TSPY_ZBOT.AAFS
PWS:Win32/Zbot.AJB (Microsoft); Trojan.Zbot (Malwarebytes); Trojan-Spy.Win32.Zbot.qysj (Kaspersky); Trojan-Spy.Win32.Zbot (Ikarus); TrojanSpy.Zbot.r5 (CAT-QuickHeal)
Windows 2000, Windows XP (32-bit and 64-bit), Windows Server 2003, Windows Vista (32-bit and 64-bit), Windows 7 (32-bit and 64-bit)
Threat Type: Spyware
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It modifies the Internet Explorer Zone Settings.
However, as of this writing, the said sites are inaccessible. It deletes the initially executed copy of itself.
TECHNICAL DETAILS
251,128 bytes
EXE
Yes
23 Dec 2013
Arrival Details
This spyware 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 spyware drops the following files:
- %Application Data%\{random folder name 2}\{random file name 2}.{random file extension}
- %Application Data%\{random folder name 1}\{random file name 1}.exe
(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 and 7.)
It creates the following folders:
- %Application Data%\{random folder name 1}
- %Application Data%\{random folder name 2}
(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 and 7.)
Autostart Technique
This spyware 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%\{random folder name 1}\{random file name 1}.exe"
Other System Modifications
This spyware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random string} = "{random hex values}"
Web Browser Home Page and Search Page Modification
This spyware modifies the Internet Explorer Zone Settings.
Other Details
This spyware connects to the following possibly malicious URL:
- http://www.google.com/{BLOCKED}p
- http://{BLOCKED}ydd300.com
However, as of this writing, the said sites are inaccessible.
It deletes the initially executed copy of itself
SOLUTION
9.300
10.490.02
23 Dec 2013
10.491.00
23 Dec 2013
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
- {random file name 1}.exe = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
- {random file name 1}.exe = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
Step 5
Reset Internet security settings
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.AAFS. 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 7
The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.
- HKEY_CURRENT_USER\Software\{random}
- %Application Data%\{random folder name 1}
- %Application Data%\{random folder name 2}
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