What do you think - a good idea????

Discussion in 'ten-forward' started by Smokey, Sep 13, 2003.

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  1. Smokey

    Smokey Registered Member

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    ISPs should block vulnerable ports

    Blocking Windows ports at ISP level could help protect PCs being used at home, says study.


    Internet service providers (ISPs) should take security matters into their own hands by blocking access to communications ports on their customers' computers which are commonly exploited by Internet worms and other malicious programs, according to a SANS Institute report.

    Leaving the ports open offered little to customers, while needlessly exposing them to infection and making it more likely that ISPs would be overwhelmed by future virus outbreaks, the report said.

    Entitled "Internet Service Providers: The Little Man's Firewall," the report was written by Johannes Ullrich, chief technology officer of the SANS Internet Storm Centre, which uses a worldwide network of sensors to track virus outbreaks and other events on the Internet.

    The report identified four communications ports that were commonly left open on Windows machines so that users on an office or home network could share files between two Windows systems. However, those ports were never intended to be used to access files over an insecure public network like the Internet, Ullrich said.

    At least one of the ports, 135, was used by the recent W32.Blaster worm to locate and infect vulnerable Windows machines on the Internet.

    The four ports were known as handy access points for loosely secured Windows machines long before Blaster appeared in early August, Ullrich said.

    "These machines are taken out on a regular basis and used in large scale DDoS (distributed denial of service) attacks," he said. By blocking the ports centrally, ISPs would close an open doorway for attackers without requiring any action by their customers, the report said.

    Many ISPs already block some or all of the ports named, while others offer customers free personal firewall software to install on their home computers, according to Ullrich. However, home Internet users often lack the technical knowledge necessary to install and configure a firewall or even install a software patch, he said.

    Closing the ports would not protect users from all Internet threats. However, it is a simple step that would remove a common and commonly exploited security hole, Ullrich said. "The idea is to get rid of the bulk of problem, then (ISPs) can deal with the remainder of problems on a case by case basis," he said.

    Despite their popularity among virus writers and hackers, the Windows ports are not required to browse the Web or perform other common Internet activities, meaning that the change would be transparent to most ISP customers, Ullrich said.

    Customers who wanted to share files between home or office computers could still do so safely, as long as they were not doing so over the public Internet and their network was protected by a firewall, he said.

    While feasible for ISPs that serve consumers and for universities, the solution would not be right for every ISP, Ullrich acknowledged. ISPs that served corporate customers or larger, Internet backbone providers could disrupt customers' networks using a blanket approach such as the one advocated in the report, he said. "This [plan] is for the home user that knows how to turn on his computer and use a Web browser, but not much else," Ullrich said.

    "I think it's a really good idea," said Richard Smith, an independent security expert in Boston. Plugging the holes centrally would keep many Internet users from unwittingly opening their computers, and their private lives, to the Internet, he said.

    "Most users don't want to share their hard drive with the whole Internet and they don't even know they're doing it," he said.

    ISPs continue to adhere to an "old school" belief that "you've gotta keep everything [on the Internet] open," Smith said.

    Practically, however, there are few reasons to block the ports, he said. In fact, while some ISPs were dragging their feet, ISP America Online was using its firewall feature as a major marketing draw for consumers, Smith said.


    Source: IDG News Service
     
  2. meneer

    meneer Registered Member

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    I wouldn't trust isp's to secure my systems.
    Software writes ought to make sure that any open port does not create a vulnerability.
    It's not port 135,6,7,8,9 that is vulnerable, it's the software behind that port thats the problem.
    If I don't trust the software, that's my problem, I will take care of it.
    I don't mind isp's warning me, but how can they know what port is vulnerable on my system, let alone close it down for me?
    Hands of of 135. I closed it on my system, that will do fine, thank you.
     
  3. LowWaterMark

    LowWaterMark Administrator

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    At the high point of the recent worm outbreaks my ISP (SBC Global aka. a remnant of the old US "phone company") placed blocks on their perimeter routers for incoming TCP port 135. It was there many days, I forget how long exactly... It was removed after a while and by then the volume on 135/tcp was much lower, and was eclipsed by all the worm related pings.

    Yesterday, SBC techs started announcing in forums that SBC was putting this perimeter block back in place and it would be there permanently. But, that customers could contact them to opt-out of that protection if they wanted. (They didn't say exactly how they were going to be able to tailor this, customer by customer, and still keep backbone performance levels.)

    I checked it by scanning from different port scanning sites and they do indeed have the block in place now and it drops responses on 135/tcp, effectively stealthing that port from the outside.

    It'll be interesting to see if it stops there or if they end up having to remove the blocks for some reason (performance, customer complaints, whatever?)
     
  4. Smokey

    Smokey Registered Member

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    Hello LowWaterMark and Meneer!

    Practice is, that a lot of people don't know anything about the dangers coming from internet, and the (few) same people who knows a few about possible dangers are mostly not capable to do something against it.

    Just look in the Wilders Forum, there are so many questions about security and how to fix security-issue's, the Wilders is a very good place to help them but there are many other people who don't realize that internet can be very "evil".

    Just for such unknowing folks it is maybe not a bad idea that the ISP is protecting them, a little protection is better then no protection at all.

    And is it not a well-known fact, that millions of people don't install security patches/fixeso_O

    It is not always a lazy attitude, a lot of them don't realize it is necessary to install them.

    You both know enough about security, I do so (I hope :cool:) , we don't need protection by the ISP, but all the "innocent" other people?

    Ciao, Smokey
     
  5. meneer

    meneer Registered Member

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    You're right in stating that the majority of internet users need more help. But this time its 135, next time it's another issue. We can't expect others to do it all for us. Let's try to minimize the risks, by raising the quality of our resources. This week we learned that Microsoft will be distributing patches through supermarkets in Germany.
    We (or they ;) ) better try to cure the illness, not the symptoms.
     
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