Backdoor.Win32.COBEACON.OSLJAI
Gen:Variant.Bulz.1217(BITDEFENDER); BScope.Trojan.Swrort (VBA32)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
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 executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
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 adds the following processes:
- cmd.exe /c set KCBDaOagLE=6566 & reg add HKCU\SOFTWARE\mfSHHuXxjQrzxcR /v plTQxPKiomXOVqV /t REG_DWORD /d 5868 & exit
Other System Modifications
This Backdoor adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\SOFTWARE\mfSHHuXxjQrzxcR
plTQxPKiomXOVqV = 5868
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Manage Files (Create, Delete, Modify, List files in Directory, Copy Files, Move Files)
- Manage Directory (Create, Set path)
- Read/Modify file time
- Manage Services (Create, Delete, Start)
- Impersonate Tokens
- Open Processes and obtain process information
- Inject Code to Processes
- Adjust permissions in process
- Connect to a named pipe
- Retrieve IP Address mapping table
- Create, Terminate, and List Running Processes
- List Drive Information
- Enumerate Registry Data
- Executes arbitrary code
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- http://{BLOCKED}.{BLOCKED}.194.115/pixel.gif
Information Theft
This Backdoor gathers the following data:
- User Name
- Computer Name
- Host Name
- Local IP Address
- OS Version and Architecture
- Current Process ID
Other Details
This Backdoor does the following:
- It connects to the following URL to download an encrypted DLL component which it will load in its memory:
- http://{BLOCKED}.{BLOCKED}.194.115/E4lw
- It adds the following environment variable and value:
- KCBDaOagLE= 6566
SOLUTION
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
- Troj.Win32.TRX.XXPE50FFF038
Step 2
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 3
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 4
Restart in Safe Mode
Step 5
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_CURRENT_USER\SOFTWARE\mfSHHuXxjQrzxcR
- plTQxPKiomXOVqV = 5868
- plTQxPKiomXOVqV = 5868
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.COBEACON.OSLJAI. 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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