An anti-virus expert has poured cold water on a patent from British technology firm QinetiQ that supposedly offers a new technique for tackling malicious email attachments.
New Scientist reports that the researchers at the defence technology firm have patented a technique for blocking malware in email attachments without relying on signatures. It does this by adding a string of computer code as it passes through a mail server. This code would be inserted into the header area of incoming files.
“If the file is simply opened by another program, the code is ignored,” New Scientist explains. “But if someone attempts to run it as a program in its own right, QinetiQ's code will run first - and stop the rest of the program in its tracks, either by exiting or by sending it into an infinite loop.”
A patent application (here) explains that inserted “strings are chosen to have no substantial effect on the files in normal operation, but potentially disrupt attack code located in the file”. The approach provides “mitigation for previously unidentified threats”, the application adds.
The approach is more sophisticated than simply blocking executable files at the gateway, because it potentially tackles the problem of malware camouflaged to resemble benign document files but packing a malicious punch. Such attacks are commonplace.
However David Harley, director of malware intelligence at anti-virus firm Eset, said QinetiQ's ideas had already been applied to modern anti-virus suites.
Intercepting files that could harbour virus equates to “generic filtering”, while adding code to such files amounts to “immunization”, both tried and trusted techniques. Harley's sarcastic retort to the QinetiQ's touted breakthrough can be found here.
Patents are designed to allow developers to stake out areas of technical innovation. However, in the fiercely competitive anti-virus market, they've more often been used as legal and marketing weapons. ®