BKDR_NOANCOOE.THAOCAI
HEUR:Trojan.Win32.Generic (Kaspersky)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
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.
It gathers certain information on the affected computer.
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 drops the following copies of itself into the affected system:
- %Program Files%\{String1}\{String2}.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), 7 (32-bit), and 8 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), 7 (64-bit), and 8 (64-bit).)
It adds the following processes:
- tross.sfx.exe -p126 -d%temp%
It creates the following folders:
- %Application Data%\{GUID}
- %Application Data%\{GUID}\Logs
- %Application Data%\{GUID}\Logs\{user name}
- %Program Files%\{String1}{String2}
(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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), 7 (32-bit), and 8 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), 7 (64-bit), and 8 (64-bit).)
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\Run
{String1}{String3} = %Program Files%\{String1}{String3}\{String1}{String2}.exe
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Manage its backdoor file:
- Update itself
- Restart connection
- Disconnect
- Terminate itself
- Uninstall itself
- System Control:
- Restart machine
- Shutdown machine
- Lock machine
- Browse files and folders
- Task Manager
- Edit registry
- Remote console (Command Prompt)
- Remote execute a file
- Remote execute a script (Batch, HTML, VBS, Python, Java, PHP)
- Remote control the machine
- Remote control mouse
- Recover browser passwords
- Log Keystrokes
- View the screen/webcam
- Listen to audio/microphone
- Send Messages / Chat with the malicious user
- Swap/Unswap mouse buttons
- Open/Close CD/DVD Tray
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}ra.hopto.org:4722
- {BLOCKED}n.ddns.net:4722
Dropping Routine
This Backdoor drops the following files:
- %Application Data%\{GUID}\catalog.dat
- %Application Data%\{GUID}\run.dat
- %Application Data%\{GUID}\settings.bin
- %Application Data%\{GUID}\Logs\{user name}\KB_{Random numbers}.dat
(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.)
Information Theft
This Backdoor gathers the following information on the affected computer:
- Computer Name
- User Name
- CPU Usage
- Available and Free Memory
- Active Window Title
- Operating System Version
- System Type (32-bit or 64-bit)
- Malware Filename
- Installed Anti-Virus/Anti-Spyware
Other Details
This Backdoor does the following:
- String1:
- dhcp
- upnp
- tcp
- udp
- saas
- iss
- smtp
- dos
- dpi
- pci
- scsi
- wan
- lan
- nat
- imap
- nas
- ntfs
- wpa
- dsl
- agp
- arp
- ddp
- dns
- String2:
- ss
- mon
- Mgr
- sv
- svc
- host
- String3:
- Subsystem
- Monitor
- Manager
- Service
- Host
- The SFX file contains the following:
- fdd.bat -> contains the password of tross.sfx.exe, executed to extract tross.sfx.exe
- tross.sfx.exe
SOLUTION
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 delete files detected as BKDR_NOANCOOE.THAOCAI using either the Startup Disk or Recovery Console
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\Run
- {String1}{String3} = %Program Files%\{String1}{String3}\{String1}{String2}.exe
- {String1}{String3} = %Program Files%\{String1}{String3}\{String1}{String2}.exe
Step 5
Search and delete these folders
- %Application Data%\{GUID}
- %Program Files%\{String1}{String2}
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NOANCOOE.THAOCAI. 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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