- udp://{BLOCKED}lks.su:11111
Information Theft
This Worm gathers the following data:
- IP Address
- Network Setting
- Operation System
- Admin Rights
- Country
- Port Used
- Username / Hostname
SOLUTION
9.200
18.524.03
22 Jun 2023
18.525.00
23 Jun 2023
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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
Restart in Safe Mode
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\Windows NT\CurrentVersion\Winlogon
- Taskman = "%User Profile%\kohwe.exe"
- Taskman = "%User Profile%\kohwe.exe"
Step 5
Search and delete AUTORUN.INF files created by Worm.Win32.RIMECUD.I that contain these strings
- [autorun]
- ;garbage characters
- shell\open\command=torpide\gengems.exe
- ;garbage characters
- action=Open folder to view files using Windows Explorer
- ;garbage characters
- Shell\Open\Command=torpide\gengems.exe
- ;garbage characters
- shellexecute=torpide\gengems.exe
- ;garbage characters
- shell\explore\command=torpide\gengems.exe
- ;garbage characters
- icon=SHELL32.dll,4
- ;garbage characters
- open=torpide\gengems.exe
- ;garbage characters
- USEAUTOPLAY=1
- ;garbage characters
Step 6
Search and delete this file
- %User Profile%\kohwe.exe
- {Removable Drive}:\torpide\gengems.exe
Step 7
Search and delete these folders
- {Removable Drive}:\torpide
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.RIMECUD.I. 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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