Alcon, or RSY is a computer virus that was discovered to be spreading in Europe in 1997. It is a boot virus.

Infection

Alcon is a standard boot sector virus that spreads via floppies. Instead of the MBR

Master boot record

A master boot record is a type of boot sector popularized by the IBM Personal Computer. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk...

, it infects the DBR, making some antivirus programs miss it.

Symptoms

Alcon contains no notable symptoms beyond one extremely damaging one, which is overwriting random information. Assuming that the overwrites are subtle, this may result in significant compounding data overtime, as Alcon is a slow damager.

Alcon contains the text "R.SY".

Prevalence

Alcon was listed as being spreading by the WildListhttp://www.parc.xerox.com/about/history/default.html from April 1998 to July 1999. F-Secure lists it as having been common in Europe throughout 1997. Like most boot viruses, it is near extinct, although it was certainly in the last wave of boot viruses, so cases involving Alcon may be false positives, but may also be due to older, unused infected disks resurfacing.

Aliases and variants

Alcon's most common alias is RSY, based on inclusions in the virus code. Other aliases include Kendesm, Ken&Desmond, and Ether. It is unknown where these names are derived from.

This virus is unrelated to W32/Alcon.