One of the provisions of the Communications Decency Act (Section 230 of the US Code) established a safe harbor for ISPs so that they couldn't be held liable for the speech of their users. If you take umbrage at something someone said on the Internet, your remedy is to sue the speaker, not their ISP or telephone company.
That safe harbor is pretty well known, however there is another provision in title 230 that hasn't received quite as much attention. Subsection (c) (2) provides protection for 'Good Samaritan' blocking of offensive material. This states that service providers are not liable for voluntarily blocking access to offensive or otherwise objectionable material.
Kaspersky's anti-malware product displays warnings and blocks the operation of Zango's software, which is classified as adware. Zango wasn't very fond of this practice and thus sued Kaspersky for tortuous interference in Zango's business. Kasperksy was able to obtain a summary judgment in trial court because of the 230 safe harbor. Zango appealed to the US Court of Appeals for the Ninth Circuit. That court recently handed down a judgment for Kaspersky.
One of the arguments Zango raised in the appeal was that Kaspersky was selling a product, not offering an interactive online service. The court found that Kaspersky's products count as an interactive computer service based on the fact that they disseminate updates via the Internet. This definition of interactive computer service should be broad enough to cover a good chunk of the security industry.
I am not a lawyer, this post does not constitute legal advice, nor would I be competent to offer such advice. The following is just the speculation of a security geek that thinks that our legal system should be accessible to anyone willing to do the requisite research. That said, for those organizations that would not be covered, I wonder if including a feature that allows users to update content via the Internet would be enough to extend the liability protection to that organization.
Another interesting side effect of including security services under the liability shield is that it could be used to try to shield an individual security researcher from liability. The exact wording of the statue states that no provider or user of an interactive service shall be held liable for:
"any action taken to enable or make available to information content providers
or others the technical means to restrict access to [objectionable content]"
If a researcher were to publish security research online that would allow others to develop countermeasures, that sure sounds a whole lot like it would be included in that definition to me. In theory, this could be used to shield researchers who publish vulnerability information. While this law may offer protection to those who disclose information in a number of different ways, SecureWorks supports and follows guidelines for responsible disclosure.
If this legal tactic were to be accepted in a court of law, there could be two unintended restrictions to when this defense could be employed, that some might consider leading to undesirable outcomes.
First, as the law only protects users or providers of interactive services, this liability shield may not work for someone presenting information in person or dead tree format. Second, if the requirement is to give information which would allow others to be able to restrict access, it might require enough information to write a signature to block the attack. So this could lead to a situation where revealing information online, full disclosure style, could have more legal protections then giving a talk at Blackhat for example. But then again, perhaps videotaping the talk and putting it online would be enough for conferences to be counted as an interactive service. It would be nice to have another tool to defend against legal threats that have unfortunately prevented some security talks.