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After years of trying, no one has yet been able to create a practical Linux virus. Rootkits, yes, viruses, no. Or have I missed something?
It's impossible to write a practical Linux virus, as the marketshare is so little it would never spread. A cross-platform virus has more potential, but the added pay-off in exchange for a massive jump in complexity and thus buggyness and detectability wouldn't be worth it.
However, to infect Linux files, it's simply a matter of infecting Windows, loading the appropiate filesystemdriver (ext2 driver for windows is available, ext3/reiser not, and fat could be used for shared files), infecting the right files, and setting permissions right. Trivial is otherwise of course
PS: hardly anyone writes viruses these days. Any self-replicating code these days is simply a worm. To infect Linux systems undetectably code-inserting will be necessary however.




Member since:
2006-01-07
To infect ELF files, the virus uses INT 80 system calls and injects its body into the file immediately after the ELF file header and before the ".text" section. This changes the entry point of the original file.
Sure, its always been possible to write a Linux virus. The problem (for virus writers) is that when you download a file with Linux, it's not executable. Thanks to umask, file permissions will be set to either chmod 644 or 600 (that is, umask 022 or 077). In order for the malware to execute, the user would first have to make it executable using the chmod command. That would be a dumb thing to do.
After years of trying, no one has yet been able to create a practical Linux virus. Rootkits, yes, viruses, no. Or have I missed something?