Over the last week, "Blackworm" infected about 300,000 systems based on analysis of logs from the counter web site used by the worm to track itself. This worm is different and more serious than other worms for a number of reasons. In particular, it will overwrite a user's files on February 3rd.
At this point, the worm will be detected by up to date anti virus signatures. In order to protect yourself from data loss on February 3rd, you should use current (Jan 23rd or later) anti virus signatures. Note, however, that the malware attempts to disable/remove any anti-virus software on the system (and does this every hour while the system is up), so if the machine was infected before signatures were deployed, obviously, that anti-virus software can't be expected to clean up the infection for you.
The following file types will be overwritten by the virus: DOC, XLS, MDE, MDB, PPT, PPS, RAR, PDF, PSD, DMP, ZIP. The files are overwritten with an error message( 'DATA Error [47 0F 94 93 F4 K5]').
We will try to post more detailed cleanup instructions later. However, it is likely that you will have to rebuild the system from scratch. Obtaining good backups is critical as a first step.The first thing you should do is to update your anti virus signatures.
This page will be updated as new information becomes available. Please see the end of the page for references to other sites. Use only this url to link to this page: http://isc.sans.org/blackworm
As usual, this worm/virus has collected a number of names from various vendors. It is so far known as: Blackmal, Nyxem, MyWife, Tearec among other names. Update: we have been informed that the CME number will be 'CME-24'. cme.mitre.org
should shortly list this number.
How would I get infected?
The worm spreads via e-mail attachments or file shares. Once a system in your network is infected, it will try to infect all shared file systems it has access to. You may see a new "zip file" icon on your desktop.
What will BlackWorm do to my system?
It will disable most anti virus products and delete them. The worm will e-mail itself using a variety of extensions and file names. It will add itself to the list of auto-start programs in your registry.
Anti virus vendors offer removal tools. Microsoft provides detailed instructions
for manual removal. However, there are two important reasons to rebuild "from scratch":
- BlackWorm uses the same tricks to install itself as other viruses/worms. It may not be the only one on your system. Antivirus will not detect all viruses, and the removal tool will only remove this specific worm.
- BlackWorm will allow remote access to your system, and additional malware may have been installed via this backdoor.