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The Federal Government’s Power to Use Computer Hacking to Investigate Criminal Activity

December 2016
Privacy in Focus

On December 1, 2016, amendments to Federal Rule of Criminal Procedure 41 (Rule 41) went into effect, granting law enforcement enhanced powers to investigate computer crimes. The scope and wisdom of these amendments have been hotly debated. Privacy advocates have claimed that the Federal Bureau of Investigation (FBI) can now engage in mass hacking of targets. The U.S. Department of Justice (DOJ) responded that the change is limited to mere considerations of venue. This article seeks to separate fact from rhetoric and describe the actual scope of the amendments.

Background on Rule 41 and the Fourth Amendment

The Fourth Amendment to the United States Constitution provides limits on the federal government’s power to search property as part of a criminal investigation. In general, the Fourth Amendment provides two important limitations. First, searches must be done pursuant to warrants that are supported by probable cause. See, e.g., Illinois v. Gates, 462 U.S. 213 231 (1983); United States v. McLamb, 2016 WL 6963046 (E.D.Va. 2016). Second, search warrants must describe with particularity the place to be searched, i.e., a specific address of a house that is believed to contain evidence of a crime. See, e.g., United States v. Henderson, 2016 WL 4549108 (N.D.Ca. 2016) (“Particularity means the warrant must make clear exactly what it is that he or she is authorized to search for and seize.”).

Rule 41 sets out the procedures for how law enforcement can obtain a warrant, including authorizing federal magistrate judges to issue warrants. Under the previous version of Rule 41, magistrate judges, with exceptions, could only issue warrants for property that was located within their district. So, as a general matter, a magistrate judge in one state could not sign a search warrant allowing agents to search a house in another state.

Background on the Dark Web

These basic Fourth Amendment safeguards for obtaining search warrants are routinely applied in investigations of computer crimes. However, the decentralized and anonymous nature of the dark web presents more difficult questions. To understand why, some background on the dark web is necessary.

The dark web can only be accessed by special software, most notably The Onion Router, which is commonly referred to as Tor. All Internet traffic on Tor is anonymous. Tor sends each communication through numerous “nodes” or routers, thereby stripping the original or true IP address of the person connecting to the dark web. Similarly, web servers on Tor send all of their traffic through numerous routers, allowing for the location and true IP address of the server to be masked.

While the social utility of Tor is constantly debated, there is no question that criminals love it. The benefit of anonymous activity facilitates myriad criminal activities, such as drug trafficking, terrorism, murder-for-hire, and child exploitation.

The Playpen Investigation

A recent FBI investigation into a child exploitation website known as Playpen illustrates how Tor pushed the limits of the previous incarnation of Rule 41. Playpen was devoted to child pornography, and it was hosted on Tor, meaning savvy pedophiles could access it anonymously. In 2015, the FBI had a break: They were able to seize the servers that hosted Playpen. But, even with the servers, they could not tell who was accessing the site—Tor prevented them from seeing the true IP address of the targets.

The FBI developed a work-around: a small bit of code that was downloaded to the home computer of anyone who accessed the Playpen website and entered a username and password. Once downloaded to the target’s computer, the code secretly sent the target’s true IP address to servers that were maintained by the FBI. The FBI referred to the code as a Network Investigative Technique (NIT). Privacy advocates are more blunt. They call it malware and computer hacking.

Terminology aside, the code was a search. It went onto an individual’s computer and searched that computer for its true IP address. As such, the FBI obtained a warrant to conduct the search. The Playpen servers were located in the Eastern District of Virginia, and the FBI obtained a warrant from a magistrate judge there to deploy the NIT and search for the true IP addresses of the users of the Playpen website.

The concern, however, is that the users of Playpen could have been anywhere in the world. Their IP addresses, and therefore physical location, were unknown. Under Rule 41, what was the authority of the magistrate judge in Virginia to issue a warrant to allow for a NIT to search computers that would almost certainly be located outside of Virginia? Moreover, if the magistrate judge in Virginia could not properly issue the warrant, who could? Because Tor is anonymous, law enforcement could not at the outset identify the location of any individual target and, therefore, could not determine in which district to seek a warrant.

Playpen Decisions

Using the NIT, the FBI collected the true IP addresses of over a hundred users of the Playpen website. Using those IP addresses, law enforcement across the country obtained a second set of warrants. Now able to identify the location of the computers using Playpen to view child pornography, the FBI obtained warrants for those individuals’ houses. In the subsequent criminal cases, several defendants have challenged the original warrant authorizing the NIT as a violation of Rule 41. The courts’ decisions have predominately—but not uniformly—upheld the validity of the search under Rule 41. See, e.g., United States v. Henderson, 2016 WL 4549108 (N.D.Ca. 2016), (warrant was valid under Rule 41); United States v. Allain, 2016 WL 5660452, (D. Mass. 2016), (same); but see United States v. Levin, 2016 WL 2596010 (D.Mass. 2016) (warrant violated Rule 41’s jurisdictional requirement and was void ab initio). The split among the reviewing courts shows that this type of investigative technique is a close call under the previous version of Rule 41.

Amendments to Rule 41

The DOJ, most notably in a series of blog posts by Assistant Attorney General Leslie R. Caldwell, advocated for amending Rule 41 to make it clear that a magistrate judge can issue a warrant under these circumstances. See November 21, 2016 Blog Post by AAG Caldwell, Ensuring Tech-Savvy Criminals Do Not Have Immunity From Investigation. On December 1, those amendments went into effect. Specifically, Rule 41(b)(6) now states, “a magistrate judge with authority in any district where activities related to a crime may have occurred has authority to issue a warrant to use remote access to search electronic storage media and to seize or copy electronically stored information located within or outside that district if: (A) the district where the media or information is located has been concealed through technological means.” This provision allows for precisely the type of NITs that were used in the Playpen investigation.

Concerns About Law Enforcement Engaging in Computer Hacking

Privacy advocates, including the American Civil Liberties Union (ACLU) and the Electronic Freedom Foundation (EFF), joined by numerous companies including Google and PayPal, opposed the amendments. The main concern voiced by the opponents is that “Congress and the public need adequate time to have an informed debate about government hacking—and an opportunity to consider what safeguards must be instituted—before the usage of these dangerous investigative tools becomes widespread.” See June 21, 2016 Letter to Congress signed by dozens of organizations, including ACLU, EFF, Google, and PayPal.

These concerns, however, ignore the fact that the amendments to Rule 41 do not authorize the government to engage in hacking—the government already had that power, so long as the hacking is a search that is deemed reasonable under the Fourth Amendment and is pursuant to a warrant supported by probable cause. To put the powers of law enforcement in some perspective, consider the second set of warrants in the Playpen investigation. Far more intrusive than hacking, those warrants allowed armed federal agents to enter peoples’ homes without consent, seize every item of computer media in house, and conduct a detailed forensic analysis of that media.

Further, the amendments to Rule 41 do not in any way abrogate the traditional safeguards for all law enforcement searches: the Fourth Amendment’s protections of a warrant supported by probable cause and a particular description of the place to be searched. Again, the Playpen investigation shows how those protections have real meaning even in the context of investigations into computer crimes. First, the warrant authorizing the NITs was supported by probable cause. See, e.g., United States v. Allain, 2016 WL 5660452 (Probable cause supported by “the appearance and content of Playpen, the fact that it was a hidden service on the Tor network, and its registration terms.”). The only computers that were searched were those of people who voluntarily visited a secret website devoted to child pornography and logged into that website with a username and password. That is certainly a sufficient connection to criminal activity to justify a warrant. Second, the property to be searched was described with particularity. See, e.g., United States v. Henderson, 2016 WL 4549108 (The description of Attachment A of the warrant met the particularity requirement because it was “limited only to individuals that log onto the Playpen website using a username and password.”); United States v. Anzalone, 2016 WL 5339723 (D.Mass. 2016).

Privacy advocates have raised other concerns as well, including the potential that law enforcement may inadvertently cause damage when engaging in hacking pursuant to a warrant. That is certainly a valid consideration. But, again, the risk of collateral damage is inherent in any non-consensual search by law enforcement. Certainly the risk of collateral damage by a NIT is less than that of armed agents entering a person’s house without warning.

Further, as with any new Rule, courts will have to determine the scope of Rule 41(b)’s limitation that NITs can only be used outside of a magistrate judge’s district if the target’s location “has been concealed through technological means.” The change will also put additional pressure on magistrate judges to understand the technical searches that they are being asked to evaluate. While these issues will certainly require attention, they are not as grave as the specter of rogue computer hacking by the FBI.

The last several years have seen an emerging tension between industry and law enforcement, epitomized by conflicts like that between Apple and the FBI about encryption and the search of the iPhone of the San Bernardino shooters. Every indication is that this tension will only increase as private industry grapples with wanting to protect itself and its customers’ data from governmental intervention. The debate over the amendments to Rule 41 has become a flash point in that debate. But, a closer examination of how the powers of law enforcement were—and were not—expanded by the amendments shows that the rhetoric of this debate may have outpaced the actual increase in governmental power.