Detect date

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.


Using the driver:

The rootkit connects as a driver filter to the following file system arrangements:




and thereby obtains control of the infected computer's file system. The rootkit hides files with names like this:
where <rnd> is a random four-digit number, e.g.:


It also hides files with the extension LNK and a file size equal to 4171 bytes. The rootkit file has a Realtek Semiconductor Corp digital signature. It contains the following string:

Using the driver:
The malicious program injects malicious code into the user mode's processes. To do this, it loads a DLL dynamic library into the following system processes:




after which, their module lists contain libraries with names like this:



where <rnd> is a random hexadecimal number. The injected code is found in the file:
in encrypted form.

The injected code contains the malicious program's main functionality. This includes:

  • Propagation via removable media.
  • Monitoring for the operation of the Siemens Step7 system. To do this, the rootkit driver injects its intermediary library to the process s7tgtopx.exe, replacing the original s7otbxsx.dll, which emulates the operation of the following API functions:
    collecting various information about how the system works.
  • Execution of SQL requests. The malware obtains a list of computers on the local network and checks whether any of them is currently running Microsoft SQL Server, which serves the process visualization system Siemens WinCC. If the server is detected, the malware attempts to connect to the database with the username and password WinCCConnect/2WSXcder (CVE-2010-2772), after which it attempts to obtain information about tables, such as:
  • It collects information from files with the following extensions:
    These are created through the Siemens Step7 system. A search for files is carried out on the whole of the computer's hard disk.
  • It sends the collected information via the Internet to the malicious user's server in encrypted form.

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