NAV has the ability to detect unknown viruses of various types using heuristic algorithms known as
Bloodhound. This technology uses an expert system to analyze the cataloged behaviors and assess the likelihood of viral infection. Bloodhound is not the name of a virus, but a message displayed by NAV when it thinks it
may have found a new virus. According to
Symantec, Bloodhound detects up to 80% of new and unknown executable viruses, and 90% of new and unknown macro viruses.
Heuristic analysis is the ability of an anti-virus program to detect new viruses before the vendor can get samples and update the program's definitions for detection. Heuristics uses non-specific detection methods to find new or unknown malware which allows the anti-virus to detect and stop if before doing any harm to your system. The techniques involves inspecting the code in a file to see if it contains virus-like characteristics. If the number of these characteristics/instructions exceeds a pre-defined threshold, the file is flagged as a
possible virus.
The
disadvantage to using heuristics is that it is not as reliable as signature-based detection (blacklisting) and can potentially increase the chances that a non-malicious program is flagged as malicious. With heuristics, there is always a
potential risk for a "
False Positive" if virus detection technology (AutoProtect Settings) are set to High for Bloodhound and the heuristic analysis flags a file as
suspicious or
infected that contains no malware. You may want to
Reset Bloodhound to default settings and try scanning again.
Did your anti-virus provide a specific file name associated with Downloader and where is it located (file path) at on your system?
You can also do this:
Download
Sysclean Package and the latest
Virus Pattern Files -
(Pattern files are usually named lptxxx.zip, where xxx is the pattern file number).
- Be sure to print out and follow the instructions provided in the How to Use System Cleaner for performing a scan.
- This tool generates a log file (sysclean.log) in the same folder where the scan is completed - C:\Sysclean.
- When using Sysclean its best to use the Administrator's account or an account with Administrative rights otherwise you will not have access rights to scan some locations. You can also Use the "Run As" Command to Start a Program as an Administrator. Even when doing that, the scanning process may result in "Access Denied" messages for some files. This is normal because these files are protected by the system.