TSPY_ZBOT.ZZZA
TrojanDownloader:Win32/Cutwail.BS (Microsoft); Backdoor.Trojan (Symantec); Trojan.Win32.Cutwail.cft (Kaspersky); Trojan horse Generic35.AWSS (AVG)
Windows 2000, Windows XP, Windows Server 2003
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
86,528 bytes
EXE
Yes
24 Apr 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:
- %User Profile%\ryxrezulmebc.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} 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
ryxrezulmebc = "%User Profile%\ryxrezulmebc.exe"
Other System Modifications
This spyware modifies the following file(s):
- %User Profile%\Application Data\Microsoft
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It adds the following registry keys:
HKEY_CURRENT_USER\Software\WinRAR
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
AppManagement = "{random values}"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
ryxrezulmebczap = "{random values}"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
2312304364 = "{random values}"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Tcpip\Parameters
MaxUserPort = "fffe"
HKEY_CURRENT_USER\Software\WinRAR
HWID = "{random values}"
Dropping Routine
This spyware drops the following files:
- %User Profile%\Microsoft\Crypto
- %User Profile%\Crypto\RSA
- %User Profile%\RSA\S-1-5-21-1645522239-1292428093-682003330-1003
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
This report is generated via an automated analysis system.
SOLUTION
9.300
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
Restart in Safe Mode
Step 3
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
- WinRAR
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
- ryxrezulmebc = "%User Profile%\ryxrezulmebc.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- AppManagement = "{random values}"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- ryxrezulmebczap = "{random values}"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- 2312304364 = "{random values}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters
- MaxUserPort = "fffe"
- In HKEY_CURRENT_USER\Software\WinRAR
- HWID = "{random values}"
Step 5
Search and delete these components
- %User Profile%\Microsoft\Crypto
- %User Profile%\Crypto\RSA
- %User Profile%\RSA\S-1-5-21-1645522239-1292428093-682003330-1003
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.ZZZA. 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
Restore deleted/modified files and/or registry entries from backup
*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %User Profile%\Application Data\Microsoft
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