BKDR_TZEEBOT.AG
TrojanSpy:MSIL/Tzeebot.A (Microsoft), a variant of MSIL/Spy.TzeeBot.B (ESET-NOD32), Trojan.Tzeebot (Symantec)
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.
It executes commands from a remote malicious user, effectively compromising the affected system.
It steals certain information from the system and/or the user.
However, as of this writing, the said sites are inaccessible.
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:
- %Application Data%\netscp.exe
- %Application Data%\{filename}.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.)
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%\Windows Media Player Tray.lnk
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Replace Files
- Copy Files
- Delete Files
- Upload Files
- Create and terminate processes
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- http://{BLOCKED}1.{BLOCKED}productupdate.com/DefaultWS.asmx
Dropping Routine
This backdoor drops the following files:
- %Application Data%\Microsoft\Windows\Last Items\AppID.guid
- %Application Data%\Microsoft\Windows\Last Items\{Year_month_day_hour_min_secs}k.tmp
- %User Temp%\{random 8 characters}.tmp
- %User Temp%\{random 8 characters}.0.cs
- %User Temp%\{random 8 characters}.dll
- %User Temp%\{random 8 characters}.cmdline
- %User Temp%\{random 8 characters}.out
- %User Temp%\{random 8 characters}.err
- %User Temp%\CSC10.tmp
- %User Temp%\RES11.tmp
(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.. %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.)
Information Theft
This backdoor steals the following information:
- User name
- Running Process
- IP address
- Keystroke logs
- OS Information
Stolen Information
This backdoor sends the data it gathers to the following email addresses via SMTP:
- {BLOCKED}cAnalyzer@yahoo.com
Other Details
However, as of this writing, the said sites are inaccessible.
NOTES:
The dropped files,added process and registries are dependent on the argument provided by the user.
It may accept any of the following arguments:
- /y
- /m
- /mr
- wmplayer.exe
- copy
- opensesemi
- /checkall
- /file1:
- /maxkf:
- /emailt:
- /nomail
- /dbg
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
Restart in Safe Mode
Step 4
Search and delete these files
- %Application Data%\Microsoft\Windows\Last Items\AppID.guid
- %Application Data%\Microsoft\Windows\Last Items\{Year_month_day_hour_min_secs}k.tmp
- %User Temp%\{random 8 characters}.tmp
- %User Temp%\{random 8 characters}.0.cs
- %User Temp%\{random 8 characters}.dll
- %User Temp%\{random 8 characters}.cmdline
- %User Temp%\{random 8 characters}.out
- %User Temp%\{random 8 characters}.err
- %User Temp%\CSC10.tmp
- %User Temp%\RES11.tmp
- %Application Data%\netscp.exe
- %Application Data%\{filename}.exe_
- %User Startup%\Windows Media Player Tray.lnk
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_TZEEBOT.AG. 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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