TROJ_ZACCES.SMQK
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It employs registry shell spawning by adding certain registry entries. This allows this malware to execute even when other applications are opened.
It modifies certain registry entries to disable Security Center functions. Doing this allows this malware to execute its routines without being detected. It modifies registry entries to disable the Windows Firewall settings. This action allows this malware to perform its routines without being deteted by the Windows Firewall.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
274,432 bytes
EXE
Yes
16 Jan 2012
Arrival Details
This Trojan 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 Trojan drops the following copies of itself into the affected system:
- %Application Data%\{random three letters}.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 drops the following files:
- %System Root%\Documents and Settings\All Users\Application Data\ags173q7g2p14omx43315rjvv
- %Application Data%\ags173q7g2p14omx43315rjvv
- %User Temp%\ags173q7g2p14omx43315rjvv
- %User Profile%\Templates\ags173q7g2p14omx43315rjvv
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %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 Trojan employs registry shell spawning to ensure its execution when certain file types are accessed by adding the following entries:
HKEY_CLASSES_ROOT\ah\shell\
open\command
{default} = ""%Application Data%\{random three letters}.exe" -a "%1" %*"
HKEY_CLASSES_ROOT\.exe\shell\
open\command
{default} = ""%Application Data%\{random three letters}.exe" -a "%1" %*"
HKEY_CURRENT_USER\Software\Classes\
.exe\shell\open\
command
{default} = ""%Application Data%\{random three letters}.exe" -a "%1" %*"
HKEY_CURRENT_USER\Software\Classes\
ah\shell\open\
command
{default} = ""%Application Data%\{random three letters}.exe" -a "%1" %*"
Other System Modifications
This Trojan modifies the following registry key(s)/entry(ies) as part of its installation routine:
HKEY_CLASSES_ROOT\.exe
{default} = "ah"
(Note: The default value data of the said registry entry is exefile.)
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\FIREFOX.EXE\shell\
open\command
{default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe""
(Note: The default value data of the said registry entry is %Program Files%\Mozilla Firefox\firefox.exe.)
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\FIREFOX.EXE\shell\
safemode\command
{default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"
(Note: The default value data of the said registry entry is "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode.)
HKEY_LOCAL_MACHINE\SOFTWARE\Clients\
StartMenuInternet\IEXPLORE.EXE\shell\
open\command
{default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Internet Explorer\iexplore.exe""
(Note: The default value data of the said registry entry is "%Program Files%\Internet Explorer\iexplore.exe".)
It adds the following registry keys as part of its installation routine:
HKEY_CLASSES_ROOT\ah
HKEY_CLASSES_ROOT\.exe\shell
HKEY_CLASSES_ROOT\.exe\shell\
runas
HKEY_CURRENT_USER\Software\Classes\
.exe
HKEY_CURRENT_USER\Software\Classes\
.exe\shell\runas
HKEY_CURRENT_USER\Software\Classes\
ah
HKEY_CURRENT_USER\Software\Classes\
ah\shell\runas
It modifies the following registry entries to disable Security Center functions:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"
(Note: The default value data of the said registry entry is 0.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"
(Note: The default value data of the said registry entry is 0.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"
(Note: The default value data of the said registry entry is 0.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = "1"
(Note: The default value data of the said registry entry is 0.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = "1"
(Note: The default value data of the said registry entry is 0.)
It modifies the following registry entries to disable the Windows Firewall settings:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = "1"
(Note: The default value data of the said registry entry is 0.)
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
EnableFirewall = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DoNotAllowExceptions = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile
DisableNotifications = "1"
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
- http://{BLOCKED}.com/1008000113
It deletes the initially executed copy of itself
SOLUTION
9.200
8.712.07
16 Jan 2012
8.713.00
17 Jan 2012
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
Identify and terminate files detected as TROJ_ZACCES.SMQK
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_CLASSES_ROOT
- ah
- ah
- In HKEY_CLASSES_ROOT\.exe
- shell
- shell
- In HKEY_CURRENT_USER\Software\Classes
- .exe
- .exe
- In HKEY_CURRENT_USER\Software\Classes
- ah
- ah
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
- DoNotAllowExceptions = "0"
- DoNotAllowExceptions = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile
- DisableNotifications = "1"
- DisableNotifications = "1"
Step 5
Delete these registry values
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_MACHINESOFTWAREMicrosoftSecurity Center
- FirewallDisableNotify = "1"
- UpdatesDisableNotify = "1"
- AntiVirusDisableNotify = "1"
- AntiVirusOverride = "1"
- FirewallOverride = "1"
- In HKEY_LOCAL_MACHINESOFTWAREPolicies
MicrosoftWindowsFirewallDomainProfile- EnableFirewall = "0"
- In HKEY_LOCAL_MACHINESOFTWAREPolicies
MicrosoftWindowsFirewall StandardProfile- EnableFirewall = "0"
- In HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoft
WindowsWindowsUpdate- DoNotAllowXPSP2 = "1"
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_CLASSES_ROOT\.exe
- From: {default} = "ah"
To: {default} = "exefile"
- From: {default} = "ah"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\shell\open\command
- From: {default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe""
To: {default} = "%Program Files%\Mozilla Firefox\firefox.exe"
- From: {default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe""
- In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\FIREFOX.EXE\shell\safemode\command
- From: {default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"
To: {default} = ""%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"
- From: {default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Mozilla Firefox\firefox.exe" -safe-mode"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\IEXPLORE.EXE\shell\open\command
- From: {default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Internet Explorer\iexplore.exe""
To: {default} = ""%Program Files%\Internet Explorer\iexplore.exe""
- From: {default} = ""%Application Data%\{random three letters}.exe" -a "%Program Files%\Internet Explorer\iexplore.exe""
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- From: EnableFirewall = "0"
To: EnableFirewall = "1"
- From: EnableFirewall = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
- From: DisableNotifications = "1"
To: DisableNotifications = "0"
- From: DisableNotifications = "1"
Step 7
Search and delete these files
- %System Root%\Documents and Settings\All Users\Application Data\ags173q7g2p14omx43315rjvv
- %Application Data%\ags173q7g2p14omx43315rjvv
- %User Temp%\ags173q7g2p14omx43315rjvv
- %User Profile%\Templates\ags173q7g2p14omx43315rjvv
Step 8
Scan your computer with your Trend Micro product to delete files detected as TROJ_ZACCES.SMQK. 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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