| Description: | Summary:
The remote host is missing an update for the Debian 'openssl' package(s) announced via the DLA-1701-1 advisory.
Vulnerability Insight:
Juraj Somorovsky, Robert Merget and Nimrod Aviram discovered a padding oracle attack in OpenSSL.
If an application encounters a fatal protocol error and then calls SSL_shutdown() twice (once to send a close_notify, and once to receive one) then OpenSSL can respond differently to the calling application if a 0 byte record is received with invalid padding compared to if a 0 byte record is received with an invalid MAC. If the application then behaves differently based on that in a way that is detectable to the remote peer, then this amounts to a padding oracle that could be used to decrypt data.
In order for this to be exploitable 'non-stitched' ciphersuites must be in use. Stitched ciphersuites are optimised implementations of certain commonly used ciphersuites. Also the application must call SSL_shutdown() twice even if a protocol error has occurred (applications should not do this but some do anyway). AEAD ciphersuites are not impacted.
For Debian 8 Jessie, this problem has been fixed in version 1.0.1t-1+deb8u11.
We recommend that you upgrade your openssl packages.
Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: [link moved to references]
Affected Software/OS:
'openssl' package(s) on Debian 8.
Solution:
Please install the updated package(s).
CVSS Score:
4.3
CVSS Vector:
AV:N/AC:M/Au:N/C:P/I:N/A:N
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