Kaspersky Threats

Parent class: VirWare

Viruses and worms are malicious programs that self-replicate on computers or via computer networks without the user being aware; each subsequent copy of such malicious programs is also able to self-replicate. Malicious programs which spread via networks or infect remote machines when commanded to do so by the “owner” (e.g. Backdoors) or programs that create multiple copies that are unable to self-replicate are not part of the Viruses and Worms subclass. The main characteristic used to determine whether or not a program is classified as a separate behaviour within the Viruses and Worms subclass is how the program propagates (i.e. how the malicious program spreads copies of itself via local or network resources.) Most known worms are spread as files sent as email attachments, via a link to a web or FTP resource, via a link sent in an ICQ or IRC message, via P2P file sharing networks etc. Some worms spread as network packets; these directly penetrate the computer memory, and the worm code is then activated. Worms use the following techniques to penetrate remote computers and launch copies of themselves: social engineering (for example, an email message suggesting the user opens an attached file), exploiting network configuration errors (such as copying to a fully accessible disk), and exploiting loopholes in operating system and application security. Viruses can be divided in accordance with the method used to infect a computer:

file viruses
boot sector viruses
macro viruses
script viruses

Any program within this subclass can have additional Trojan functions. It should also be noted that many worms use more than one method in order to spread copies via networks.

Class: Worm

Worms spread on computer networks via network resources. Unlike Net-Worms, a user must launch a Worm in order for it to be activated. This kind of worm searches remote computer networks and copies itself to directories that are read/write accessible (if it finds any). Furthermore, these worms either use built-in operating system functions to search for accessible network directories and/or they randomly search for computers on the Internet, connect to them, and attempt to gain full access to the disks of these computers. This category also covers those worms which, for one reason or another, do not fit into any of the other categories defined above (e.g. worms for mobile devices).

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Platform: Win32

Win32 is an API on Windows NT-based operating systems (Windows XP, Windows 7, etc.) that supports execution of 32-bit applications. One of the most widespread programming platforms in the world.

Description

Technical Details

This is a local network worm that spreads on Win32 systems. The worm itself is a Win32 executable file about 60K in length, and it is written in MS Visual C++. The known worm version is encrypted by PELock Win32 EXE file protection tool.

The spreading process distributes the worm copy throughout a local network to drives that are shared for reading/writing. The worm enumerates network resources (shared directories) and looks for WINDOWS in there. If such a subdirectory is found, the worm copies itself to there with a random EXE name (for exemple, RLITK.EXE, STNXOUL.EXE) and registers that copy in a WIN.INI file, [windows] section, "Run=" command (auto-run command). As a result, the worm is able to infect Win9x machines only (WinNT doesn't use WIN.INI files, rather it uses a registry instead).

While modifying the WIN.INI file, the worm uses a temporary WIN.HAI file; thus, the worm is named in such a way.

The worm also scans the local network and other IP addresses. While scanning, the worm simply obtains the next IP address, tries to open a connection to that machine, and then immediatly closes the connection, and does not use the result of the connection in any way.

The scanning algorithm appears as follows: the worm obtains the current machine's IP address as a "base address," then runs two processes: the first one scans all IP addesses by incrementing the base address, and the second one does this by decreasing the base address.

For example, if a current machine's IP is 192.3.2.1, the worm will scan:

 first process   second process

 192.3.2.1       192.3.2.1
 192.3.2.2       192.3.1.255
 192.3.2.3       192.3.1.254
 192.3.2.4       192.3.1.253
 ...             ...
 192.3.2.255     192.3.1.1
 192.3.3.1       192.2.255.255
 ...             ...
 192.3.255.255   192.1.1.1
 192.4.1.1       191.255.255.255

Find out the statistics of the vulnerabilities spreading in your region on statistics.securelist.com

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