For the past several days, ISC have received all kinds of emails about the recent increase in scanning on port 139. One of loyal readers out there on the ‘Information SuperHighway’, Alex Pettinger, wrote and and gave us some netstat and fport outputs from one of his machines that seemed to be affected by the worm, (as well as a nice copy of it). It appears, in typical antivirus fashion to be named several things: McAfee is calling it “W32/SDbot.worm!MS06-040“, Sophos is calling it, “W32/Vanebot-A“, and Symantec is calling it, “W32.Randex.GEL“. (Yes, it’s been out for a couple days)
Let’s take a look at this bad boy shall we? How does it spread.. well, it uses: MS04-007, MS05-017, MS05-039, and of course, our favorite bug of the moment, MS06-040.
This one should be relatively easy to catch, look for machines pounding away over port 139 (from reader submissions it’s about 150 machines in just a few seconds, so it should be noisy), look for connections via IRC to “forum.ednet.es” over port 4915. (Until the next variant changes it, and we know it will). It has the ability to do a bunch of things including spreading to network shares..
For protect your PC block 139 and 445 at the router/firewall. Netbios traffic shouldn’t be allowed to exit or enter your network from egress points anyway.
Update your antivirus. At least daily. Patch your Windows.