NetBSD TLS Diffie-Hellman Export Cipher Downgrade Attack Lets Remote Users Decrypt Connections
|
|
SecurityTracker Alert ID: 1033341 |
|
SecurityTracker URL: http://securitytracker.com/id/1033341
|
|
CVE Reference:
CVE-2015-4000
(Links to External Site)
|
Date: Aug 21 2015
|
Impact:
Modification of authentication information
|
Fix Available: Yes Vendor Confirmed: Yes
|
Version(s): 5.1 - 5.1.4, 5.2 - 5.2.2, 6.0 - 6.0.6, 6.1 - 6.1.5
|
Description:
A vulnerability was reported in NetBSD. A remote user may be able to decrypt TLS connections in certain situations.
A remote user that can conduct a man-in-the-middle attack can cause the target system to downgrade the Diffie-Hellman algorithm to 512-bit export-grade cryptography. The remote user may then be able to decrypt the connection.
This vulnerability resides in the TLS protocol and not in the specific TLS implementation, but the vulnerability is exposed because the target system supports export-grade ciphers.
This attack is known as the "Logjam" attack.
The original advisory is available at:
https://weakdh.org/imperfect-forward-secrecy.pdf
David Adrian, Karthikeyan Bhargavan, Zakir Durumeric, Pierrick Gaudry, Matthew Green, J. Alex Halderman, Nadia Heninger, Drew Springall, Emmanuel Thome, Luke Valenta, Benjamin VanderSloot, Eric Wustrow, Santiago Zanella-Beguelin, and Paul Zimmermann reported this vulnerability.
|
Impact:
A remote user that can conduct a man-in-the-middle attack can cause the target system to use weak cryptography that can be decrypted.
|
Solution:
The vendor has issued a fix.
The vendor's advisory is available at:
http://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2015-008.txt.asc
|
Vendor URL: ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2015-008.txt.asc (Links to External Site)
|
Cause:
Authentication error
|
|
Message History:
None.
|
Source Message Contents
|
|
|
[Original Message Not Available for Viewing]
|
|
