Backdoor.Win32.NANOCORE.DDL
Windows
![](/vinfo/imgFiles/legend.jpg)
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.
TECHNICAL DETAILS
1,173,504 bytes
EXE
Yes
05 Nov 2019
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 copies of itself into the affected system:
- %User Profile%\BthRadioMedia\advapi32res.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).)
It creates the following folders:
- %User Profile%\BthRadioMedia
- %Application Data%\remcos
(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).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
Autostart Technique
This Backdoor drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\BthRadioMedia.url
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)
Other System Modifications
This Backdoor deletes the following files:
- %Application Data%\Mozilla\Firefox\Profiles\lj5mikyj.default\key3.db
- %Application Data%\Mozilla\Firefox\Profiles\lj5mikyj.default\logins.json
- %Application Data%\Mozilla\Firefox\Profiles\lj5mikyj.default\cookies.sqlite
(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\Remcos-ZZQUAF
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Remcos-ZZQUAF
exepath = "{random characters}"
HKEY_CURRENT_USER\Software\Remcos-ZZQUAF
licence = "278F8A3F3CEAF86E793DC52B1083EB91"
HKEY_CURRENT_USER\Software\Remcos-ZZQUAF
FR = "1"
Dropping Routine
This Backdoor drops the following files:
- %Application Data%\remcos\logs.dat
- %User Profile%\BthRadioMedia\BthRadioMedia.vbs
(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %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).)
Other Details
This Backdoor connects to the following possibly malicious URL:
- http://newlogs.{BLOCKED}o.org
This report is generated via an automated analysis system.
SOLUTION
9.850
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
Restart in Safe Mode
Step 3
Delete this registry key
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
- Remcos-ZZQUAF
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_CURRENT_USER\Software\Remcos-ZZQUAF
- exepath = "{random characters}"
- In HKEY_CURRENT_USER\Software\Remcos-ZZQUAF
- licence = "278F8A3F3CEAF86E793DC52B1083EB91"
- In HKEY_CURRENT_USER\Software\Remcos-ZZQUAF
- FR = "1"
Step 5
Search and delete these components
- %Application Data%\remcos\logs.dat
- %User Profile%\BthRadioMedia\BthRadioMedia.vbs
Step 6
Search and delete these folders
- %User Profile%\BthRadioMedia
- %Application Data%\remcos
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Backdoor.Win32.NANOCORE.DDL. 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.
Step 8
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Application Data%\Mozilla\Firefox\Profiles\lj5mikyj.default\key3.db
- %Application Data%\Mozilla\Firefox\Profiles\lj5mikyj.default\logins.json
- %Application Data%\Mozilla\Firefox\Profiles\lj5mikyj.default\cookies.sqlite
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