Dr Web Anti-virus protects peer-to-peer networks from a dangers polymorphic Win32Polipos

Released on = April 20, 2006, 12:20 am

Press Release Author = Doctor Web, Ltd.

Industry = Computers

Press Release Summary =
Virus monitoring service of Doctor Web, Ltd. warns users of peer-to-peer networks on
a dangerous polymorphic virus named Win32.Polipos which emerged around a months ago
and is actively propagating in different file sharing networks.

Press Release Body =

Virus monitoring service of Doctor Web, Ltd. warns users of peer-to-peer networks on
a dangerous polymorphic virus named Win32.Polipos which emerged around a months ago
and is actively propagating in different file sharing networks.

The propagation of Win32.Polipos began in March. It was added to Dr.Web virus base
on March 20, 2006 and since that time it is no more a danger for users of Dr.Web
Anti-virus.

Apart from the complicated polymorphic technique used by the virus writer, the virus
also has a dangerous function of "neutralizing\" certain antivirus and security
programs. Fluently spreading across P2Ps, the virus infiltrates computers connected
to these networks and, being run, secretly makes them accessible to public of
P2P-networks.

The virus infected Windows executables by writing the code of the polymorphic
decoder into unused spaces of code sections, as if "covering the body of the victim
with own spots". When doing this, the virus creates a new section and places there
its main encoded code, moving the resource section, if any exists, below. When
implanting into a file it does not modify the original entry point, but replaces
addresses of calls of API, selected at random, with the start address of the virus.

When the virus is launched, it implants its code into all run processes, except for
the following:

savedump, dumprep, dwwin, drwtsn32, drwatson, kernel32.dll
smss, csrss, spoolsv, ctfmon, temp

Thus, several copies of the virus stay in the computer memory, each of them is
responsible for a definite activity, for example search for files for infection,
infection of files, interaction with P2Ps based on Gnutella networks, etc. Infected
files become open for members of this network.
Resident copies of Win32.Polipos intercept the following API functions -
ExitProcess, CreateProcess, CreateFileA, LoadLibraryExA, SearchPathA,
CreateProcessW, CreateFileW, LoadLibraryExW, SearchPathW. When any of these
functions is called, new files get infected. When the control is passed to a
victimized file with overlays (sfx-archives, installation files , etc.) the virus
tries to create the original copy of file in the temporary directory with the name
ptf*.tmp and runs it. This is done to evade the integrity check used by certain
installers.

The spread of such virus undoubtly caused the anxiety of users of P2Ps and it is
strange enough that though the presence in networks of Win32.Polipos is not a secret
for any body for a whole month, Dr.Web Anti-virus long remained the only anti-virus
to detect it.

At the beginning of the epidemics the technical support service of Doctor Web, Ltd.
received users' requests about false alarms to "clean files". But Dr.Web analysts
proved the existence of a new virus. Dr.Web Anti-virus successfully detects
different modifications of this complicated polymorphic virus due to the high
technological level of the Dr.Web engine.

At present, Virus monitoring service of Doctor Web, Ltd. designed the curing
procedure for files infected with Win32.Polipos. It was done for users whose
anti-virus programs still do not detect this virus and whose computers, though
protected by other anti-virus programs, are infected with the virus and let it
infect other computers. The curing technique is rather difficult, as it requires
processing of a complicated crypt algorithm XTEA, and the decoding of the virus code
can take much time. You should not download any additional curing utilities to cure
the infected files, just use Dr.Web Anti-virus and update the virus bases on time.



Web Site = http://www.drweb.com

Contact Details = Russia, Moscow, 3-ja ulitsa Yamskogo polya, vl.2, k.12A
pr@drweb.com
www.drweb.com

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