Retiring an email server with sensitive data on it? Learn some lessons from Clinton

In the latest chapter in the ongoing saga concerning Hillary Clinton’s use of a private email server for herself and some of her staff during her tenure as Secretary of State, the Washington Post reported that the IT services company Clinton hired to manage the server after she left the State Department has “no knowledge of the server being wiped” despite suggestions by Clinton and her attorney that the contents of the server had been permanently erased. Much has been made of the important technical distinction between deleting files or data on a computer and wiping the hard drive or other storage on a computer. As many people aside from Clinton seem to be aware, merely deleting files does not actually erase or remove them, but simply makes the storage space they take up available to be overwritten in the future. Depending on the use of a computer afterward, deleted data can remain in storage and may be retrievable through simple “undelete” commands or through forensic analysis. In contrast, wiping is meant to permanently remove data from storage by overwriting the space it occupied with random data; data erasure methods used by many government and private sector entities overwrites the data multiple times to better ensure that the original data cannot be retrieved or pieced back together.

Those who have been following the historical accounts of the Clinton email server may recall that there have actually been two servers in use – the first was set up and maintained at the Clintons’ home in Chappaqua, New York, while the second was put into service when Clinton moved her email system management to Platte River Networks. (Historical analysis of DNS records associated with suggest the switch to a third-party host may have occurred in 2010 rather than 2013). If tasks like server wiping were left to the Clinton team and not handled by Platte River, then it seems at least possible that the original server may not have been properly wiped when the data on it was transferred to the new server. According to Post reports, Platte River took possession of the original server and stored it at a data center facility in New Jersey until it handed the server over to the FBI at Clinton’s request. News accounts of the Platte River relationship explain that emails covering Clinton’s entire service as Secretary of State were on the original server and were migrated to a new server. The contents of the second server were subsequently copied to removable
media in 2014 and either deleted or removed from that server. The latest details suggest that neither of the two servers may have been wiped, but since they ostensibly contain the same data (at least from the 2009-2013 time period when Clinton was at State), if either server was not sanitized then many if not all of Clinton’s emails could be retrieved. Because the server and its data were migrated to a new server in 2013, there is little practical value in keeping the original server, especially if its contents had been securely erased. Clinton’s team should now feel some measure of relief that they did not dispose of the the original server if it turns out that is wasn’t wiped.

From a security best practice standpoint, if in fact the Clinton email server was not wiped as Clinton and her team apparently intended, then this failure to permanently remove Clinton’s personal emails and any other data she didn’t wish to share with government investigators provides another good example of operational security controls that would presumably be in place with a government-managed email server that were lacking in Clinton’s private setup. The National Institute of Standards and Technology (NIST) refers to data wiping by the more formal term “media sanitization” and requires the practice for all information contained in federal information systems, regardless of the sensitivity level of the data. While it is certainly likely that at least some public and private sector organizations fail to perform data wiping on servers, computer workstations, and other hardware that includes writeable storage, it is a very common security practice among organizational and individual computer users.

The possibility that Clinton’s email hasn’t been, as her attorney and spokespeople have asserted, completely removed from the server may make it a bit harder for her critics to argue that Clinton’s deliberate action to wipe the server is a sign that she has something to hide, although it may be that she and her staff intended to permanently remove the emails and just didn’t have the technical knowledge to do it properly. This is troubling in part because of the implication that – notwithstanding the security skills of the State Department staffer the Clintons privately paid to manage the server they kept at their home – routine security practices may not have been put in place. When the use of the private server became widely known, several sources used publicly available information about the domain and the Microsoft Exchange server used to provide email services for Clinton and others. It’s hard to know whether even basic security recommendations from Microsoft were followed, but some have pointed to server and operating system fingerprinting results indicating the server was running Windows Server 2008 (and had not been upgraded to the more secure 2012 version). Aside from potential vulnerabilities associated with the OS and the Exchange 2010 software that may or may not have been patched, the server was also apparently configured to allow remote connections both via Outlook Web Access and an SSL VPN, both of which used self-signed digital certificates to establish secure connections. It makes sense that Clinton would want and need access to the server from anywhere, although a more secure approach would limit connections to Outlook email clients or ActiveSync-enabled devices. Regardless of how well (or poorly) the server was secured while it was operational, the steps taken to secure the data once the server was no longer in use provide a good example of what not to do.

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