Many modern communications systems use Orthogonal Frequency Division Modulation (OFDM). These systems need to synchronize the receiver and equalize the channel to achieve good performance. The algorithms used to perform timing synchronization and channel estimation/equalization typically are designed without considering whether an adversarial signal could disrupt these subsystems. In typical scenarios, a jammer would not have reliable (or any) knowledge of the channels filtering the target or jamming signals. Thus, in this paper, we consider attack strategies that do not require channel knowledge. We study the efficiency of several jamming strategies targeting each subsystem as measured by the peak and average signal-to-jamming ratio (SJR) required to achieve signal denial for each method and find that jamming the timing can be substantially more efficient than other jamming strategies. We also discuss modifications to the jamming strategies that might be necessary for real-world operation.