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Diffie-Hellman Key Exchange "Logjam" Vulnerability

Last Update Date: 22 May 2015 12:14 Release Date: 22 May 2015 3943 Views

RISK: Medium Risk

TYPE: Security software and application - Security Software & Appliance

TYPE: Security Software & Appliance

A vulnerability has been identified in Diffie-Hellman Key Exchange (DH). The vulnerability allows attackers to intercept protocols that rely on DH and force them to use ‘export-grade’ cryptography, which can then be decrypted or altered.


Impact

  • Information Disclosure

System / Technologies affected

  • Server and client applications use export grade ciphers (EC).

Solutions

 Before installation of the software, please visit the software manufacturer web-site for more details.

  • For clients:
    • Please note the vendor releasing the patch. Currently, you can check whether your browser is affected by visiting this webpage: https://weakdh.org/
  • For servers:
    • If you have a web or mail server, you should disable support for export cipher suites and generate a unique 2048-bit Diffie-Hellman group. You can refer to this guide for details: https://weakdh.org/sysadmin.html
    • If you use SSH, you should upgrade both your server and client installations to the most recent version of OpenSSH, which prefers Elliptic-Curve Diffie-Hellman Key Exchange.

 


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Source


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