Posted by Martijn Grooten on May 24, 2018
When in our VB100 test lab we set up an anti-virus product, one of the first things we do is to see if it works by making it scan the EICAR test file. This 68-byte file is supposed to be detected by any anti-virus product but does not perform any malicious activities and thus can safely be copied to any computer.
As Randy Abrams (then at Microsoft, now Senior Security Analyst at Webroot) explained in a paper presented at the VB99 conference, such a file was particularly important at a time when the majority of malware encountered consisted of self-replicating viruses. This is less the case today, but there are still many cases in which one needs a reliably detected but otherwise harmless file, and the EICAR test file thus remains in wide use.
Not all of this use is totally harmless though: the fact that a specific 68-byte string can trigger an anti-virus alert has been used in proof-of-concept denial-of-service attacks, for example by adding the string to a blockchain.
Today, for Throwback Thursday, we republish Randy's 1999 paper in both HTML and PDF format.