BKDR_ANDROM.YJN
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted:
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.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
101,442,688 bytes
EXE
Yes
21 Feb 2017
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 drops the following files:
- %User Temp%\cdo{random number}.dll
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It drops the following copies of itself into the affected system:
- %All Users Profile%\ms{random}.exe
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
{Random Numbers} = "%All Users Profile%\ms{random}.exe"
Other System Modifications
This backdoor adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
Load = ""
HKEY_CURRENT_USER\Software\Microsoft\
Windows
{Random Numbers} = "{Encrypted Data}"
HKEY_CURRENT_USER\Keyboard Layout
1 = "{Encrypted Data}"
HKEY_CURRENT_USER\Keyboard Layout
2 = "{Encrypted Data}"
Other Details
This backdoor connects to the following possibly malicious URL:
- http://{BLOCKED}erstatus.ru/order.php
- http://flux.{BLOCKED}79.ru/test
- http://{BLOCKED}.{BLOCKED}.82.50/disfigure
However, as of this writing, the said sites are inaccessible.
SOLUTION
9.850
13.254.05
03 Mar 2017
13.255.80
04 Mar 2017
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
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\CurrentVersion\Policies\Explorer\Run
- {Random Numbers} = "%All Users Profile%\ms{random}.exe"
- {Random Numbers} = "%All Users Profile%\ms{random}.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- Hidden = "2"
- Hidden = "2"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- ShowSuperHidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- Load = ""
- Load = ""
- In HKEY_CURRENT_USER\Software\Microsoft\Windows
- {Random Numbers} = "{Encrypted Data}"
- {Random Numbers} = "{Encrypted Data}"
- In HKEY_CURRENT_USER\Keyboard Layout
- 1 = "{Encrypted Data}"
- 1 = "{Encrypted Data}"
- In HKEY_CURRENT_USER\Keyboard Layout
- 2 = "{Encrypted Data}"
- 2 = "{Encrypted Data}"
Step 5
Search and delete this file
- %User Temp%\cdo{random number}.dll
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ANDROM.YJN. 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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