BKDR_ZBAL.B
PWS:Win32/Zbal.B (Microsoft); Win32/PSW.Papras.DP (ESET-NOD32), Backdoor.Win32.Matsnu.bm (Kaspersky),
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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 does not have any propagation routine.
It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
594,432 bytes
EXE
Yes
28 May 2015
Connects to URLs/IPs, Steals information
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 file(s)/component(s):
- %Application Data%\{GUID}\{random 1}.dat
- %Application Data%\{GUID}\{random 2}.dat
- %Application Data%\{GUID}\{random 3}.dat
- %Application Data%\{GUID}\{random 4}.dat
- %Application Data%\{GUID}\{random 5}.dat
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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:
- %Application Data%\{GUID}\{random}.exe
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 adds the following processes:
- svchost.exe
It creates the following folders:
- %Application Data%\{GUID}
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 injects codes into the following process(es):
- explorer.exe
- Added svchost.exe
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{GUID} = "%Application Data%\{GUID}\{random}.exe"
Propagation
This backdoor does not have any propagation routine.
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Enumerate Process
- Create\Terminate Process
- Download and execute\load arbitrary files
- Create\Delete Directory
- Update Itself
- Unintall itself
- Update Config
- Block and Unblock URL
- Grab FTP, Cookies, Certificates,POP
- Upload Information
- Perform Remote Control
- Add, Delete, or Edit Registry
- Create, Open, or Edit File
- Execute file
It connects to the following websites to send and receive information:
- http://{BLOCKED}id.com/adminta/forum.php
- http://{BLOCKED}ox.com/adminta/forum.php
- http://{BLOCKED}odfm.com/adminta/forum.php
- http://{BLOCKED}m.com/adminta/forum.php
Information Theft
This backdoor gathers the following data:
- Disk Serial Number
- Host's Name
- Default Language
Other Details
This backdoor connects to the following URL(s) to check for an Internet connection:
- Microsoft.com
It deletes the initially executed copy of itself
NOTES:
It does not have rootkit capabilities.
It does not exploit any vulnerability.
SOLUTION
9.750
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {GUID} = "%Application Data%\{GUID}\{random}.exe"
- {GUID} = "%Application Data%\{GUID}\{random}.exe"
Step 5
Search and delete these folders
- %Application Data%\{GUID}
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZBAL.B. 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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