[tpm2] Re: Is the tpm2_create command safe against sniffing attacks?

Joseph Lee (ZeronsoftN) <joseph at zeronsoftn.com> Mon, 02 Aug 2021 03:33:27 +0000

Newsgroups	dev.linux.lists.tpm2
Message-ID	<em88323757-8498-4647-824b-92f556741c1a@desktop-hihridj>

Hi Dimi,

Sorry to bother you. By installing the latest version of tpm2-tools, 
encrypted communication is possible.
Seal/unseal was possible as shown below.

But I have one question. How can I detect if a MITM attack occurs during 
the seal/unseal process? After establishing a session, is there any way 
to get the EK certificate of that session?
It seems that the tpm2_getekcertificate command can only get 
certificates created via the createek command. I'd like to know if the 
TPM I've made a session with is genuine.

Seal:
 > tpm2_createprimary -c prim.ctx
 > tpm2_startauthsession --hmac-session -c prim.ctx -S sess.ctx
 > tpm2_create -Q -g sha256 -u seal.pub -r seal.priv -i temp.key -C 
prim.ctx -S sess.ctx
 > tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n seal.name -c 
seal.ctx
 > tpm2_evictcontrol -C o -c seal.ctx 0x81010001
 > tpm2_flushcontext sess.ctx

Unseal:
 > tpm2_startauthsession --hmac-session -c prim.ctx -S sess.ctx
 > tpm2_unseal -c seal.ctx -S sess.ctx -o out.key
 > tpm2_flushcontext sess.ctx

Thanks & Regards,
Joseph

------ Original Message ------
보낸 사람: "Joseph Lee (ZeronsoftN)" <joseph(a)zeronsoftn.com>
받는 사람: "Dimitar Tomov" <dimi(a)designfirst.ee>; "tpm2(a)lists.01.org" 
<tpm2(a)lists.01.org>
보낸 날짜: 2021-08-02 오전 6:27:36
제목: [tpm2] Re: Is the tpm2_create command safe against sniffing attacks?

>Hi Dimi,
>
>Thank you for your kind answer. Looking at the link you gave, I think I 
>can get more ideas.
>
>I've been trying session encryption via tpm2-tools all weekend.
>But I haven't found a way to create an encrypted session in tpm2-tools 
>yet. Maybe tpm2-tools doesn't support encrypted sessions?
>
>If this is clear, I will implement parameter encryption through 
>tpm2-tools with referring to wolfTPM.
>
>Thanks & Regards,
>Joseph
>
>------ Original Message ------
>보낸 사람: "Dimitar Tomov" <dimi(a)designfirst.ee>
>받는 사람: "tpm2(a)lists.01.org" <tpm2(a)lists.01.org>; "Joseph Lee 
>(ZeronsoftN)" <joseph(a)zeronsoftn.com>
>보낸 날짜: 2021-08-02 오전 4:33:02
>제목: [tpm2] Re: Is the tpm2_create command safe against sniffing 
>attacks?
>
>>Hi Joseph,
>>
>>TPM 2.0 offers Parameter Encryption capability and HMAC sessions as 
>>measures against Man-in-the-middle attacks
>>
>>Examples in wolfTPM demonstrate how to enable Parameter Encryption
>>
>>  
>>https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121
>>
>>There is also Keygen , Key import and Key loading examples with 
>>Parameter Encryption
>>
>>https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121
>>
>>Last week we discussed the Dolos Group story about a stolen laptop 
>>with TPM https://developers.tpm.dev/posts/15883726
>>
>>If Parameter Encryption and HMAC session have been used, this story 
>>would have developed differently.
>>
>>Hope this helps.
>>
>>Dimi
>>--
>>Founder of TPM.dev
>>
>>--------------------------------------------------------------------------------
>>From: Joseph Lee (ZeronsoftN) <joseph(a)zeronsoftncom 
>><mailto:joseph(a)zeronsoftn.com>>
>>Sent: Saturday, July 31, 2021 2:09 AM
>>To:tpm2(a)lists.01.org <tpm2(a)lists.01.org>
>>Subject: [tpm2] Is the tpm2_create command safe against sniffing 
>>attacks?
>>
>>Hello,
>>
>>https://pulsesecurity.co.nz/articles/TPM-sniffing
>>In this article, can see that communication with the TPM is vulnerable 
>>to sniffing if not careful.
>>
>>https://tpm2-software.github.io/2020/04/13/Disk-Encryption.html
>>Is the disk encryption described in tpm2-software's blog safe against 
>>these attacks?
>>
>>tpm2_createprimary -Q -C o -c prim.ctx
>>dd if=/dev/urandom bs=1 count=32 status=none | tpm2_create -Q -g 
>>sha256 -u seal.pub -r seal.priv -i- -C prim.ctx
>>tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n seal.name -c 
>>seal.ctx
>>tpm2_evictcontrol -C o -c seal.ctx 0x81010001
>>
>>My question is:
>>     1. Is there a tool in linux that can sniff communication with the 
>>current system's TPM?
>>     2. How to encrypt communications if the methods described above 
>>are not secure?
>>         It seems that encryption is possible through 
>>tpm2_startauthsession , but I do not know how to apply it to 
>>tpm2_create . (The -S option simply did not work.)
>>
>>Thank you.
>>
>>
>>
>>
>
>
>

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<body><div>Hi Dimi,</div><div><br></div><div>Sorry to bother you. By installing the latest version of tpm2-tools, encrypted communication is possible.</div><div>Seal/unseal was possible as shown below.</div><div><br></div><div>But I have one question. How can I detect if a MITM attack occurs during the seal/unseal process? After establishing a session, is there any way to get the EK certificate of that session?
</div><div>It seems that the tpm2_getekcertificate command can only get certificates created via the createek command. I'd like to know if the TPM I've made a session with is genuine.</div><div><br></div><div>Seal:</div><div>&gt; tpm2_createprimary -c prim.ctx
</div><div><span>&gt;&nbsp;</span>tpm2_startauthsession --hmac-session -c prim.ctx -S sess.ctx
</div><div><span>&gt;&nbsp;</span>tpm2_create -Q -g sha256 -u seal.pub -r seal.priv -i temp.key -C prim.ctx -S sess.ctx
</div><div><span>&gt;&nbsp;</span>tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n seal.name -c sealctx
</div><div><span>&gt;&nbsp;</span>tpm2_evictcontrol -C o -c seal.ctx 0x81010001
</div><div><span>&gt;&nbsp;</span>tpm2_flushcontext sess.ctx
</div><div><br></div><div>Unseal:</div><div><span>&gt;&nbsp;</span>tpm2_startauthsession --hmac-session -c prim.ctx -S sess.ctx
</div><div><span>&gt;&nbsp;</span>tpm2_unseal -c seal.ctx -S sess.ctx -o out.key
</div><div><span>&gt;&nbsp;</span>tpm2_flushcontext sess.ctx</div><div><br></div><div>Thanks &amp; Regards,
</div><div>Joseph</div>
<div><br></div>
<div>------ Original Message ------</div>
<div>보낸 사람: "Joseph Lee (ZeronsoftN)" &lt;<a href="mailto:[email protected]">[email protected]</a>&gt;</div>
<div>받는 사람: "Dimitar Tomov" &lt;<a href="mailto:[email protected]">[email protected]</a>&gt;; "<a href="mailto:[email protected]">[email protected]</a>" &lt;<a href="mailto:[email protected]">[email protected]</a>&gt;</div>
<div>보낸 날짜: 2021-08-02 오전 6:27:36</div>
<div>제목: [tpm2] Re: Is the tpm2_create command safe against sniffing attacks?</div><div><br></div>
<div id="x540a56993bca4ed"><blockquote cite="embc50f58e-9f9d-4b11-8f71-8ebc3d052ec0@desktop-hihridj" type="cite" class="cite2">
<div>Hi Dimi,</div><div><br></div><div>Thank you for your kind answer. Looking at the link you gave, I think I can get more ideas.
</div><div><br></div><div>I've been trying session encryption via tpm2-tools all weekend.
</div><div>But I haven't found a way to create an encrypted session in tpm2-tools yet. Maybe tpm2-tools doesn't support encrypted sessions?</div><div><br></div><div>If this is clear, I will implement parameter encryption through tpm2-tools with referring to wolfTPM</div><div><br></div><div><span>Thanks &amp; Regards,</span></div><div>Joseph</div>
<div><br></div>
<div>------ Original Message ------</div>
<div>보낸 사람: "Dimitar Tomov" &lt;<a href="mailto:[email protected]" style="">[email protected]</a>&gt;</div>
<div>받는 사람: "<a href="mailto:[email protected]" style="">[email protected]</a>" &lt;<a href="mailto:[email protected]" style="">[email protected]</a>&gt;; "Joseph Lee (ZeronsoftN)" &lt;<a href="mailto:[email protected]">[email protected]</a>&gt;</div>
<div>보낸 날짜: 2021-08-02 오전 4:33:02</div>
<div>제목: [tpm2] Re: Is the tpm2_create command safe against sniffing attacks?</div><div><br></div>
<div id="x8ebb9e3798dc4fa"><blockquote cite="HE1PR08MB265161B58D8BE61444DD11B5B5EE9@he1pr08mb2651.eurprd08prod.outlook.com" type="cite" class="cite2">

<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
Hi Joseph,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
TPM 2.0 offers Parameter Encryption capability and HMAC sessions as measures against Man-in-the-middle attacks</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
Examples in wolfTPM demonstrate how to enable Parameter Encryption&nbsp;</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
&nbsp;<a href="https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121" id="LPlnk619952">https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121</a>&nbsp;</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
There is also Keygen , Key import and Key loading examples with Parameter Encryption</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<a href="https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121" id="LPlnk585337">https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121</a><br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
Last week we discussed the Dolos Group story about a stolen laptop with TPM&nbsp;<a href="https://developers.tpm.dev/posts/15883726" id="LPlnk">https://developers.tpm.dev/posts/15883726</a>&nbsp;</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
If Parameter Encryption and HMAC session have been used, this story would have developed differently.</div>
<br>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
Hope this helps.</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
Dimi</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
--</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
Founder of TPM.dev</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">
<br>
</div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Joseph Lee (ZeronsoftN) &lt;<a href="mailto:[email protected]">joseph@zeronsoftncom</a>&gt;<br>
<b>Sent:</b> Saturday, July 31, 2021 2:09 AM<br>
<b>To:</b> <a href="mailto:[email protected]">[email protected]</a> &lt;<a href="mailto:[email protected]">[email protected]</a>&gt;<br>
<b>Subject:</b> [tpm2] Is the tpm2_create command safe against sniffing attacks?</font>
<div>&nbsp;</div>
</div>
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<div>Hello,
<div><br>
</div>
<div><a href="https://pulsesecurity.co.nz/articles/TPM-sniffing">https://pulsesecurity.co.nz/articles/TPM-sniffing</a></div>
<div>In this article, can see that communication with the TPM is vulnerable to sniffing if not careful.<br>
<div><br>
</div>
<div><span style="color:#00E; background-color:rgba(0,0,0,0); text-decoration:underline solid #00E"><a href="https://tpm2-software.github.io/2020/04/13/Disk-Encryption.html">https://tpm2-software.github.io/2020/04/13/Disk-Encryption.html</a></span></div>
<div>Is the disk encryption described in tpm2-software's blog safe against these attacks?</div>
<div><br>
</div>
<ol style="margin:0px 0px 15px 30px; padding:0px; color:rgb(17,17,17); background-color:rgb(253,253,253)">
<li style=""><code class="x_language-plaintext x_highlighter-rouge" style="font-size:15px; border:1px solid #E8E8E8; border-radius:3px; background-color:#EEF; padding:1px 5px">tpm2_createprimary -Q -C o -c prim.ctx</code><br style="">
</li><li style=""><code class="x_language-plaintext x_highlighter-rouge" style="font-size:15px; border:1px solid #E8E8E8; border-radius:3px; background-color:#EEF; padding:1px 5px">dd if=/dev/urandom bs=1 count=32 status=none | tpm2_create -Q -g sha256 -u seal.pub
 -r seal.priv -i- -C prim.ctx</code><br style="">
</li><li style=""><code class="x_language-plaintext x_highlighter-rouge" style="font-size:15px; border:1px solid #E8E8E8; border-radius:3px; background-color:#EEF; padding:1px 5px">tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n seal.name -c seal.ctx</code><br style="">
</li><li style=""><code class="x_language-plaintext x_highlighter-rouge" style="font-size:15px; border:1px solid #E8E8E8; border-radius:3px; background-color:#EEF; padding:1px 5px">tpm2_evictcontrol -C o -c seal.ctx 0x81010001</code></li></ol>
<div><br>
</div>
<div>My question is:</div>
<div>&nbsp; &nbsp; 1. Is there a tool in linux that can sniff communication with the current system's TPM?</div>
<div>&nbsp; &nbsp; 2. How to encrypt communications if the methods described above are not secure?<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;It seems that encryption is possible through tpm2_startauthsession , but I do not know how to apply it to tpm2_create . (The -S option simply did not work.)</div>
<div><br>
</div>
<div>Thank you.</div>
<div><br>
</div>
</div>
<div><br>
<br>
<br>
<img style="max-height:32px" src="https://mail.zeronsoftn.com/mthumbnail/ffbd1000-b8b6-44ea-b660-35333967ae6e.png"></div>
</div>
</blockquote></div>


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