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: Virus

Viruses replicate on the resources of the local machine. Unlike worms, viruses do not use network services to propagate or penetrate other computers. A copy of a virus will reach remote computers only if the infected object is, for some reason unrelated to the virus function, activated on another computer. For example: when infecting accessible disks, a virus penetrates a file located on a network resource a virus copies itself to a removable storage device or infects a file on a removable device a user sends an email with an infected attachment.

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Platform: Win16

No platform description


Technical Details

It is a very dangerous memory resident parasitic virus. When an infected program is executed, the virus infects the Windows KERNEL file. When an infected KERNEL is executed, the virus hooks the WinExec function and writes itself to the end of NewEXE files that are executed.

To infect the KERNEL the virus gets the access to that file by using documented function GetModuleHandle, then the virus writes its code to the KERNEL file (KRNL286.EXE or KRNL386.EXE), and patches the system data in that file so, that the address of WinExec routine in the infected KERNEL points to the virus code. Then the virus returns the control to the host NewEXE file. So, when the infected file is executed, the virus infects only the KERNEL file.

When the system with infected KERNEL is loading, the virus stays memory resident as a part of KERNEL code, and patched WinExec address points to the virus handler. When an NewEXE file is executed, the virus infects it.

The virus separates the infected and not infected files by using the ID-label "LROY" that the virus writes to the checksum field in NewEXE header while infecting a file.

Depending on the system date and the day number the virus displays the message box bearing the title:

Chicago 7: Cyber riot
and the messages inside. The virus displays different messages, in April starting from 29th and on May 1st:
Happy anniversary, Los Angeles!
Anarchists of the world, unite!
On any Friday before the 13th of a month:
When the levee breaks, I have no place to stay...
(Crying won't help you. Praying won't do you no good.)
On March 6 and in December from 1st to 26th:
Save the Whale, harpoon a fat cat.
After displaying the message, the virus erases disk sectors.

The virus also contains the text strings:

USER KERNEL Chicago-7 CyberRiot, 15.1.1993 Klash (Werner L.)
Sommer 1993: 15 Windowscomputerviren
Coming soon: Diet riot. Same great aftertaste--fewer bytes.
Source code avaiable for $15,000,000. Serious inquiries only.
Why does IBM need to lay me off? Oh well, their loss.
McAfee's FUD equation: !!!!!!+??????=$$$$$$
Convict the pigs
This program was written in the cities of Hamburg, Chicago, Seattle and
Berkeley. Copyright (C) 1993 Klash/Skism/George J/Phalcon/Henry Buscombe
and 2 ex-Softies, collectively known as the Chicago 7.

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