Admins eHow SysAdmin Tips & Tricks

September 14, 2011

An analysis of recent security breach to DigiNotar and Man-In-The-Middle attack to Iranian users

Filed under: General,Security — Tags: , , , , , , , — admin @ 9:23 am

As I have received several requests from Iranian readers of my blog, I have done some analysis on recent DigiNotar security breach and MITM attack to Iranian users.
This analysis is based on Fox-IT interim report of breach. You can download the complete report in PDF Format from the following link :
http://www.adminsehow.com/wp-content/uploads/2011/09/rapport-fox-it-operation-black-tulip-v1-0.pdf

What is MITM attack and how to prevent it ?
MITM stands for Man-In-The-Middle. it simply means someone stands between you and destination and intercepts or modifies your communication. it is quite easy when communication is not encrypted.
SSL protocol is originally invented to address this issue. The idea is that a trusted Authority (CA) authenticates the identity of destination and by using some cryptography protocols your connection to authentic destination becomes encrypted and impossible to intercept or modify.
It has been shown that the cryptography methods like AES or RC4 which are employed to encrypt the data are quite effective and very hard to crack. so the easier solution is to attack the base of trust model, the trusted authorities (CA). In this kind of attacks, hackers break into CA systems and forge valid certificates for themselves so they can impersonate themselves as authentic destinations and intercept the data. this kind of attack is used in both recent incidents, Commodo and DigiNotar.
Although the protocol is almost safe itself, unfortunately many of these CAs are vulnerable themselves making the whole process vulnerable.
The FOX-IT report indicates the DigiNotar systems were using Windows (Which is vulnerable in nature) and passwords has been crackable through brute-force attack. (More on this later)

To understand it better, I have created a diagram of recent MITM attack to Iranian users with the goal of intercepting communications between them and Google. the attackers have been able to gain access to Google accounts of users through this attack :

This diagram is self-explanatory. The attacker in middle impersonates itself as Google and establishes a secure connection to the user which is signed by DigiNotar CA. Although the connection is still secure, but users have a secure connection to the attacker, not real Google. so attacker has access to all information sent by user, including username, passwords, cookies and etc.
(more…)

March 29, 2011

A response to ComodoHacker

Filed under: General,Security — Tags: , , — admin @ 5:03 am

I was following up the news regarding the recent attacks to Comodo and gaining access to their cert signing system. Today I found out he has posted some comments regarding his attack and claimed some nonsense , so I decided to write a response to him , here it goes :

First of all you have claimed you are only a 21 years kid , are you kidding ? the aim of the attack has been to create certs signed by Comodo CAs for mail.google.com and login.yahoo.com and etc which can only be used to do man-in-middle type of attack. in fact if you do not have access to internet infrastructure in Iran , these certs have no use ! why would a 21 years old kid want to do that ? if you are interested in some signed certs which can not be used anywhere , next time send an email to me , I will sign some certs myself and send it back to you 🙂 it is very clear that this attack has been done with cooperation of Iran’s government and Iranian revolutionary guards and their cyber army who have access to Iran’s IT infrastructure.

Second I agree what you have done is impressive. it shows your budget and the size of your criminal organization to find security holes in internet. but you have not compromised anything fundamental or serious on internet ! do you think the same trick which you use on Iranian people ( I mean bragging about your power ) will work on the world either ? in fact when I was 21 I could do better than you ( your whole criminal organization ). lol , I can send you some proofs if you like.
because you have signed fake certs for yahoo and google, many people think you have hacked their systems and compromised their security ! but pro people know it has nothing to do with google or yahoo or the security of their systems. everything is intact and secure.
The only companies who should be blamed are Comodo and their Italian partner because of  weak security system and I am sure they are already in a lot of trouble by authorities 🙂

Third you talk about breaking RSA 2048 keys and so on , it just makes me laugh. you can not even break the security of RSA 16 bit ! lol
If you had the power to do that , there were no need to generate fake certs from Comodo , you generated these fake certs because you can not decrypt the SSL traffic in Iran ! you need fake signed certs to do man-in-middle attack. it itself shows how weak you are. so come on , do not brag about your power. we all know thats a big lie.

Fourth lets assume you gain access to Comodo root CAs so you can sign the certs yourself , I dont think there is any bigger achievement for you ! you know what happens ? in less than 24 hours all major browsers will update their software and revoke the certificate. as simple as that. so I recommend you to waste your time on better solutions.

Fifth I would like to thank you guys for doing this personally , what you did had no gains for you and showed your real face to the world. I am not going to get political on this post 🙂 but it had a lot of benefits to the security of the internet. I am sure authorities are already working on implementing more secure and safe procedures to generate certificates and check for revoked certs. Thank You.

And at last I would like to talk to Iranian people , they are just trying to frighten you. they have not compromised anything serious on internet. this attack shows they have nothing in hand. these fake certs CAN NOT be used the decrypt SSL traffic. always use VPN encrypted connections and for emails use SSL connections , Gmail is the best. also always use the latest versions of Google Chrome and Firefox for browsing the web. NEVER USE INTERNET EXPLORER ! not even version 9. and you will be safe 🙂

Here is the link to hacker speech : http://pastebin.com/74KXCaEZ

May 11, 2010

“ASN1 bad tag value met” error when processing a certificate request in IIS 7

Filed under: IIS,Windows — Tags: , , , , , — admin @ 12:48 pm

We’ve seen a few instances of the following error message on 64 bit servers when IIS 7.0 is attempting to process a pending certificate request:

Complete Certificate Request
There was an error while performing this operation.
Details:
CertEnroll::CX509Enrollment::p_InstallResponse: ASN1 bad tag value met. 0x8009310b (ASN: 267)

This error seems to mean that the private key (created when the certificate request was made) does not match the public key (the .crt file). The keypair is not successfully joined into a working SSL certificate.
So far this behavior seems most common with .crt files (instead of the .cer files many of us are more used to) issued by one specific Certification Authority—which will remain nameless here.
The error shows up after reaching the point in the process where you ‘specify certificate authority response’ and guide the wizard to the ‘File name containing the certification authority’s response…’ (the .crt file).

Solution :
Begin by importing the .crt file into the Personal certificate store for the local computer. (Start button > Run: MMC > File Menu > Add/Remove Snap-in > highlight Certificates snap-in and click the ADD button > select Computer Account and click Finish > Click OK > drill into Personal > Certificates > right-click and select All Tasks > select Import > guide to the .crt file.) At this point your certificate is basically a half-certificate. It is still missing its private key.
Second, double-click the crt certificate file you just imported, select the Details tab, scroll all the way down to Thumbprint and highlight Thumbprint. In the lower pane, block and copy all the letters of the thumbprint. Paste the thumbprint characters into notepad. Open the command prompt and run this command: Certutil /?
The command you’ll want to run is:

certutil -repairstore my "{insert all of the thumbprint characters here}"

When you see the response: “CertUtil: -repairstore command completed successfully” you should have a private key associated with the .crt file in the personal store. There should no longer be any need to run through the “Complete Certificate Request…” wizard. The certificate should show up in the IIS Manager’s list of server certificates at this point. It should also be available in the SSL Certificates drop-down list when attempting to edit the https binding for a website.

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