Ubuntu Security Notice 2912-1 - Mariusz Ziulek discovered that libssh incorrectly handled certain packets. A remote attacker could possibly use this issue to cause libssh to crash, resulting in a denial of service. Aris Adamantiadis discovered that libssh incorrectly generated ephemeral secret keys of 128 bits instead of the recommended 1024 or 2048 bits when using the diffie-hellman-group1 and diffie-hellman-group14 methods. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to view sensitive information. Various other issues were also addressed.
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Ubuntu Security Notice USN-2912-1
February 23, 2016
libssh vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 15.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS
Summary:
Several security issues were fixed in libssh.
Software Description:
- libssh: A tiny C SSH library
Details:
Mariusz Ziulek discovered that libssh incorrectly handled certain packets.
A remote attacker could possibly use this issue to cause libssh to crash,
resulting in a denial of service.
(CVE-2015-3146)
Aris Adamantiadis discovered that libssh incorrectly generated ephemeral
secret keys of 128 bits instead of the recommended 1024 or 2048 bits when
using the diffie-hellman-group1 and diffie-hellman-group14 methods. If a
remote attacker were able to perform a man-in-the-middle attack, this flaw
could be exploited to view sensitive information. (CVE-2016-0739)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 15.10:
libssh-4 0.6.3-3ubuntu3.2
Ubuntu 14.04 LTS:
libssh-4 0.6.1-0ubuntu3.3
Ubuntu 12.04 LTS:
libssh-4 0.5.2-1ubuntu0.12.04.6
In general, a standard system update will make all the necessary changes.
References:
http://www.ubuntu.com/usn/usn-2912-1
CVE-2015-3146, CVE-2016-0739
Package Information:
https://launchpad.net/ubuntu/+source/libssh/0.6.3-3ubuntu3.2
https://launchpad.net/ubuntu/+source/libssh/0.6.1-0ubuntu3.3
https://launchpad.net/ubuntu/+source/libssh/0.5.2-1ubuntu0.12.04.6