This is network worm with backdoor capabilities, which spreads itself under Win32 systems. The worm was reported in-the-wild in July-August, 2000. The worm itself is Win32 executable file and about 120K long, written in MS Visual C++.
F-Secure renames the malware-modified HOSTS file to HOSTS.0. Windows then creates a new file that restores website access. The renamed file can then be deleted.
Security programs will sometimes unintentionally identify a clean program or file as malicious if its code or behavior is similar to a known harmful program or file. This is known as a False Alarm or False Positive (FP).
In most cases, a False Positive is fixed in a subsequent database release.
Usually, updating your F-Secure security product to use the latest database is enough to resolve the issue.
If you suspect a detected file is a False Positive, you can check by first updating your F-Secure security product to use the latest detection database updates, then rescanning the file.
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it to F-Secure Labs for re-analysis.
NOTE If the file was moved to quarantine, you will need to first collect the file from quarantine before you can submit it.
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Microsoft also provides enterprise-level instructions for excluding files from scanning by antivirus software.
Find the latest advice in our Community Knowledge Base.
See the manual for your F-Secure product on the Help Center.
Submit a file or URL for further analysis.
Some malicious applications will modify the Windows HOSTS file in an attempt to block access to antivirus vendor web and update servers. As a result, the websites of several antivirus vendors may become inaccessible and some antivirus programs may stop receiving updates. The Windows HOSTS file typically contains information only about the localhost. Some malware variants add more entries to the HOSTS file, attempting to block access to antivirus websites and update servers.
A normal HOSTS file will appear as follows:
# Copyright (c) 1993-1999 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # 184.108.40.206 rhino.acme.com # source server # 220.127.116.11 x.acme.com # x client host 127.0.0.1 localhost
The typical file path is:
A malware-modified version of the HOSTS file will contain additional entries:
Websites or servers configured to an IP Address of 127.0.0.1 will loop back to the local machine, making them unreachable.