Another Vulnerability Caused by State Meddling

In March a security vulnerability, given the fancy marketing name FREAK, was discovered. FREAK was notable because it was caused by government meddling in computer security. Due to cryptography export restrictions quality cryptographic algorithms were not allowed to be put into widespread use, at least legally, and many legacy systems were built around weak algorithms. FREAK may be behind us but a new vulnerability was just discovered:

Tens of thousands of HTTPS-protected websites, mail servers, and other widely used Internet services are vulnerable to a new attack that lets eavesdroppers read and modify data passing through encrypted connections, a team of computer scientists has found.

The vulnerability affects an estimated 8.4 percent of the top one million websites and a slightly bigger percentage of mail servers populating the IPv4 address space, the researchers said. The threat stems from a flaw in the transport layer security protocol that websites and mail servers use to establish encrypted connections with end users. The new attack, which its creators have dubbed Logjam, can be exploited against a subset of servers that support the widely used Diffie-Hellman key exchange, which allows two parties that have never met before to negotiate a secret key even though they’re communicating over an unsecured, public channel.

The weakness is the result of export restrictions the US government mandated in the 1990s on US developers who wanted their software to be used abroad. The regime was established by the Clinton administration so the FBI and other agencies could break the encryption used by foreign entities. Attackers with the ability to monitor the connection between an end user and a Diffie-Hellman-enabled server that supports the export cipher can inject a special payload into the traffic that downgrades encrypted connections to use extremely weak 512-bit key material. Using precomputed data prepared ahead of time, the attackers can then deduce the encryption key negotiated between the two parties.

We’ll likely be dealing with the consequences of those export restrictions for some time to come. The only upside to this is that it is a reminder of what happens when the government meddles in security for its own purposes. Cryptography export restrictions were put in place because the United States government feared it would be unable to spy on foreign entities (and, as it turns out, domestic entities). Now the government, operating under similar concerns for its ability to spy, is discussing mandating the inclusion of back doors in systems that use strong cryptography. If this happens and developers actually comply we’ll have a repeat of what we’re dealing with today. Security vulnerabilities will arise from government mandated cryptography weaknesses that will put the masses at risk.

Whenever the government wishes the involve itself in something that only appropriate answer for the people to give is a loud “No!” This is especially true when it comes to security because the government has a direct interest in ensuring that each and every one of us is vulnerable to its surveillance apparatus.