Linked Questions

4 votes
1 answer
5k views

LogJam hardening OpenSSH and testing it [duplicate]

I would like to harden my OpenSSH (clientsite) after the LogJam attack. I read this article https://weakdh.org/sysadmin.html and there is one paragraph, which says how to do that. Is this enough and ...
Loretta's user avatar
  • 43
0 votes
1 answer
915 views

How can a RSA-2048 certificate be vulnerable to logjam attack? [duplicate]

Most likely I am missing some fundamentals: Our web servers are secured with TLS encryption. We use RSA-2048 bit certificates. The logjam attack targets the DH algorithm. How can our web servers be ...
gunnar247's user avatar
33 votes
2 answers
15k views

What is the current security status of Diffie-Hellman key exchange?

There is a web site weakdh.org, whose name alone would certainly cause some feeling of uncertainty in using DH among people who are not experts IMHO. Could some knowledgeable person kindly say ...
Mok-Kong Shen's user avatar
9 votes
3 answers
5k views

Does the recommended course of action for preventing Logjam on Tomcat servers really eliminate all risks of weak DH keys?

Can anyone verify this fix secures against the Logjam vulnerability for Apache Tomcat? I'm sceptical about it's effectiveness, since it doesn't mention how to implement the user defined 2048 bit DH ...
Casper's user avatar
  • 93
9 votes
1 answer
2k views

Regenerating dhparam periodically

Does it increase connection security if I regenerate the dhparam files used with NGINX on our servers periodically e.g. every week? What issues may arise from this? Is there any benefit in doing ...
Bent's user avatar
  • 225
8 votes
1 answer
1k views

Do Diffie-Hellman parameters need to be recreated regularly?

Having generated 2048-bit DH params, do I need to regenerate them regularly? If so, how frequently should I do this?
Roger Lipscombe's user avatar
5 votes
1 answer
3k views

How to create most secure SSH keys and D-H moduli on standard Linux PC?

These are two questions so closely related that I am asking them together - hope that's OK. When I create new SSH keys (e.g. with ssh-keygen -t rsa -b 4096 or ... 8192); and when I create new prime ...
Ned64's user avatar
  • 255
3 votes
1 answer
2k views

Cipher suites vulnerable to logjam

The following is a list of ciphers, how to know which ciphers are vulnerable to LogJam attack? Client shared list of ciphers: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA ...
Prem M's user avatar
  • 31
2 votes
2 answers
332 views

Can a user verify the quality/safety of pregenerated SSH moduli parameters?

Many tutorials about how to mitigate the Logjam recommend regenerating Diffie-Hellman moduli. This is a resource intensive operation, especially for high-bit groups. This made me think if it made ...
tarleb's user avatar
  • 1,200
2 votes
1 answer
258 views

How 'Logjam' attack affects openID since it uses Diffie-Hellman key exchange method?

According to the Diffie-Hellman key exchange get affected by logjam, and openID uses this to establish an association. So how this going to affect OpenID?
Thanuja's user avatar
  • 123