For years, legal wiretapping was straightforward: the officer doing the intercept connected a tape recorder or the like to a single pair of wires. By the 1990s, though, the changing structure of telecommunications — there was no longer just “Ma Bell” to talk to — and new technologies such as ISDN and cellular telephony made executing a wiretap more complicated for law enforcement. Simple technologies would no longer suffice. In response, Congress passed the Communications Assistance for Law Enforcement Act (CALEA), which mandated a standardized lawful intercept interface on all local phone switches. Technology has continued to progress, and in the face of new forms of communication — Skype, voice chat during multi-player online games, many forms of instant messaging, etc.— law enforcement is again experiencing problems. The FBI has called this “Going Dark”: their loss of access to suspects’ communication. According to news reports, they want changes to the wiretap laws to require a CALEA-¬like interface in Internet software.
CALEA, though, has its own issues: it is complex software specifically intended to create a security hole — eavesdropping capability — in the already-¬complex environment of a phone switch. It has unfortunately made wiretapping easier for everyone, not just law enforcement. Congress failed to heed experts’ warnings of the danger posed by this mandated vulnerability, but time has proven the experts right. The so-¬called “Athens Affair,” in which someone used the built-¬in lawful intercept mechanism to listen to the cell phone calls of high Greek officials, including the Prime Minister, is but one example. In an earlier work, we showed why extending CALEA to the Internet would create very serious problems, including the security problems it has visited on the phone system.
In this talk, we explore the viability and implications of an alternative method for addressing law enforcement's need to access communications: legalized hacking of target devices through existing vulnerabilities in end-¬user software and platforms. The FBI already uses this approach on a small scale; we expect that its use will increase, especially as centralized wiretapping capabilities become less viable.
Relying on vulnerabilities and hacking poses a large set of legal and policy questions, some practical and some normative. Among these are:
- Will it create disincentives to patching?
- Will there be a negative effect on innovation? (Lessons from the so-¬called “Crypto Wars” of the 1990s, and, in particular, the debate over export controls on cryptography, are instructive here.)
- Will law enforcement’s participation in vulnerabilities purchasing skew the market?
- Do local and even state law enforcement agencies have the technical sophistication to develop and use exploits? If not, how should this be handled? A larger FBI role?
- Should law enforcement even be participating in a market where many of the sellers and other buyers are themselves criminals?
- What happens if these tools are captured and re-purposed by miscreants?
- Should we sanction otherwise-¬illegal network activity to aid law enforcement?
- Is the probability of success from such an approach too low for it to be useful?
As we will show, though, these issues are indeed challenging. We regard them, on balance, as preferable to adding more complexity and insecurity to online systems.
Steven M. Bellovin is a professor of computer science at Columbia University, where he does research on networks, security, and especially why the two don’t get along, as well as related public policy issues. In his spare professional time, he does some work on the history of cryptography. He joined Columbia in 2005 after many years at Bell Labs and AT&T Labs Research, where he was an AT&T Fellow. He received his Ph.D. in Computer Science from the University of North Carolina at Chapel Hill. While a graduate student, he helped create Netnews; for this, he and the other perpetrators were given the 1995 Usenix Lifetime Achievement Award (The Flame). Bellovin has served as Chief Technologist of the Federal Trade Commission. He is a member of the National Academy of Engineering and is serving on the Computer Science and Telecommunications Board of the National Academies, the Department of Homeland Security’s Science and Technology Advisory Committee, and the Technical Guidelines Development Committee of the Election Assistance Commission. He is a co-author of Firewalls and Internet Security: Repelling the Wily Hacker, and holds a number of patents on cryptographic and network protocols. He received the 2007 NIST/NSA National Computer Systems Security Award.
Reception to follow in 301 Coordinated Science Laboratory.