TROJ_DNSCHANG.XT

This Trojan has received attention from independent media sources and/or other security firms.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

During the testing of this Trojan, the IP addresses set as the DNS servers are the following:

• Preferred DNS server: {BLOCKED}.{BLOCKED}.97.20

• Alternate DNS Server: {BLOCKED}.{BLOCKED}.97.21

As a result, Internet activities on the affected sytem can be monitored by a remote malicious user.

This Trojan may be downloaded from remote sites by other malware.

Arrival Details

This Trojan may be downloaded from remote site(s) by the following malware:

• TROJ_PIDIEF.AAL

It may be downloaded from the following remote sites:

• http://{BLOCKED}.{BLOCKED}.175.29/load.php

Installation

This Trojan drops the following copies of itself into the affected system:

• %Program Files%\Common Files\{random file name}.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
DnsUpdater = %Program Files%\Common Files\{malware file name}.exe

Other Details

This Trojan adds the following registry entries to add an uninstall option to the Control Panel:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1\if1
(Default) = {ethernet adapter}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1
UninstallString = %Program Files%\Common Files\{malware file name}.exe uninstall

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1
DisplayName = DNS Changer (remove only)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1
Size =

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1
NoModify = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1
NoRepair = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1\if1
DhcpEnabled = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1\if1
DnsRecords = {hex values}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
DnsUpdater1
DnsFile = {BLOCKED}.{BLOCKED}.97.20 {BLOCKED}.{BLOCKED}.97.21

Based on analysis of the codes, it has the following capabilities:

• Connects to this URL to get IP addresses that it sets as the new DNS server address: http://www.{BLOCKED}ckin.com/inlogger.php?h={computer name}&u={user name}&t={execution time}
• Connects to this URL for succeeding executions to check for new IP addresses that it sets as the new DNS server address: http://www.{BLOCKED}ckin.com/dns_update.php

It connects to the following possibly malicious URL:

• http://www.{BLOCKED}ckin.com/inlogger.php?h={computer name}&u={user name}&t={execution time}
• http://www.{BLOCKED}ckin.com/dns_update.php