evilghost
Premium
join:2003-11-22
Springville, AL
 ·Windstream
3 edits | reply to BeesTea
Re: Heads Up: Debian OpenSSL RNG Vuln CVE-2008-0166
I'm reminded why I don't like Ubuntu when the openssh-server and openssh-client packages are held back requiring the installation of openssh-blacklist as a requirement.
Dear Ubuntu Team, I'm not going to use ssh-vulnkey to see if my system is vulnerable, I'm reissuing keys. Why is this package a requirement for the openssh-server package? Cut me a freaking break. |
|
evilghost
Premium
join:2003-11-22
Springville, AL | reply to BeesTea
Good info here:
»wiki.debian.org/SSLkeys |
|
BeesTea
Network Janitor
Premium,VIP
join:2003-03-08
00000 | That wiki entry is excellent. I'd recommend everyone read it, specifically the list of likely affected software.
Thanks for sharing! |
|
BeesTea
Network Janitor
Premium,VIP
join:2003-03-08
00000
| reply to BeesTea
H D Moore, of the Metasploit project etc, has made the following write up.
http://metasploit.com/users/hdm/tools/debian-openssl/
Of note is the FAQ
quote:
Frequently Asked Questions
Q: How long did it take to generate these keys?
A: About two hours for the 1024-bit DSA and 2048-bit RSA keys for x86. I used 31 Xeon cores clocked at 2.33Ghz. I am generating the RSA 4096-bit keys now and the total time should be about 18 hours.
Q: Will you share your code for distributing the key-generation across mulitple processors?
A: Nope. The code is hardcoded for this specific cluster and is too poorly-written to be worth cleaning up.
Q: How long does it take a crack a SSH user account using these keys?
A: This depends on the speed of the network and the configuration of the SSH server. It should be possible to try all 32,767 keys of both DSA-1024 and RSA-2048 within a couple hours, but be careful of anti-brute-force scripts on the target server.
Q: I use 16384-bit RSA keys, can these be broken?
A: Yes, its just a matter of time and processing power. For mere mortals, 4096-bit keys are already a little on the paranoid side. All possible 4096-bit keys should be available within the next day or so. It is possible to generate all combinations of 8192-bit and 16384-bit keys, but I probably have better uses for my processors 
Scary.
Folks, if you're not already, pay close attention to excessive connections to your crypto services like ssh, vpn, etc. ~32,000 attempts can go by fast.
--
Overpower, overcome. |
|
deblin
Dark Side of the Moon
Premium,MVM
join:2001-09-01
Middletown, DE
1 edit | Nevermind, standard log messages from the brute force attackers, not necessarily anything significant to this. |
|
BeesTea
Network Janitor
Premium,VIP
join:2003-03-08
00000
1 edit | SSH scanning is increased considerably across the Internet.
http://www.securityfocus.com/news/11518?ref=rss
It's important to consider that simply having ssh-key auth enabled is not enough to be compromised. A user would still need to be using a vulnerable key for authentication. In practical experience, public-key is way less common than simple password auth with ssh. This means the more likely attack vector will be session keys. Considering that password auth for ssh is plain taxt pushed through the session tunnel, I'd be more worried about that. Someone sniffing TCP/22 and cracking it at their leisure would result in essentially plain text logins and passwords.
EDIT: Typo |
|
evilghost
Premium
join:2003-11-22
Springville, AL
·Windstream
| said by BeesTea  :SSH scanning is increased considerably across the Internet. http://www.securityfocus.com/news/11518?ref=rssIt's important to consider that simply having ssh-key auth enabled is not enough to be compromised. A user would still need to be using a vulnerable key for authentication. In practical experience, public-key is way less common than simple password auth with ssh. This means the more likely attack vector will be session keys. Considering that password auth for ssh is plain taxt pushed through the session tunnel, I'd be more worried about that. Someone sniffing TCP/22 and cracking it at their leisure would result in essentially plain text logins and passwords. EDIT: Typo One thing to consider would be password-less keypairs, for example, I use these at home on my trusted computers for sshfs to avoid password prompts. It's my understanding that if someone knew the compromised keypair and username they could successfully authenticate without password. |
|
visitor_
@proxad.net | reply to BeesTea
I hope the following doesn't lower the otherwise highly admirable tone of this thread too excessively:
»xkcd.com/424/
|
|
No_Strings
Premium,Mod
join:2001-11-22
The OC | "Ubuntu - Turns out distro is actually just Windows Vista wth a few custom themes."
Something some of us have suspected for a long time. |
|
evilghost
Premium
join:2003-11-22
Springville, AL | reply to BeesTea
I walked in this morning and had this printout on my cube wall. Awesome. |
|
