SSL/TLS LogJam mitm Security Restriction Bypass Vulnerability (CVE-2015-4000)

Source: Internet
Author: User

SSL/TLS LogJam mitm Security Restriction Bypass Vulnerability (CVE-2015-4000)
SSL/TLS LogJam mitm Security Restriction Bypass Vulnerability (CVE-2015-4000)

Release date:
Updated on:

Affected Systems:

OpenSSL Project OpenSSL < 1.0.2
OpenSSL Project OpenSSL < 1.0.1


Bugtraq id: 74733
CVE (CAN) ID: CVE-2015-4000

TLS is a secure transport layer protocol used to provide confidentiality and data integrity between two communication applications.

TLS 1.2 and earlier versions, which are enabled on the server but not in the DHE_EXPORT password Group enabled on the client, do not correctly forward the DHE_EXPORT selection. Man-in-the-middle attackers replace DHE with DHE_EXPORT and override ClientHello, then, use DHE to replace DHE_EXPORT and overwrite ServerHello (that is, the "Logjam" problem). This vulnerability can be exploited to perform password downgrade attacks.

<* Source: Nadia Heninger
Zakir Durumeric
Karthikeyan Bhargavan
David Adrian
K Paul Zimmermann



Vendor patch:

OpenSSL Project
The OpenSSL Project has released a Security Bulletin (secadv_20150611) and corresponding patches:
Secadv_20150611: OpenSSL Security Advisory [11 Jun 2015]

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