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Microsoft Admits Windows Users Are Vulnerable to FREAK Attacks

Several days after the new SSL/TLS flaw is discovered, Microsoft has realized that its users are also at risk.

FREAK attack

When the FREAK SSL and TLS encryption security vulnerability was first disclosed earlier this week, only Apple's Safari and Google's Android browsers were considered to be at risk. The risk has expanded, and it now includes Microsoft.

When the FREAK (Factoring attack on RSA-EXPORT Keys) bug news first broke on March 3, I did my due diligence and contacted both Microsoft and Mozilla to find out from all the major browser vendors what the risk was to their respective users. Richard Barnes, cryptographic engineering manager at Mozilla, told me that Mozilla software, including Firefox, is not vulnerable to the FREAK attack.

My sources at Microsoft initially told me that the issue was reported as only impacting Apple and Google. Sources also informed me that Microsoft was investigating the issue. I responded that given the nature of the issue, I suspected that Microsoft Windows users might also be at risk. As it turns out, I was right.

Microsoft Security Advisory 3046015 on the FREAK issue was published on March 5.

"Our investigation has verified that the vulnerability could allow an attacker to force the downgrading of the cipher suites used in an SSL/TLS [Secure Sockets Layer/Transport Layer Security] connection on a Windows client system," Microsoft's advisory warns. "The vulnerability facilitates exploitation of the publicly disclosed FREAK technique, which is an industry-wide issue that is not specific to Windows operating systems."

Microsoft's advisory also noted that the vulnerability is caused by an issue in the TLS state machine inside of Schannel, which is the security library in Windows that provides SSL and TLS. The issue impacts all currently supported releases of Windows.

The FREAK vulnerability is also identified as CVE-2015-0204 and technically is a cryptographic weakness in export-grade cryptography. Export-grade cryptography is a class of weaker cipher suites that were intended to be used outside of the U.S. The FREAK attack is able to downgrade a server's SSL/TLS connection to use the weaker export-grade ciphers, which could potentially enable an attacker to decrypt the encrypted communications.

Somewhat ironically, the FREAK flaw was first reported by the miTLS research effort, which is a joint project of INRIA and Microsoft Research. That's right, Microsoft Research had some involvement in the initial FREAK research, but did not apparently make the connection to Microsoft's Windows operating system.

Although there is risk from FREAK, Microsoft's advisory provides a workaround to protect Windows Vista and later systems. That said, there is no workaround for Windows Server 2003, which is still a supported Microsoft operating system.

"The cipher management architecture on Windows Server 2003 does not allow for the enabling or disabling of individual ciphers," Microsoft's advisory states.

The bottom line here though is that Microsoft has not yet seen any FREAK attacks in the wild against Windows, though that doesn't mean that attacks won't emerge in the days ahead. Microsoft has also noted that it could potentially issue an out-of-band security update for FREAK or an update as part of its normal monthly patching process.

Sean Michael Kerner is a senior editor at eWEEK and Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.