[Spce-user] Hide customer password in Kamailio DB

Fri May 1 17:25:55 EDT 2015

The authentication reponse is calculated as follows:

HA1=MD5<http://en.wikipedia.org/wiki/MD5>(username:realm<http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Authentication_Realms>:password)
HA2=MD5<http://en.wikipedia.org/wiki/MD5>(method:digestURI)
response=MD5<http://en.wikipedia.org/wiki/MD5>(HA1:nonce:HA2)

Assume HA1 is known. HA2 is based on the initial request, let's assume method=INVITE and digestURI=sip:123456789 at sipwise.com<mailto:123456789 at sipwise.com>, so you can just invike MD5 with those 2 values and you will have HA2.
For the response you will need the nonce provided by NGCP in SIP 407 Proxy Authentication Required.
All you need to do is invoke MD5 with HA1, the nonce received from NGCP and HA2.

So where do I need the plain password? Remember that HA1  is known by the attacker in this scenario.

As an additional information, some software like Asterisk allows you to provide HA1 instead of clear text password for inbound and outbound authentication, so you don't even have to write a specific exploit kit.

Regards,

Marc

On 1 mai 2015, at 08:28, Daniel Grotti <dgrotti at sipwise.com<mailto:dgrotti at sipwise.com>> wrote:

Hi Marc,
Basically the ha1 is stored in the db and you can tell kamailio to use the ha1 password to compare against to the authentication values provided in the sip header.
You still need need though to insert the plain text password in your client if you want to authenticate and not the ha1 stored in the db. So since the ha1 is irreversible (based to md5) you cannot practically spoof the password like you can in plain text. This is what Raul is trying to say.

Raul, reason why we store plain text is basically because we won't be able to provisioning phones with ha1.

Daniel
On May 1, 2015 7:55 AM, Raúl Alexis Betancor Santana <rabs at dimension-virtual.com<mailto:rabs at dimension-virtual.com>> wrote:

HOW do you generate a correct authentication with the HASH values? ... it's mathematicatly imposible, it's a HASH result, count not be reversed.

If you have the HA_1 and HA1_2 values AND you know the realm and the user URI, the most dangerous thing you could do ... it's try a brute-force attack, having the HASH values, you could do it localy, whitout sending AUTH attemps agains the SPCE, so not been banned, but that's all

The HASH values could not be reversed, on the other hand ... if someone have access to your DB, your minor problem it's them to get the hash values.

________________________________

De: "Marc Storck" <mstorck at voipgate.com<mailto:mstorck at voipgate.com>>
Para: spce-user at lists.sipwise.com<mailto:spce-user at lists.sipwise.com>
Enviados: Jueves, 30 de Abril 2015 22:30:32
Asunto: Re: [Spce-user] Hide customer password in Kamailio DB

Unfortunately that's not completely correct.

You can not only check but also generate a correct authentication with the unencrypted HASH values.

So the storing HA1 and HA1_2 in the DB is no better than storing the password in DB. The only difference is that HA1 and HA1_2 don't reveal the underlying password.

If someone has access to your DB that someone can use the HA1 and HA1_2 values to authenticate correctly against you system and make fraudulent calls.

Which is why I also call the HASH values "unencrypted".

Regards,

Marc
________________________________
From: Spce-user [spce-user-bounces at lists.sipwise.com<mailto:spce-user-bounces at lists.sipwise.com>] on behalf of Raúl Alexis Betancor Santana [rabs at dimension-virtual.com<mailto:rabs at dimension-virtual.com>]
Sent: Thursday, April 30, 2015 18:11
To: <spce-user at lists.sipwise.com<mailto:spce-user at lists.sipwise.com>>
Subject: Re: [Spce-user] Hide customer password in Kamailio DB

Marc,

HA1 and HA1_2 are not 'unencrypted' text ... they are HASH values, generated from the user URI, the REALM and the PASSWORD ... your could not use the HA1 and HA1_2 values for anything than 'check' if the sended (by the SIP UA) credentials are Ok, you could not use them to 'know' the unencrypted password.

Best regards

________________________________

De: "Marc Storck" <mstorck at voipgate.com<mailto:mstorck at voipgate.com>>
Para: "<spce-user at lists.sipwise.com<mailto:spce-user at lists.sipwise.com>>" <spce-user at lists.sipwise.com<mailto:spce-user at lists.sipwise.com>>
Enviados: Jueves, 30 de Abril 2015 12:57:35
Asunto: Re: [Spce-user] Hide customer password in Kamailio DB

What is the difference from reading the plain text (unencrypted) password or reading the plain text (unencrypted) HA1 and HA1_2 values from DB?

AFAIK, an attacker, who was able to read either of them from your DB, can use those values to correctly authenticate to the SPCE in any case.

On 30 Apr 2015, at 13:45, Mathys Frédéric <frederic.mathys at nagra.com<mailto:frederic.mathys at nagra.com>> wrote:
Hello,

When creating a new user, by default the password is saved in plaintext in the DB, column “password”. For obvious security reasons, I’d like to remove the password in this column and use only ha1 and ha1b values. To do that, I modified the “auth_db” module configuration :

/etc/kamailio/proxy/kamailio.cfg
modparam("auth_db", "use_domain", 1)
modparam("auth_db", "calculate_ha1", 0)
modparam("auth_db", "password_column", "ha1")
modparam("auth_db", "password_column_2", "ha1_2")

Then, I removed the password for all users in the DB, and everyone seems able to connect with this configuration. My problem is now when I create a new user, the password is automatically saved in plaintext and I don’t want that. So I tried to modify “kamctlrc” by adding the following line :

/etc/kamailio/proxy/kamctlrc and /etc/kamailio/lb/kamctlrc
STORE_PLAINTEXT_PW=0

This has no effect, what should I do to disable that?

Thank you

Frederic Mathys
System Integration & Validation Engineer
P Please consider the environment - do you really need to print this email ?

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