| 1.Impact:
Possible theft of data and control of the targeted machine
leading to a
compromise of all resources the machine is connected to. This
Trojan
also has the ability to delete data, steal passwords and disable
the
machine. Other versions are capable of launching DDoS attacks.
2.Detailed Information:
This Trojan affects the following operating systems:
Windows 95
Windows 98
Windows ME
Windows NT
Windows 2000
Windows XP
No other systems are affected. This is a windows exceutable that
makes
changes to the system registry, Win.ini and System.ini. When
first
executed the Trojan replicates itself and in most cases, gives
the copy
a random name. This Trojan may use the file extensions ".exe" or
".dll".
Subseven is an improved version of the Netbus Trojan (see sids
114,
115), Subseven DEFCON8 2.1 is an improved version of Subseven
that
affects Windows 95 and 98 implementations.
The Trojan changes system startup files and registry settings to
add the
Subseven sever to programs normally started on boot.
3.Attack Scenarios:
This Trojan may be delivered to the target in a number of
ways. This
event is indicative of an existing infection being activated.
Initial
compromise can be in the form of a Win32 installation program
that may
use the extension ".jpg" or ".bmp" when delivered via e-mail for
example.
4.Ease of Attack:
This is Trojan activity, the target machine may already be
compromised.
Updated virus definition files are essential in detecting this
Trojan.
5.Corrective Action:
This is a particularly difficult Trojan to remove and should
only be
attempted by an experienced Windows Administrator.
Edit the system registry to remove the extra keys or restore a
previously known good copy of the registry.
Affected registry keys are:
HKEY_CLASSES_ROOT\exefile\shell\open\command
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current
Version\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\RunServices
HKEY_LOCAL_MACHINE\Hardware\Data
HKEY_LOCAL_MACHINE\Hardware\Enum
HKEY_LOCAL_MACHINE\Software\Microsoft\DirectXMedia
Registry keys added are:
HKEY_CLASSES_ROOT\.dl
Removal of the replicant is also required, look for files ending
in
".exe" or ".dll" in the <drive>:\Windows\ or
<drive>:\Windows\System\
folders that use alphanumeric file names. The name of the
replicant may
be in one of the registry keys above.
A machine reboot is required to clear the existing process from
running
in memory. |
