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Vulnerability of Bouncy Castle: MD5 allowed in TLS 1.2

Synthesis of the vulnerability 

An attacker can create a collision with a weak algorithm such as MD5 in a TLS 1.2 session of Bouncy Castle, in order to capture data belonging to this session.
Impacted products: Bouncy Castle JCE, openSUSE, openSUSE Leap, SUSE Linux Enterprise Desktop, SLES, Synology DS***, Synology RS***.
Severity of this bulletin: 1/4.
Creation date: 30/12/2015.
Références of this threat: CVE-2015-7575, openSUSE-SU-2016:0605-1, SLOTH, SUSE-SU-2016:0256-1, VIGILANCE-VUL-18615.

Description of the vulnerability 

The Bouncy Castle library implements TLS version 1.2.

However, Bouncy Castle does not check if the algorithm used in the DigitallySigned structure is part of the accepted algorithms indicated in the signature_algorithms extension or the CertificateRequest message.

This vulnerability has the same origin than VIGILANCE-VUL-18586.

An attacker can therefore create a collision with a weak algorithm such as MD5 in a TLS 1.2 session of Bouncy Castle, in order to capture data belonging to this session.
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This computer weakness alert impacts software or systems such as Bouncy Castle JCE, openSUSE, openSUSE Leap, SUSE Linux Enterprise Desktop, SLES, Synology DS***, Synology RS***.

Our Vigil@nce team determined that the severity of this weakness note is low.

The trust level is of type confirmed by the editor, with an origin of internet client.

An attacker with a expert ability can exploit this weakness bulletin.

Solutions for this threat 

Bouncy Castle: version 1.54.
The version 1.54 is fixed:
  http://www.bouncycastle.org/latest_releases.html

openSUSE: new bouncycastle packages.
New packages are available:
  openSUSE 13.2: bouncycastle 1.54-13.6.1
  openSUSE Leap 42.1: bouncycastle 1.54-19.1

SUSE LE 12: new java-1_8_0-openjdk packages.
New packages are available:
  SUSE LE 12 SP1: java-1_8_0-openjdk 1.8.0.72-3.2

Synology DS, RS: version 5.2-5644 Update 3.
The version 5.2-5644 Update 3 is fixed:
  https://www.synology.com
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