robertthompson
Contributor
Contributor

SEG .awsec Files and Keys

I did a training for a contractor for the USA Dept of Energy this week and these detailed questions came up that I couldn't quite answer on the spot.  I opened ticket # 775555 that is summarized below and may be helpful to you as well.  Enjoy if so.

Do we have any documentation around the process flow for how .awsec files are

created by the SEG?  Further, where any related encryption key is generated,

stored and passed on to the device? 

Then any guidance/details around how this could be compromised and any safeguards around how any cert could be used maliciously to open an .awsec file outside of normal use cases.

The process flow is described below:

Device enrolls with AirWatch

Create an encryption key unique to user/device combination

Encryption key is stored in the cache of the SEG

Device syncs for email or downloads attachments

SEG proxies request through to EAS server if request is allowed

EAS server responds with content

SEG encrypts attachment, applies new file header and appends new .awsec file type

AWSEC file type unique to SCL and can only be read by SCL

Header is uniquely generated for each attachment, so each attachment is encrypted uniquely

Encrypted attachment is received by the device and SCL checks its keystore for an encryption key whose hash matches the hash in the file header

If verification passes, the file is decrypted and can be viewed in the SCL

If verification fails, the SCL calls an endpoint to retrieve the encryption key and once SCL receives it, SCL decrypts the file

The device creates an encryption key when it’s enrolled.

The Encryption key is stored in the SEG cache.

The attachments sent to the SEG have the mime type changed to awsec along with the file name appending the .awsec.

When you say the header is uniquely generated, is this the mime type?

How does the AWDS send files to the devices? Are these sent encrypted at the transport layer and not at the file layer?

Yes and yes. The header has the mime type in it and the files are sent at the transport layer.

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adamesch
Contributor
Contributor

Another fun fact about SEGs:  They require Intel processors to do what Robert described below, as AMD processors are not as well-optimized for AES encryption. Most new processors have instructions built in to their instruction sets that allow for encryption / decryption to happen on the hardware level, and someone in support was unlucky enough to find that key processing between API and AMD-based SEG servers was taking multiple minutes to complete at 100% CPU utilization. Having the customer switch to Intel-based processors resolved timeout errors and high CPU utilization.

Blaming the hardware isn’t always crazy!

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