Ubuntu Security Notice 1898-1 - The TLS protocol 1.2 and earlier can encrypt compressed data without properly obfuscating the length of the unencrypted data, which allows man-in-the-middle attackers to obtain plaintext content by observing length differences during a series of guesses in which a provided string potentially matches an unknown string in encrypted and compressed traffic. This is known as a CRIME attack in HTTP. Other protocols layered on top of TLS may also make these attacks practical. This update disables compression for all programs using SSL and TLS provided by the OpenSSL library. To re-enable compression for programs that need compression to communicate with legacy services, define the variable OPENSSL_DEFAULT_ZLIB in the program's environment. Various other issues were also addressed.
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==========================================================================Ubuntu Security Notice USN-1898-1
July 04, 2013
openssl vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 13.04
- Ubuntu 12.10
- Ubuntu 12.04 LTS
- Ubuntu 10.04 LTS
Summary:
Applications could be made to expose sensitive information over the
network.
Software Description:
- openssl: Secure Socket Layer (SSL) cryptographic library and tools
Details:
The TLS protocol 1.2 and earlier can encrypt compressed data without
properly obfuscating the length of the unencrypted data, which allows
man-in-the-middle attackers to obtain plaintext content by observing
length differences during a series of guesses in which a provided string
potentially matches an unknown string in encrypted and compressed traffic.
This is known as a CRIME attack in HTTP. Other protocols layered on top of
TLS may also make these attacks practical.
This update disables compression for all programs using SSL and TLS
provided by the OpenSSL library. To re-enable compression for programs
that need compression to communicate with legacy services, define the
variable OPENSSL_DEFAULT_ZLIB in the program's environment.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 13.04:
libssl1.0.0 1.0.1c-4ubuntu8.1
Ubuntu 12.10:
libssl1.0.0 1.0.1c-3ubuntu2.5
Ubuntu 12.04 LTS:
libssl1.0.0 1.0.1-4ubuntu5.10
Ubuntu 10.04 LTS:
libssl0.9.8 0.9.8k-7ubuntu8.15
In general, a standard system update will make all the necessary changes.
References:
http://www.ubuntu.com/usn/usn-1898-1
CVE-2012-4929
Package Information:
https://launchpad.net/ubuntu/+source/openssl/1.0.1c-4ubuntu8.1
https://launchpad.net/ubuntu/+source/openssl/1.0.1c-3ubuntu2.5
https://launchpad.net/ubuntu/+source/openssl/1.0.1-4ubuntu5.10
https://launchpad.net/ubuntu/+source/openssl/0.9.8k-7ubuntu8.15