UBUNTU-CVE-2015-4000

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    UBUNTU-CVE-2015-4000

    Published: 20 May 2015Last Modified: 29 May 2026
    Upstream:
    CVE-2015-4000
    Aliases:
    USN-2624-1
    USN-2625-1
    USN-2639-1

    Summary:

    Details: The TLS protocol 1.2 and earlier, when a DHE_EXPORT ciphersuite is enabled on a server but not on a client, does not properly convey a DHE_EXPORT choice, which allows man-in-the-middle attackers to conduct cipher-downgrade attacks by rewriting a ClientHello with DHE replaced by DHE_EXPORT and then rewriting a ServerHello with DHE_EXPORT replaced by DHE, aka the "Logjam" issue.

    References: https://ubuntu.com/security/CVE-2015-4000, https://weakdh.org/imperfect-forward-secrecy.pdf, https://weakdh.org/, https://nohats.ca/wordpress/blog/2015/05/20/weakdh-and-ike-ipsec/, https://www.openssl.org/blog/blog/2015/05/20/logjam-freak-upcoming-changes/, http://lists.gnutls.org/pipermail/gnutls-devel/2015-May/007597.html, https://access.redhat.com/articles/1456263, https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/LogJam, https://ubuntu.com/security/notices/USN-2624-1, https://ubuntu.com/security/notices/USN-2625-1, https://ubuntu.com/security/notices/USN-2639-1, https://ubuntu.com/security/notices/USN-2656-1, https://ubuntu.com/security/notices/USN-2656-2, https://ubuntu.com/security/notices/USN-2673-1, https://ubuntu.com/security/notices/USN-2696-1, https://ubuntu.com/security/notices/USN-2706-1, https://www.cve.org/CVERecord?id=CVE-2015-4000

    Affected packages

    Package

    Name: firefox

    Purl: pkg:deb/ubuntu/firefox?arch=source&distro=trusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -39.0+build5-0ubuntu0.14.04.1

    Affected versions

    24.0+build1-0ubuntu1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2015-4000 | CVE-DB