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<div class="moz-cite-prefix">On 7/5/2017 02:47, Tobias Brunner
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:d3452cb4-76f7-5721-70c7-6fdbdf9c76ff@strongswan.org">
<pre wrap="">Hi Karl,
</pre>
<blockquote type="cite">
<pre wrap="">Except that I can't install the server's certificate into Android's
storage (whether from the base "Security" tab or in the StrongSwan
client); it refuses and says there's no certificate it can import.
</pre>
</blockquote>
<pre wrap="">
If you tried the import option in the CA certificate view of the app and
it doesn't show up, the mime-type is probably not set correctly (if it
is set correctly the strongSwan app should actually show up when trying
to open that file e.g. in the Downloads app). If it does show up in the
file browser but the import fails, the file might be corrupt.
</pre>
<blockquote type="cite">
<pre wrap="">There's no "trusted" certificate option that I can find either in the
VPN setup on the StrongSwan Android client -- just the selection for
which CA cert to use (either automatic selection or you can pick from
the installed and trusted certificates.)
</pre>
</blockquote>
<pre wrap="">
That's the one. After you imported the server cert into the app you can
select it as a "CA certificate" (you basically set the certificate to
use as trust anchor during authentication).
</pre>
<blockquote type="cite">
<pre wrap="">Going to ECDSA
from an RSA certificate cut the fragments to 2 from 3, but I can't get
it to "1", which would remove the fragmentation problem with connection
setup.
</pre>
</blockquote>
<pre wrap="">
Are you talking about IKE or IP fragments? How big is the IKE_AUTH
response?
</pre>
<blockquote type="cite">
<pre wrap="">Then of course there's the base Windows VPN
security issues to start with (e.g. the proposals it supports and such
-- or more to the point, the ones it doesn't) which, frankly leave me in
awe that our government appears at first blush to use it for
rather-secure things (or do they?)
</pre>
</blockquote>
<pre wrap="">
There is a registry key you can enable so it proposes a slightly better
DH group [1].
Regards,
Tobias
[1]
<a class="moz-txt-link-freetext" href="https://wiki.strongswan.org/projects/strongswan/wiki/Windows7#AES-256-CBC-and-MODP2048">https://wiki.strongswan.org/projects/strongswan/wiki/Windows7#AES-256-CBC-and-MODP2048</a>
</pre>
</blockquote>
<br>
<div class="moz-signature">Yes, there are also some folks trying to
harden the ESP side, but when I used what they claimed worked....
it didn't at all (no agreement on proposal)<br>
<br>
Jul 5 15:50:26 IpGw charon: 05[CFG] received proposals:
ESP:AES_GCM_16_128/NO_EXT_SEQ<br>
Jul 5 15:50:26 IpGw charon: 05[CFG] configured proposals:
ESP:AES_CBC_128/HMAC_SHA2_256_128/NO_EXT_SEQ,
ESP:AES_CBC_128/AES_CBC_192/AES_CBC_256/3DES_CBC/BLOWFISH_CBC_256/HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/HMAC_SHA1_96/AES_XCBC_96/HMAC_MD5_96/NO_EXT_SEQ<br>
Jul 5 15:50:26 IpGw charon: 05[IKE] no acceptable proposal found<br>
Jul 5 15:50:26 IpGw charon: 05[IKE] failed to establish CHILD_SA,
keeping IKE_SA<br>
<br>
What they recommended was... (from Powershell)<br>
<br>
<span style="color: rgb(36, 41, 46); font-family: SFMono-Regular,
Consolas, "Liberation Mono", Menlo, Courier,
monospace; font-size: 11.9px; font-style: normal;
font-variant-ligatures: normal; font-variant-caps: normal;
font-weight: normal; letter-spacing: normal; orphans: 2;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; widows: 2; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: rgba(27, 31,
35, 0.05); text-decoration-style: initial;
text-decoration-color: initial; display: inline !important;
float: none;">Set-VpnConnectionIPsecConfiguration
-ConnectionName "<NAME>" -AuthenticationTransformConstants
GCMAES128 -CipherTransformConstants GCMAES128 -EncryptionMethod
AES128 -IntegrityCheckMethod SHA384 -DHGroup ECP256 -PfsGroup
ECP256</span><br>
<br>
Ref: <a class="moz-txt-link-freetext" href="https://github.com/trailofbits/algo/pull/464">https://github.com/trailofbits/algo/pull/464</a><br>
<br>
-- <br>
Karl Denninger<br>
<a href="mailto:karl@denninger.net">karl@denninger.net</a><br>
<i>The Market Ticker</i><br>
<font size="-2"><i>[S/MIME encrypted email preferred]</i></font>
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