| By Ian “Gizmo” Richards |
Even when you obtain a new program from a trusted source, there’s always a nagging doubt whether the file is really clean.
You can use the following techniques to check files for any possible malware infection before you start opening them.
Antivirus software is just the beginning
Most people rely on their antivirus scanner to protect them from infected software. If a program they download scans clean, they feel reasonably confident that it can be installed safely.
I’m afraid it’s not quite so simple. It’s very possible that a file can scan clean and still be infected. Allow me to explain why.
First, AV scanners can detect only the malware contained in their signature databases. If the file is infected with a new malware program yet to be listed in the database, the file won’t be detected by simple scanning.
Second, merely scanning a file for malware isn’t particularly effective. That’s because many modern malware programs are deliberately constructed to avoid detection by antivirus scanners. There are many different techniques used by malware to avoid detection. One of the most common, polymorphism, packages the malware so that no two copies are alike. This makes detection of characteristic signatures very difficult.