[tpm2] Re: Is the tpm2_create command safe against sniffing attacks?
Dimitar Tomov <dimi at designfirst.ee>
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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)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?
1. tpm2_createprimary -Q -C o -c prim.ctx
2. 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
3. tpm2_load -Q -C prim.ctx -u seal.pub -r seal.priv -n seal.name -c seal.ctx
4. 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.
[https://mail.zeronsoftn.com/mthumbnail/ffbd1000-b8b6-44ea-b660-35333967ae6e.png]
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<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 </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="LPlnk619952">https://github.com/wolfSSL/wolfTPM/blob/b0a65e44b8a25be88b2f9ff4e35fbf08360e5d01/examples/nvram/store.c#L121</a> </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 <a href="https://developers.tpm.dev/posts/15883726" id="LPlnk">https://developers.tpm.dev/posts/15883726</a> </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);">
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Joseph Lee (ZeronsoftN) <[email protected]><br>
<b>Sent:</b> Saturday, July 31, 2021 2:09 AM<br>
<b>To:</b> [email protected] <[email protected]><br>
<b>Subject:</b> [tpm2] Is the tpm2_create command safe against sniffing attacks?</font>
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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> 1. Is there a tool in linux that can sniff communication with the current system's TPM?</div>
<div> 2. How to encrypt communications if the methods described above are not secure?<br>
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>
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