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My company uses Qualys to scan for vulnerabilities in our apps. I received a report with four vulnerabilities (related to SSLv3 and ciphers), and I could google each one and land on page from Qualys that specifies a manual command I could run to verify if I passed it or not, after making changes to my configuration.

For example, to verify the passing of QID 38143 - SSL Server Allows Cleartext Communication Vulnerability:

openssl s_client -connect TARGET_IP:443 -cipher eNULL

However, I could find no such page for QID 42366 - SSLv3.0/TLSv1.0 Protocol Weak CBC Mode Server Side Vulnerability (BEAST).

How can I verify if I pass this Qualys QID?

Matthew Moisen
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1 Answers1

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BEAST is caused by a flaw in the protocol, not by a bug in the implementation.

Every server that supports TLS 1.0 with a CBC cipher suite is vulnerable to BEAST. Because the only other way to use TLS 1.0 is with RC4, this means that if BEAST is a concern, you can't allow TLS 1.0.

Most browsers mitigate BEAST using the 1/(n-1) split, so people keep supporting TLS 1.0.

A way to check whether your server is vulnerable:

openssl s_client -connect qualys.jive-mobile.com:443 -tls1 -cipher 'AES:CAMELLIA:SEED:3DES:DES'

Wikipedia

Qualys

Z.T.
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  • Hi ZT, thanks. If I can connect successfully, that means I am vulnerable, correct? – Matthew Moisen Oct 13 '15 at 22:02
  • @MatthewMoisen Yes. – Z.T. Oct 13 '15 at 22:17
  • For completeness, SSL3 CBC is also vulnerable to BEAST, but it is so much more vulnerable to POODLE many (most?) people are dropping SSL3 while as you say keeping TLS1.0 with split-1/n to block BEAST. Also, if a server accepts single-DES in *any* protocol that's bad, and similarly for any anonymous keyexchange (which openssl normally disables by default but your cipherstring enables). – dave_thompson_085 Oct 14 '15 at 06:18