TSPY_ZBOT.YUNA
PWS:Win32/Zbot.gen!GO(Microsoft),Trojan-Spy.Win32.Zbot.rtcz(Kaspersky),Win32/Spy.Zbot.AAU trojan(NOD32)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 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.
TECHNICAL DETAILS
421,888 bytes
EXE
Yes
17 Mar 2014
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 copies of itself into the affected system:
- %Application Data%\{random folder name 1}\{random filename 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%\Microsoft\Address Book
(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
{random} = "%Application Data%\{random folder name 1}\{random filename 1}.exe"
Other System Modifications
This spyware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
HKEY_CURRENT_USER\Software\Microsoft\
WAB
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key}
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key}
DisplayName = "{malware file name}.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key}
ErrorControl = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key}
ImagePath = "\??\%System%\drivers\{random file name 2}.sys"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key}
Start = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random key}
Type = "1"
HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random} = "{random values}"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkContactRefresh = "0"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkFolderRefresh = "0"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
{Default} = "%Application Data%\Microsoft\Address Book\{username}.wab"
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{port1}:UDP = "{port1}:UDP:*:Enabled:UDP {port1}"
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{port2}:TCP = "{port2}:TCP:*:Enabled:TCP {port2}"
Dropping Routine
This spyware drops the following files:
- %Application Data%\Microsoft\Address Book\{username}.wab
- %System%\drivers\{random file name 2}.sys - malicious
(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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)
Other Details
This spyware connects to the following possibly malicious URL:
- {random generated URLS}
SOLUTION
9.700
10.670.02
17 Mar 2014
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
Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.YUNA
Step 3
Identify and delete files detected as TSPY_ZBOT.YUNA using either the Startup Disk or Recovery Console
Step 4
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\Microsoft
- WAB
- WAB
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- {random key}
- {random key}
Step 5
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\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
- %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- {port1}:UDP = "{port1}:UDP:*:Enabled:UDP {port1}"
- {port1}:UDP = "{port1}:UDP:*:Enabled:UDP {port1}"
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- {port2}:TCP = "{port2}:TCP:*:Enabled:TCP {port2}"
- {port2}:TCP = "{port2}:TCP:*:Enabled:TCP {port2}"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random} ="%Application Data%\{random folder name 1}\{random filename 1}.exe}"
- {random} ="%Application Data%\{random folder name 1}\{random filename 1}.exe}"
Step 6
Search and delete these folders
- %Application Data%\{random folder name 1}
- %Application Data%\Microsoft\Address Book
Step 7
Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.YUNA. 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
The following created registry key(s) 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 keys with a backup of the system registry. Note that the said key(s) do not have to be deleted since it won't be harmful to the system:
- In HKEY_CURRENT_USER\Software\Microsoft
- {random}
- {random}
NOTES:
Identify the following file to be deleted on Step 3:
- %System%\drivers\{random file name 2}.sys
Identify the following registry which is used by its dropped file:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random key}
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