Collusive Attacks Against Software Watermarks

Software fingerprinting is a technique to protect software by embedding unique watermarks in different copies of the same program. This makes individual copies of the program easier to trace. However, fingerprinted software is susceptible to collusive attacks if an attacker has access to two or more fingerprinted versions of the same program. We present the first framework for performing collusive attacks against fingerprinted software. In this paper, we describe two static collusive attacks against programs fingerprinted with different instances of the well-known Collberg-Thomborson (CT) watermark. We also describe a promising novel type of collusive attack we call a "dynamic collusive attack". Our preliminary experiments show that such attacks are highly effective at locating CT watermarks