Structuring Protocol Implementations to Protect Sensitive Data

Date Added: Jun 2010
Format: PDF

In a bid to limit the harm caused by ubiquitous remotely exploitable software vulnerabilities, the computer systems security community has proposed primitives to allow execution of application code with reduced privilege. In this paper, the authors identify and address the vital and largely unexamined problem of how to structure implementations of cryptographic protocols to protect sensitive data despite exploits. As evidence that this problem is poorly understood, they first identify two attacks that lead to disclosure of sensitive data in two published state-of the-art designs for exploit-resistant cryptographic protocol implementations: privilege-separated OpenSSH, and the HiStar/DStar DIFC-based SSL web server. They then describe how to structure protocol implementations on UNIX- and DIFC-based systems to defend against these two attacks and protect sensitive information from disclosure.