Monday, November 26, 2012

The Wireless Signal, Moocherhunter and the 4th Amendment

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After being charged with possessing child pornography in violation of 18 U.S. Code § 2252(a)(4)(B), Richard Stanley moved to suppress certain evidence.  U.S. v. Stanley, 2012 WL 5512987 (U.S. District Court for the Western District of Pennsylvania 2012).   

On May 24, 2012, the district court judge held a hearing on his motion, at which it “heard testimony from Cpl. Robert Erdely (retired) of the Pennsylvania State Police” and received “certain exhibits” into evidence.  U.S. v. Stanley, supra. In this opinion, the judge is ruling on the motion to suppress.

In the paragraphs below, I’m summarizing the judge’s very detailed description of the investigation that led to the charges against Stanley.  Everything below comes from the opinion cited above.  U.S. v. Stanley, supra.

On November 11, 2010, Erdely was investigating the distribution of child pornography files over peer-to-peer file-sharing networks when he discovered a computer sharing seventy-seven files on the Gnutella network. By using hash values for known child pornography, he confirmed that “several” of the files contained child pornography. U.S. v. Stanley, supra.

Erdely identified the globally unique identification (“GUTD”) of the person sharing these files on the Gnutella network as “8754E6525772BA0134C4C6CACF12E300” (“300 GUID”).  U.S. v. Stanley, supra. He also identified that the subject computer was using an IP address of “98.236.6.174.” Using publically available records, Erdely determined that the IP address was subscribed to through Comcast Cable and got a court order directing Comcast to identify the subscriber of that address. U.S. v. Stanley, supra.  Comcast said it was assigned to William Kozikowski and provided his home address in Allegheny County.

Based on the information above, Erdely obtained and executed a search warrant for Kozikowski's home. He found two computers, but neither contained file-sharing software with the 300 GUID. Erdely learned that Kozikowski was running a wireless network in which one computer was connected to the wireless router via a cable, while another was connected to it via a signal. Kozikowski's network was unsecured, i.e., did not require users to enter a username and password to connect. Kozikowski told Erdely he had not given anyone outside his home permission to use his internet connection. U.S. v. Stanley, supra.


Kozikowski left his router unsecured and let Erdely place a computer in his home and connect it to his router. On January 19, 2011, Erdely was using a computer system in Harrisburg that let him view the search results of other officers’ investigations of child pornography.  He learned that Jessica Eger, an employee of the Pennsylvania Attorney General's Office and Paula Hoffa, an investigator with the Hartland Police Department, each identified a computer sharing child pornography that had the same 300 GUTD as the subject computer identified by Erdely. U.S. v. Stanley, supra.

After learning about their investigations, Erdely logged into the computer in Kozikowski's home from his computer in Harrisburg and examined the configuration of his wireless router.  The 215 IP address was assigned to Kozikowski's router; its logs showed a computer connected to it with a private IP address of “192.168.2.114” and a MAC address of “mac=00–lC–B3–B4–48–95”. U.S. v. Stanley, supra. The networking card was an Apple wireless device, which led Erdely to believe the computer using the private 114 IP address was an Apple computer. U.S. v. Stanley, supra. Neither of Kozikowski’s computers was an Apple computer.

Erdely learned that the computer using the private 114 IP address was using port 6346 to interact with other devices assigned IP addresses. U.S. v. Stanley, supra.  He had seen port 6346 used consistently by persons using the Gnutella network to view and share child pornography.

Erdely decided to use Moocherhunter to locate the computer assigned the 114 IP address. He had received “a few minutes of training” on the use of Moocherhunter and used a free version of the program, which was available on the manufacturer's website. U.S. v. Stanley, supra. According to the opinion, the site described Moocherhunter as a free mobile tracking software tool for the real-time on-the-fly geo-location of wireless moochers, hackers and users of wireless networks for objectionable purposes”.  U.S. v. Stanley, supra.


The program has an “active mode and a passive mode”; Erdely used it in the passive mode.  U.S. v. Stanley, supra. “In the passive mode, the user . . . enters the MAC address of a wireless router that is connected to a wireless device and traces the signal of that wireless device from the wireless router back to its source.” U.S. v. Stanley, supra. Erdely downloaded the “software to his laptop, connected a directional antenna to his laptop, and used a USB wireless card to connect to Kozikowski's wireless router.” U.S. v. Stanley, supra.

Moocherhunter provides a reading that indicates how close the user of the software is to the source of a signal, with 100 being the highest possible reading. Erdely followed the signal from Kozikowski's wireless router and pointed the antenna across the street from his residence, which is directly across the street from Stanley's residence. . . . Stanley's residence is one unit in an apartment complex comprised of six units. . . .


When Erdely pointed the antenna . . . toward the . . . building in which Stanley resided, the meter reading was 67. Erdely . . . walked across the street to the sidewalk in front of the apartment building in which Stanley's unit was located. . . .

When [he] stood on the sidewalk in front of Stanley's residence and pointed the antenna toward the front door . . ., the meter reading was 100. When Erdely pointed the antenna to the left or right of Stanley's residence, the meter reading weakened. Based on the Moocherhunter readings, Erdely determined the signal from the computer assigned the 95 MAC address to connect to Kozikowski's wireless router was emanating from Stanley's residence.

U.S. v. Stanley, supra.

Erdely used the information he had obtained to get a search warrant for Stanley’s residence, which he executed.  U.S. v. Stanley, supra.  Evidence “obtained from the search of Stanley’s home and computer” was used to charge him with possessing child pornography, and was therefore the focus of the motion to suppress noted above.  U.S. v. Stanley, supra.  Stanley apparently argued that the search of his home and computer violated the 4th Amendment because while it was conducted pursuant to a warrant, the warrant was the product of another search that violated the 4th Amendment.  U.S. v. Stanley, supra.  He claimed Erdely’s use of Moocherhunter to track the wireless signal to his home was a 4th Amendment “search.”  U.S. v. Stanley, supra.

The judge began her analysis of Stanley’s argument by noting that it required her to determine whether he “had a legitimate expectation of privacy in the wireless signal he caused to emanate from the computer in his home to Kozikowski's wireless router and the wireless signal he received back from Kozikowski's wireless router in order to connect to the internet.”  U.S. v. Stanley, supra.  As Wikipedia notes, and as I have explained in prior posts, the 4th Amendment bans “unreasonable” searches and to be “reasonable” a “search” must either be conducted pursuant to a warrant or to an exception to the warrant requirement. 

As I’ve also explained in prior posts, a “search” violates a “reasonable expectation of privacy” in a place or thing.  In Katzv. U.S., 389 U.S. 347 (1967), the Supreme Court held that one has a reasonable expectation of privacy in a place or thing if (i) they believe (subjectively) that it is private and (ii) society agrees that their belief is objectively reasonable.  For more on that, check out this prior post.

The judge began her analysis of whether using Moocherhunter to track the wireless signal was a search by citing the Katz test and then pointing out that the Supreme Court “has held that under the 4th Amendment, there is no reasonable expectation of privacy in information voluntarily conveyed to third parties.”  U.S. v. Stanley, supra. 

The case the judge was referencing was the Court’s decision in Smith v. Maryland, 442 U.S. 735 (1979), which I’ve discussed in prior posts.  In Smith, the Court held that a man did not have a 4th Amendment expectation of privacy in the numbers he dialed from his home phone, and which were recorded by a pen register officers had installed on his phone, because he voluntarily conveyed that information to the phone company.  As I’ve noted, the Smith Court found that if someone shares information with another person, they assume the risk that the person will betray them by sharing it with other parties.

The judge in this case essentially found that it was indistinguishable from Smith:

Here, Moocherhunter monitored the strength of a signal that Stanley voluntarily caused to send from his computer to Kozikowski's wireless router and to receive a signal back from the wireless router in order to gain unauthorized access to Kozikowski's internet connection.

In both cases, the party seeking suppression of evidence assumed the risk that information disclosed to a third party may be turned over to the police. Notably, Moocherhunter, like the pen register, did not reveal the contents of the communications; it only revealed that communications were taking place.

U.S. v. Stanley, supra. 

The judge also noted that

[e]ven though that signal was sent from and to the inside of Stanley's home and revealed there was a computer inside of the home, no expectation of privacy existed. By connecting to Kozikowski's wireless router, Stanley exposed his wireless signal to a third party and assumed the risk that the signal would be revealed to the authorities.

Like the defendant in Smith who dialed a telephone number from inside his home, Stanley cannot hide behind sending the signal from inside his home and claim he had a reasonable expectation of privacy in the signal.

U.S. v. Stanley, supra. 

She therefore held that Stanley

did not have a reasonable expectation of privacy in the wireless signal he caused to emanate from his computer to Kozikowski's wireless router or the wireless signal he received from Kozikowski's wireless router in order to connect to the internet. The information logged on that wireless router was accessible to Kozikowski and through his consent, to Erdely.

This information showed the private IP address of Stanley's computer. Stanley, therefore, could have no reasonable expectation of privacy in the signal he was sending to or receiving from Kozikowski's wireless router in order to connect to the internet.

U.S. v. Stanley, supra. 

Finally, she also rejected Stanley’s argument that Erdely’s use of Moocherhunter was a 4th Amendment “search” under the Supreme Court’s decision in Kyllo v. U.S., 533 U.S. 27 (2001).  U.S. v. Stanley, supra. 

As I explained in a prior post, in Kyllo the Supreme Court held that it is a 4th Amendment “search” to use technology that is not in general public usage to obtain information from inside a home that could not otherwise be obtained except by entering the home.  The judge found that Kyllo did not apply because, unlike Kyllo, Stanley voluntarily shared the information at issue with a third party.  U.S. v. Stanley, supra.  

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