Debian OpenSSL Predictable PRNG Bruteforce SSH Exp

From subaozi s blog

I have seen this vulnerability a long time ago, but I didn't pay too much attention to it because Y was from bruteforce. I talked to a friend yesterday about this vulnerability. I checked it carefully and found it very dangerous, however, certain conditions are required.

EXP in http://www.milw0rm.com/exploits/5622

I will explain the causes and consequences of this vulnerability with a superficial and amateur level. I would like to give you some advice on what is wrong and what needs to be refined.

Cause: When a random number is obtained, due to a libssl function problem, the random number is random in the pid range. The pid should be 1-(I don't know why we have come up with more than values, it doesn't matter. It's better to lose it anyway ). As a result, authentication using the libssl Library such as ssh openvpn can be collided within a certain range.

Consequence: You can use the collided ssk key and use the relevant account to remotely log on to ssh.

Prerequisites:

1. The other party's system has this vulnerability.

2. An account in the other system uses pub key for authentication.

3. You know that the root account is the first choice. If I remember correctly, PermitRootLogin In debian is Yes by default. If Y uses pubkey, bingo is used.

If you are interested in viewing more detailed details, visit the http://digitaloffense.net/tools/debian-openssl/.

The final repair method is simple: apt-get update; apt-get upgrade. Debian never restarts. Some people saw a debian machine and ran it for about 1400 days. The patch of the application was very good, but the kernel patch was not complete.