Virus.Win16.RedTeam

Class Virus
Platform Win16
Description

Technical Details


This virus infects Windows EXE files (NewExe) and sends itself to Internet
by using Eudora e-mail – it is the first known virus that infects Windows
and spreads via Internet. To infect files the virus stays in Windows
memory, it then infects NE-files that are executed. To infect Eudora e-mail
the virus parses internal format of mail database and adds “infected”
messages. The virus is able to spread to the Internet only if the Eudora e-mail
system is installed on the computer, but recipients of infected messages may
use any standard e-mail system, not only Eudora.


Of course, the virus is not able to run itself automatically from an infected
message. It is not able to infect the system when an infected message is
opened and read. To spread the virus, the infected EXE attachment has to be
extracted and executed. To do exactly that (to extract and execute the
attached file) the text of the message convinces the user.


The virus was not found in-the-wild, but being released it can appear as a
real danger to the global computer network because to spread itself is uses the
most popular OS (Windows) and one of most popular e-mail systems (Eudora).


The length of virus code and data is 4766 bytes. The virus was named after
text strings present in virus body (they are encrypted in infected
files):


<<-RED TEAM->> (C) The Soul Manager.
Made in Australia – 06.97.
So, so, Herr Kurtzhals – Is F/Win able to follow The Red Team?

Infecting EXE


While infecting NewEXE files the virus does not create new segment in there
– it calculates the address of the code segment, moves the rest of file down and
writes itself to that cave. The virus increases the size of the code segment
and as a result stays as a part of legal program’s code. The virus also
fixes necessary fields in NE header and relocation tables. The virus then
modifies initial address of entry point, or patches addresses of system
routines in case of KRNL286/386.EXE.


When an infected file is executed under not infected environment, the virus
takes control and looks for Win16 Kernel module (KRNL286.EXE or
KRNL386.EXE). When this file is located, the virus opens and infects it.
The virus does not alter entry point address, it changes addresses of
WINEXEC or INITTASK routines instead. In case of Windows 3.xx the virus
sets new address of WINEXEC routine, in case of Windows95/NT the virus do
the same with INITTASK routine (because Windows95/NT do not call WINEXEC).


To separate KRNL?86.EXE modules (Windows 3.xx or Windows95/NT) the virus
uses the name if exported CALLPROC32W function, it presents only in 32-bit
Windows95/NT.


The virus then returns control to host program and does not perform any
other actions. As a result being executed for the first time the virus does
not leave any code in system memory – it only infects Windows’ Kernel16
module.

Going memory resident


When Windows is loaded with infected Kernel, the virus stays in the system
memory as a part of Kernel – no special action is necessary to do that
because code of virus is placed in the same code segment as original
Kernel’s routines. The virus also does not perform any action to hook
system events because they were already hooked while infection – address
of WINEXEC or INITTASK already points to virus handler.


Under Windows 3.xx the virus hooks WINEXEC, so it infects files that are
executed. The virus does that in quite clever way – it immediately passes
control to original WINEXEC handler and then infects a file in background,
i.e. there is no delay when application are executed under infected
environment. That is quite important for the virus because usually Windows
3.xx is installed on old slow PC, and delays on execution may warn a user.


Under Windows95/NT the virus hooks INITTASK, so it intercepts control when
programs are registering themselves in the system. The virus then with a
help of GetExePtr function gets Module Handles for all NE-application that
are active and infects them.

Infecting E-mail


While infecting a file with probability 1/8 (depending on the key that is
used to encrypt text strings) the virus modifies its code so that this-time
infected file will activate a routine that drops infected E-mail messages
to Eudora outbox. When such file is executed in directory where Eudora
databases are placed, the virus opens Eudora data files: NNDBASE.TOC,
OUT.TOC, OUT.MBX. The first file (“Nick names database”) is used by virus
to get names of recipients to whom the virus will send an infected message.
The infected message is placed to OUT.MBX (Outbox database) and necessary
references are placed to OUT.TOC file.


The message itself has a subject “Red Team”, contains the text and attached
EXE file. The text looks as follows:


———————————————————————-
Hiya!
Just thought I’d warn you about a destructive new e-mail virus.
Here is some info:
> The “Red Team” virus is a complex new computer virus that spreads via
> the Microsoft Windows operating system, and Internet E-Mail. Although
> it is not the first virus to spread via E-Mail (that was “Good Times”),
> the Red Team virus is unparalelled in its destructive capabilities.
> Further more, the virus is exceedingly common – it has already been
> reported in much of western Europe, the USA, Russia, Australia, and
> Japan. In short, everywhere.
>
> We at QUEST, have spent several weeks analysing this virus, and are proud
> to anounce that we finally have a cure! The program, named “K-RTEAM”
> (Kill Red Team), can be executed in any Microsoft Windows environment, and
> will reliably detect (and remove if nescessary) the Red Team virus from
> your system buffers.
>
> —
> Julia Blumin
> QUALCOMM Enterprise Software Technologies
> World Wide Web: http://www.qualcomm.com
The reason I thought I should warn you, is that we recently had a run in
with this beast. Luckily we managed to get a copy of the excellent
‘K-RTEAM’ programme before the destruction really started. Just in case
you should suffer the same misfortune, I have included this programme for
you too.
Bye!
P.S. Make sure you warn all your friends of this new threat!
———————————————————————-

This text in the virus body is compressed, so the virus decompresses it
before saving to Eudora outbox. The attached EXE file has NE header and is
named as K-RTEAM.EXE (“Kill Red Team”), it has 6351 bytes of length. It is
an infected do-nothing program (the virus creates it on the C: drive –
C:K-RTEAM.EXE) that only spreads the virus on computer. At the header and
end of this file there are the text strings:

K-RTEAM – Red Team Anti-Virus
K-RTEAM
Red Team Virus Found!
Remove Virus?
Virus Removed!
Could not Remove Virus!

The virus does not send messages twice from the same infected computer. To
do that the virus creates the RTBASE.TOC file while sending infected
messages. Next time the virus will look for that file and terminate E-mail
infection routine, if this file presents in directory.

In-lab


The virus replicates itself under Windows 3.xx and had no side effects
during experiments in lab – all files were infected correctly, the programs
were not corrupted and Windows did not display any warning/error messages.


The virus also stored its dropper in the Eudora outbox with no problems. The
infected messages then were sent via Internet and correctly received.


Under Windows95/NT the virus has a problem – it cannot infect KRNL386.EXE
and as a result cannot install itself memory resident. The bug is quite
stupid – the virus reserves Word (DW) for variable “NE Header Offset”, but
uses it as DoubleWord (DD). The second Word of that DoubleWord is Windows
version flag: 0 if Windows3.xx, FFFFh if Windows95/NT. So under
Windows95/NT the virus gets wrong value from that variable.


Despite this, the files that were infected under Windows 3.xx do work
under Windows95/NT without any problem and may infect Eudora database as
well as under Windows 3.xx. Moreover, that stupid bug may be easily fixed
and a Windows95 compatible version might be released by the virus author.