The PDF document holds a single paged scan of an internally distributed mail from German telecommunications company T-Systems (Deutsche Telekom), revealing over two dozen secret IP address ranges in use by the German intelligence service Bundesnachrichtendienst (BND). Independent evidence shows that the claim is almost certainly true and the document itself has been verified by a demand letter from T-systems to Wikileaks.

The 32nd episode of The Silver Bullet Security Podcast features founder and Chief Technology Officer of WhiteHat Security, Jeremiah Grossman. Gary and Jeremiah discuss clickjacking, cross-site request forgery, why 50% of web problems can’t be discovered reliably automatically, and which conferences Jeremiah most enjoyed on his 2008 world tour.

• Jeremiah Grossman
• Clickjacking
• Adobe 0-day Browser Exploit
• Cross-Site Request Forgeries: Exploitation and Prevention [PDF]
• Web Spoofing: An Internet Con Game by Edward W. Felten, Dirk Balfanz, Drew Dean, and Dan S. Wallach.
• Web application scan-o-meter
• The “Wall of Fame”

District Court Holds that Running Hash Values on Computer Is A Search: The case is United States v. Crist, 2008 WL 4682806 (M.D.Pa. October 22 2008) (Kane, C.J.). It's a child pornography case involving a warrantless search that raises a very interesting and important question of first impression: Is running a hash a Fourth Amendment search? (For background on what a "hash" is and why it matters, see here).

First, the facts. Crist is behind on his rent payments, and his landlord starts to evict him by hiring Sell to remove Crist's belongings and throw them away. Sell comes a cross Crist's computer, and he hands over the computer to his friend Hipple who he knows is looking for a computer. Hipple starts to look through the files, and he comes across child pornography: Hipple freaks out and calls the police. The police then conduct a warrantless forensic examination of the computer:

In the forensic examination, Agent Buckwash used the following procedure. First, Agent Buckwash created an "MD5 hash value" of Crist's hard drive. An MD5 hash value is a unique alphanumeric representation of the data, a sort of "fingerprint" or "digital DNA." When creating the hash value, Agent Buckwash used a "software write protect" in order to ensure that "nothing can be written to that hard drive." Supp. Tr. 88. Next, he ran a virus scan, during which he identified three relatively innocuous viruses. After that, he created an "image," or exact copy, of all the data on Crist's hard drive.

Agent Buckwash then opened up the image (not the actual hard drive) in a software program called EnCase, which is the principal tool in the analysis. He explained that EnCase does not access the hard drive in the traditional manner, i.e., through the computer's operating system. Rather, EnCase "reads the hard drive itself." Supp. Tr. 102. In other words, it reads every file-bit by bit, cluster by cluster-and creates a index of the files contained on the hard drive. EnCase can, therefore, bypass user-defined passwords, "break down complex file structures for examination," and recover "deleted" files as long as those files have not been written over. Supp. Tr. 102-03.

Once in EnCase, Agent Buckwash ran a "hash value and signature analysis on all of the files on the hard drive." Supp. Tr. 89. In doing so, he was able to "ingerprint" each file in the computer. Once he generated hash values of the files, he compared those hash values to the hash values of files that are known or suspected to contain child pornography. Agent Buckwash discovered five videos containing known child pornography. Attachment 5. He discovered 171 videos containing suspected child pornography.

One of the interesting questions here is whether the search that resulted was within the scope of Hipple's private search; different courts have approached this question differently. But for now the most interesting question is whether running the hash was a Fourth Amendment search. The Court concluded that it was, and that the evidence of child pornography discovered had to be suppressed:

The Government argues that no search occurred in running the EnCase program because the agents "didn't look at any files, they simply accessed the computer." 2d Supp. Tr. 16. The Court rejects this view and finds that the "running of hash values" is a search protected by the Fourth Amendment.

Computers are composed of many compartments, among them a "hard drive," which in turn is composed of many "platters," or disks. To derive the hash values of Crist's computer, the Government physically removed the hard drive from the computer, created a duplicate image of the hard drive without physically invading it, and applied the EnCase program to each compartment, disk, file, folder, and bit.2d Supp. Tr. 18-19. By subjecting the entire computer to a hash value analysis-every file, internet history, picture, and "buddy list" became available for Government review. Such examination constitutes a search.

I think this is generally a correct result: See my article Searches and Seizures in a Digital World, 119 Harv. L. Rev. 531 (2005), for the details. Still, given the lack of analysis here it's somewhat hard to know what to make of the decision. Which stage was the search — the creating the duplicate? The running of the hash? It's not really clear. I don't think it matters very much to this case, because the agent who got the positive hit on the hashes didn't then get a warrant. Instead, he immediately switched over to the EnCase "gallery view" function to see the images, which seems to be to be undoudtedly a search. Still, it's a really interesting question.

No longer are OS vendors and other large infrastructure technology providers the main source of vulnerabilities. It’s the thousands of applications, produced by thousands of software vendors, that make up this huge 3rd wave. ISS reported that in 2007 that the top five sources of vulnerabilities: Microsoft, Apple, Oracle, IBM, and Cisco, had dropped to supplying us with only 13.6% of our vulnerabilities. 86.4% came from the other thousands of software vendors that supply our computers with a seemingly unending supply of vulnerabilities for attackers to exploit.

In a recent report Microsoft has congratulated itself on doing a good job securing Windows. And by all accounts they have done a good job. But then they state this:

“Unless software development practices change throughout the industry, any improvements in the security of Windows would be meaningless.”

Whoa. Millions of dollars spent on securing the most prevalent piece of software and it could be meaningless? Yes, it’s true. Since attackers typically only need one vulnerability, if it isn’t in the network, and it isn’t in the host configuration, and it isn’t in the OS, they will happily exploit a vulnerability in an application.

At every shift of exploit target the problem has gotten more difficult to solve. Networks had choke points and could be centrally managed. It took a while but eventually host configurations became centrally managed and automated tools could scan configurations. Although OSes were huge and complex beasts with 10’s of millions of lines of code, with enough effort, their vulnerabilities have been largely tamed as Microsoft’s Windows and the Linux kernel track record shows. This was a very substantial, over five year effort, which used some of the most talented security people anywhere.
But now what to do? Instead of a few OSes we now have thousands of applications with vulnerabilities. As Microsoft found out, the attackers don’t go away, they just move on to the next incrementally less juicy vulnerability. In the world of exploits that typically means the vulnerability with the next smallest target population.

Attackers have started with the common client applications that can be found on almost every machine: Acrobat, Flash, RealPlayer, Quicktime, popular antivirus software. And they will continue down the popularity slope until they get to application populations down in the thousands which is getting to fairly small software vendors. Attackers can do this because they can bundle many vulnerabilities together, exploiting the statistical fact that you must have some vulnerable software installed. Compromised web sites have been found attacking visitors with over ten client side exploits preying on multiple versions of vulnerable client software.

The solution to this problem is all software must be written securely, not just the software from the big guys. Small vendors think they aren’t a target just like home users used to think they weren’t a target. People thought, “Why would someone want to attack my home computer?” Then they realized they did home banking, or had a fast internet connection that could be used for DDoS attacks or sending spam. All software vendors need to get the same wakeup call. Attackers don’t want to find a vulnerability in your software to make you look bad. They want any vulnerability. If the population of your software is small they will just bundle your vulnerability together with others in an exploit pack. The days of the average software vendor not having to worry about application security are officially over.