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
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.Read more
Platform: Linux
Linux is a family of UNIX-influenced operating systems based on the Linux kernel and GNU tools.Description
Linux.OSF.8759 is a virus with enhanced backdoor capabilities that replicates on Linux systems and infects ELF executables.
The files infected by the virus have their file size increased by 8759 bytes. 3979 bytes belong to the actual virus code while the other 4662 belong to the code of a backdoor attached by the virus at the end of the file.
Although the backdoor code is copied along with the virus, it seems it appears designed in such way that it can be easily replaced with updated versions - the backdoor is not linked into the ELF structure, but is instead loaded and executed by the virus itself. Therefore improved versions of this virus, especially of the backdoor code can be expected in the future.
The virus infects all the files in the current directory, but avoids infecting files with file names ending with "ps".
To clarify: Files with names such as "steps", or even the popular Unix utility tool "PS" will be spared infection - as the final two lettes of their file names are "P" and "S" in sequence - "ps".
If run from a root account the virus will also attempt to infect the files from the "/bin" system directory. In all cases no more than 201 files are infected in one run.
The backdoor found in this version of the virus is listening on the UDP port 3049, or if the respective port is not available, it will try to increase the port number until one which can be used is found. Various internal commands are available to directly execute files on the target system or to launch a sniffer and forward the traffic to the other machine. The backdoor will also attempt to edit the firewall rules list and wipe out any entries that might prevent it from communicating on the hooked port, or, on the port used to communicate with the remote machine in the case of the sniffer.
Besides the above, the virus also attempts to prevent tracing by various debugging utilities by spawning a copy of itself, and attempting to debug itself from the spawned copy. If any debugger is already running, these steps will fail, and the virus will immediately terminate execution.
Another detail is if the system uptime is 5 minutes or less, the virus will also terminate execution, probably in order to prevent simple inspection on "test" machines.
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