Under what circumstances could law enforcement hack a server?

Question

I recently read a wired article about Silk Road and the arrest of Ross Ulbricht. The article describes how an FBI agent attempted to discover the true IP address of the Silk Road Server:

Tarbell [New York FBI] threw data at Silk Road, hoping to see the leak. He entered usernames with bad passwords (and vice versa) and pasted data into input fields—all the while using regular old freeware to analyze network traffic and collect the IPs communicating with his machine.

For the sake of discussion, lets assume that the actions above are violations of the CFAA. Under what circumstances is Law Enforcement allowed to attempt unauthorized access or exceed authorized access of a system as prohibited by the CFAA or laws. Does Law Enforcement need a warrant, probable cause, etc?

Answer 1

Ok, there is an essential flaw in your question. What you stated the FBI did was not attempting an unauthorized access on the network. What they did was collect IP addresses.

This would be the same thing as a pen register, which law enforcement does not need a warrant for. Smith v. Maryland

The ninth circuit stated the same in the 2007 case US v. Forrester.

However, if you mean actual intrusion into the network, then yes, law enforcement would need a warrant. Katz

Answer 2

Disregarding the example of logging IP addresses (as Andrew said, this is not the same as "hacking a server"):

The conduct in question ("hacking" a server and exfiltrating information without the permission of the owner) would definitely constitute a "search" for purposes of the fourth amendment and other constitutional law; therefore, a warrant is required.

As for CFAA violations, the act in question states:

This section does not prohibit any lawfully authorized investigative, protective, or intelligence activity of a law enforcement agency of the United States, a State, or a political subdivision of a State, or of an intelligence agency of the United States.

(18 U.S.C. § 1030 (f) retrieved from https://www.law.cornell.edu/uscode/text/18/1030)

It would thus seem that CFAA violations are out of the question, at least so long as a warrant was obtained.

If no warrant was obtained, criminal or civil liability may arise depending on circumstances under several different laws.

As for other conduct that would not necessitate a warrant but would ordinarily be prohibited under the CFAA, there is no criminal liability.

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I am not a lawyer; I am especially not your lawyer; this is not legal advice.

Answer 3

Under "Rule 41", the FBI can hack your computer, anywhere, anytime.

The US Supreme Court has approved amendments to Rule 41, which now gives judges the authority to issue search warrants, not only for computers located in their jurisdiction but also outside their jurisdiction.

Under the original Rule 41, let’s say, a New York judge can only authorize the FBI to hack into a suspect's computer in New York. But the amended rule would now make it easier for the FBI to hack into any computer or network, literally anywhere in the world.

Here is the archive from the DoJ.

Senator Ron Wyden of Oregon has said in a statement;

These amendments will have significant consequences for Americans' privacy and the scope of the government's powers to conduct remote surveillance and searches of electronic devices.

Under the proposed rules, the government would now be able to obtain a single warrant to access and search thousands or millions of computers at once; and the vast majority of the affected computers would belong to the victims, not the perpetrators, of cybercrime.

The change grants the FBI much greater powers to hack into multiple computers within the country, and perhaps anywhere in the world, with just a single warrant authorized by any US judge (even magistrate judges). Usually, magistrate judges only issue warrants for cases within their jurisdiction.