TSPY_ZBOT.YUYAEE
Trojan-Spy.Win32.Zbot.vnxz (Kaspersky); W32/Zbot.ACB!tr (Fortinet); Trojan winpe/ZBot.YSQZ (Norman)
Windows
Threat Type: Spyware
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
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.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
258,560 bytes
Yes
13 Jun 2015
Downloads files, Connects to URLs/IPs
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 1}\{random filename 1}.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 drops the following files:
- %Application Data%\{random folder 2}\{random filename 2}.tmp
- %Application Data%\{random folder 2}\{random filename 2}.{random extension}
- %User Temp%\tmp{random characters}.bat
- %Application Data%\Microsoft\Address Book\{username}.wab (for Windows XP and below)
(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.)
It creates the following folders:
- %Application Data%\{random folder 1}
- %Application Data%\{random folder 2}
(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 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 1}\{random filename 1}.exe "
Other System Modifications
This spyware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
WAB (for Windows XP and below)
HKEY_CURRENT_USER\Software\Microsoft\
{random key}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonBadCertRecving = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
EnableSPDY3_0 = "0"
HKEY_CURRENT_USER\Software\Microsoft\
{random key}
{random} = "{random values}"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkContactRefresh = "0" (for Windows XP and below)
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkFolderRefresh = "0" (for Windows XP and below)
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
FirstRun = "1" (for Windows XP and below)
It modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Lockdown_Zones\0
1609 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1406 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
1609 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\2
1609 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1406 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1609 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1A05 = "0"
(Note: The default value data of the said registry entry is "10500".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1A10 = "0"
(Note: The default value data of the said registry entry is "10500".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1406 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1609 = "0"
(Note: The default value data of the said registry entry is "1".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1A02 = "0"
(Note: The default value data of the said registry entry is "10500".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1A10 = "0"
(Note: The default value data of the said registry entry is "10500".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1A03 = "0"
(Note: The default value data of the said registry entry is "10500".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1A05 = "0"
(Note: The default value data of the said registry entry is "10500".)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
1A03 = "0"
(Note: The default value data of the said registry entry is "10500".)
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://{BLOCKED}e.su/chocotto.jpg
It deletes the initially executed copy of itself
SOLUTION
9.750
11.734.07
16 Jun 2015
11.735.00
17 Jun 2015
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 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 (for Windows XP and below)
- WAB (for Windows XP and below)
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_CURRENT_USER\Software\Microsoft\ Windows\CurrentVersion\Internet Settings
- WarnonBadCertRecving = "0"
- WarnonBadCertRecving = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\ Windows\CurrentVersion\Internet Settings
- EnableSPDY3_0 = "0"
- EnableSPDY3_0 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {GUID} = "%Application Data%\{random folder 1}\{random filename 1}.exe "
- {GUID} = "%Application Data%\{random folder 1}\{random filename 1}.exe "
Step 6
Restore this modified 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\Internet Settings\Lockdown_Zones\0
- From: 1609 = "0"
To: 1609 = "1"
- From: 1609 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
- From: 1406 = "0"
To: 1406 = "1"
- From: 1406 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
- From: 1609 = "0"
To: 1609 = "1"
- From: 1609 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\2
- From: 1609 = "0"
To: 1609 = "1"
- From: 1609 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- From: 1406 = "0"
To: 1406 = "1"
- From: 1406 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- From: 1406 = "0"
To: 1406 = "1"
- From: 1406 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- From: 1A05 = "0"
To: 1A05 = "10500"
- From: 1A05 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- From: 1A10 = "0"
To: 1A10 = "10500"
- From: 1A10 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1406 = "0"
To: 1406 = "1"
- From: 1406 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1406 = "0"
To: 1406 = "1"
- From: 1406 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1A02 = "0"
To: 1A02 = "10500"
- From: 1A02 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1A10 = "0"
To: 1A10 = "10500"
- From: 1A10 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1A03 = "0"
To: 1A03 = "10500"
- From: 1A03 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1A05 = "0"
To: 1A05 = "10500"
- From: 1A05 = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
- From: 1A03 = "0"
To: 1A03 = "10500"
- From: 1A03 = "0"
Step 7
Search and delete these files
- %User Temp%\tmp{random characters}.bat
- %Application Data%\Microsoft\Address Book\{username}.wab (for Windows XP and below)
Step 8
Reset Internet security settings
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.YUYAEE. 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 10
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\Microsoft\{random key}
- HKEY_CURRENT_USER\Software\Microsoft\{random key}
- {random} = {hex value}
- %Application Data%\{random folder 1}
- %Application Data%\{random folder 2}
- %Application Data%\{random folder 2}\{random filename 2}.tmp
- %Application Data%\{random folder 2}\{random filename 2}.{random extension}
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