Preventing DROWN Attack (March 2, 2016)

On March 1st 2016, OpenSSL released patches that disable the SSLv2 protocol by default, as well as removing SSLv2 EXPORT ciphers.

A cross-protocol attack was discovered that could lead to decryption of TLS sessions by using a server supporting SSLv2 and EXPORT cipher suites as a Bleichenbacher RSA padding oracle. Note that traffic between clients and non-vulnerable servers can be decrypted provided another server supporting SSLv2 and EXPORT ciphers (even with a different protocol such as SMTP, IMAP or POP) shares the RSA keys of the non-vulnerable server. This vulnerability is known as DROWN.

The vulnerability is referred by CVE as CVE-2016-0800.

Dell SonicWALL customers are encouraged to enable the following IPS signature to detect and block SSLv2 traffic:

• 5160 SSLv2.0 Client Hello

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The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.