Friday I got support ticket from one of our larger customers, Ohio State University. They were attempting to download and update one of their Symantec antivirus products but the SonicWALL was preventing the file transfer saying that it was infected with the "Zapchast virus". The support folks have access to their SonicWALL (while most of our customers do not). They knew that this was a false alarm and a mistake. So they went into the SonicWALL and disabled the antivirus from that zone. That ought to do it, right?
Here is one of my many complaints about SonicWALL products. When you identify something that isn't working correctly you should be able to easily turn it off, or make an exclusion. While SonicWALL's do give you the ability to exclude certain IP addresses from the antivirus feature, it doesn't work. That's right. You can add those addresses to the exclusion list and it will exclude them. Bit if you have one of these hum-dinger mistake signatures that feature simply "does not work". Next, I would normally recommend removing the antivirus feature from the network zone. That's Network > Zones, from the administration pages. Yet, remove it from the zone all you like. That won't work either.
The only sure fire way to stop the SonicWALL from blocking something like this is to disable the entire antivirus, anti-spyware, and intrusion prevention engines and then reboot the box. Obviously, that is not a viable solution for a University who is supporting thousands of simultaneous connections. Not to mention that this seems pretty unnecessary just to download a single file that you need.
I have had similar problems with intrusion prevention signatures. SonicWALL will write a new signature and put it out there, only to find that it's causing horrible problems and stopping all sorts of legitimate traffic. They will eventually get around to fixing or removing the signature but until an update is available you are in trouble. The difference is that you can disable an intrusion prevention signature. You can't disable a virus signature. You have to understand the logic in that. Intrusion detection is bound to have false positives. Someone may be trying to 'break in' to your network, but that could be a legitimate user trying to run some sort of cryptic report (which looks like an attack). Virus's on the other hand - are always virus's. It's not as if it "might be a virus, might not be".
I suppose the problem here, is that SonicWALL needs to admit that they make mistakes (often) and give us the ability to work around them. Until then we will continue to tell customers that "they are working on it" ... and we will hope that they actually ARE working on it.
Until next time,