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Re: Customer-facing ACLs
Dave Pooser wrote:
I can understand the logic of dropping the port, but theres some additional thought involved when looking at Port 22 - maybe i'm not well-read enough, but the bots I've seen that are doing SSH scans, etc, are not usually on Windows systems. I can figure them working on Linux, MacOS systems - but surely the vast majority of 'vulnerable' hosts are those running OS's coming from our favourite megacorp? Which typically don't come shipped with neither SSH server nor SSH client... ?
Or are simply writing a bot that sens TCP SYNs to port 22 and are reporting those hosts that responds with a SYN ACK back to the C&C. Then the C&C can direct other compromised hosts with a more complete rootkit (or compromised *nix host) to do brute-force userid/password guessing.
Half the Mac users? You think? I know a dozen or so sysadmins who use Macs, and about a hundred users who wouldn't know SSH from PCP; I think that's probably a slightly skewed sample considering I'm a Mac geek who hangs around with Mac geeks, and I'd guess the consumer users are a larger percentage of the real-life population. I'd expect the number of folks who want SSH unblocked to be under 1% of a consumer broadband network, and probably closer to 0.1% or so. And again, it ought to be trivial to let your users unblock the system, either via phone call or via self-service Web page (though in the latter case you'd better use a captcha or something so the bot doesn't automatically unblock itself).
Agreed. I don't think the end-user's OS makes them more or less likely to be using SSH unless the OS is a BSD or Linux (then I suspect you'd get a disproportionate # of SSH users compared to the other more simple OSs).