Quite an interesting read. Summary? Silk Road used a pair of nginx servers, one as front-end, one as back-end. The server images (captured forensically) show that the then-in-place configuration made it impossible for the FBI agent to do what he claims, that is, connect to the back-end by using the server's IP address (the allow/deny settings forbade this). The log files on the servers lack entries to support FBI claims.

Furthermore, FBI agents describe using other techniques to obtain information, e.g., fuzzing and packet sniffing. Not only do server logs NOT contain any evidence of this, but the agents did not preserve any evidence of their packet sniffing activities, despite having training in forensic investigation techniques and claiming expertise in these areas.

While it is possible that there were bugs in either the Ubuntu 12.04 hosts or the nginx servers themselves that would have allowed these activities to occur, unlogged, I suspect it would now be up to the prosecution to establish reasonable grounds for believing this to be the case. Likewise, while it is possible that the handful of lines of log pertaining to FBI activities might have been removed from the several million (yes, you read that correctly) lines of log later captured in forensic image, that does strain credulity; again I suspect the prosecution would have to establish that, somehow.

I've no particular interest in this case or in Silk Road, but I cannot help but conclude that the lawyer filing this brief just seriously schooled the FBI.