Ubuntu Security Notice USN-2959-1

3rd May, 2016

openssl vulnerabilities

A security issue affects these releases of Ubuntu and its
derivatives:

• Ubuntu 16.04 LTS
• Ubuntu 15.10
• Ubuntu 14.04 LTS
• Ubuntu 12.04 LTS

Summary

Several security issues were fixed in OpenSSL.

Software description

• openssl
  – Secure Socket Layer (SSL) cryptographic library and tools

Details

Huzaifa Sidhpurwala, Hanno Böck, and David Benjamin discovered that OpenSSL
incorrectly handled memory when decoding ASN.1 structures. A remote
attacker could use this issue to cause OpenSSL to crash, resulting in a
denial of service, or possibly execute arbitrary code. (CVE-2016-2108)

Juraj Somorovsky discovered that OpenSSL incorrectly performed padding when
the connection uses the AES CBC cipher and the server supports AES-NI. A
remote attacker could possibly use this issue to perform a padding oracle
attack and decrypt traffic. (CVE-2016-2107)

Guido Vranken discovered that OpenSSL incorrectly handled large amounts of
input data to the EVP_EncodeUpdate() function. A remote attacker could use
this issue to cause OpenSSL to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2016-2105)

Guido Vranken discovered that OpenSSL incorrectly handled large amounts of
input data to the EVP_EncryptUpdate() function. A remote attacker could use
this issue to cause OpenSSL to crash, resulting in a denial of service, or
possibly execute arbitrary code. (CVE-2016-2106)

Brian Carpenter discovered that OpenSSL incorrectly handled memory when
ASN.1 data is read from a BIO. A remote attacker could possibly use this
issue to cause memory consumption, resulting in a denial of service.
(CVE-2016-2109)

As a security improvement, this update also modifies OpenSSL behaviour to
reject DH key sizes below 1024 bits, preventing a possible downgrade
attack.

Update instructions

The problem can be corrected by updating your system to the following
package version:

Ubuntu 16.04 LTS:

libssl1.0.0

1.0.2g-1ubuntu4.1

Ubuntu 15.10:

libssl1.0.0

1.0.2d-0ubuntu1.5

Ubuntu 14.04 LTS:

libssl1.0.0

1.0.1f-1ubuntu2.19

Ubuntu 12.04 LTS:

libssl1.0.0

1.0.1-4ubuntu5.36

To update your system, please follow these instructions:
https://wiki.ubuntu.com/Security/Upgrades.

After a standard system update you need to reboot your computer to make
all the necessary changes.

References

CVE-2016-2105,

CVE-2016-2106,

CVE-2016-2107,

CVE-2016-2108,

CVE-2016-2109