[GNC-dev] New OFX Requirements For USAA FSB

Scott McRae smcrae at parax.com
Sun Feb 7 22:28:45 EST 2021

I'm you want something a bit more automated, I came across mitm-proxy in


This should take care of generating certificates automatically and actually
do the forwarding, etc. You'll need to generate a CA cert for it and
install that in your trusted certificates. Their docs should explain how. I
didn't actually use it, since my manual method ended up working, but this
sounds better suited for your use case.

On Sun, Feb 7, 2021 at 7:23 PM Jean L <ripngo at gmail.com> wrote:

> Wow, that's really cool. I would love to replicate that to be able to
> connect to my bank as I'm sure many would. I wonder if there would be a way
> to make that a bit easier than completely manually.
> At the moment, I have a python script that logs into my bank, make the
> right clicks and downloads the OFX files. Definitely NOT robust so I would
> love to be able to go back to downloading ofx files directly.
> Could you possibly write a small blurb on how to do this, from start to
> finish? That would be super useful for me. On the other hand, I'm not sure
> whether this is 100% within the law, not sure whether the DMCA has
> something to say about this or not :(
> Jean
> On 2/7/2021 7:06 PM, Scott McRae wrote:
> >>* So I decided to give the devil his due and temporarily got a Quicken
> *>>* subscription and setup an SSL man-in-the-middle.
> *>Sure, you can have a man-in-the-middle setup, but if you don't have the
> >keys that quicken and the bank use to communicate and communications are
> >encoded, you can't get any data from being in the middle, unless I'm
> >missing something.
> I generated a self-signed cert and added to the trust store on my Mac OS
> keychain. I was actually able to get away with a very manual man-in-the-middle
> using an "openssl s_server" command running on 433, modifying the /etc/hosts
> file to point back to my machine, and copy-pasting the request to curl, then
> copy-pasting the response.
> On Sat, Feb 6, 2021 at 8:45 PM Scott McRae <smcrae at parax.com> wrote:
>> I got this working in my software with some help for the info on this
>> list. Here is a write-up:
>> USAA's changes to their OFX interface
>> -------------------------------------
>> On 2020-01-26, USAA's previous OFX interface (
>> https://service2.usaa.com/ofx/OFXServlet) stopped working. It seems like
>> they switched to a new interface through a tech provider to replace their
>> previous login method (with your website credentials) to an app-specific ID
>> and password. This is a good move for security, but it was done without
>> notice, it seems, to anyone but Quicken.
>> From some internet searches, I found some people on the right track to
>> fixing this on the GNU Cash development mailing list:
>> https://lists.gnucash.org/pipermail/gnucash-devel/2021-January/045664.html
>> They were able to determine that USAA was:
>>  - using a new OFX endpoint:
>> https://df3cx-services.1fsapi.com/casm/usaa/access.ofx
>>  - using a new OFX Org ID: USAA Federal Savings Bank
>>  - using a new OFX FID: 67811
>> Additionally, someone on the USAA forums was about to extract and post
>> the link to generate an App ID and PIN:
>> source:
>> https://communities.usaa.com/t5/Finances/USAA-Creates-Quicken-Monopoly/td-p/243850/highlight/false
>> Authorization link: https://df3cx-services.1fsapi.com/casm/usaa/enroll
>> However, with a lot of trial and error I still wasn't able to hit this
>> new endpoint successfully. So I decided to give the devil his due and
>> temporarily got a Quicken subscription and setup an SSL man-in-the-middle.
>> The new OFX interface is *very* finicky, so you basically have to input
>> everything exactly the way it expects it. Here is an example of an account
>> listing query that works:
>> echo -en
>> Federal Savings
>> Bank\r\n<FID>67811\r\n</FI>\r\n<APPID>QMOFX\r\n<APPVER>2300\r\n<CLIENTUID>1955A543-B071-455E-A31E-73CC7C493D68\r\n</SONRQ>\r\n</SIGNONMSGSRQV1>\r\n<SIGNUPMSGSRQV1>\r\n<ACCTINFOTRNRQ>\r\n<TRNUID>e39add7d-2085-4504-b9ee-be37927de39c\r\n<ACCTINFORQ>\r\n<DTACCTUP>19900101\r\n</ACCTINFORQ>\r\n</ACCTINFOTRNRQ>\r\n</SIGNUPMSGSRQV1>\r\n</OFX>\r\n"
>> | curl -isS -X POST -H "Content-Type: application/x-ofx" -A InetClntApp/3.0
>> --data-binary @- https://df3cx-services.1fsapi.com/casm/usaa/access.ofx
>> Note you have to change the XXXXX and NNNNN to the App ID and PIN you get
>> from the link above.
>> Some things I've found through trial and error:
>>  - The OFX elements must be separated with "\r\n". This is dumb, but
>> true. No spaces. No simple "\n". Exactly "\r\n".
>>  - The APPID "QMOFX" and APPVER "QMOFX" work. Others I tried did not.
>>  - The CLIENTUID "1955A543-B071-455E-A31E-73CC7C493D68" works for me. It
>> must be uppercase. This might be particular to your account. If so, you can
>> find it looking at the OFX logs from Quicken.
>>  - TRNUID must be present, but an UUID will do.
>>  - DTACCTUP: The value "19900101" works. The value "19700101" does not.
>> The value "19900101000000" does not.
>>  - You need the "Content-Type: application/x-ofx" header
>>  - You need the User-Agent "InetClntApp/3.0". This is what Quicken for
>> Mac sends.
>> It also seems their gateway will under some conditions put your IP on a
>> ban list. If you are testing, you may want to spin up an AWS instance or
>> something. When you get on it, you'll start seeing an empty HTML page
>> response, like:
>> <html>
>> <head>
>> <META NAME="robots" CONTENT="noindex,nofollow">
>> <script
>> src="/_Incapsula_Resource?SWJIYLWA=5074a744e2e3d891814e9a2dace20bd4,719d34d31c8e3a6e6fffd425f7e032f3">
>> </script>
>> <body>
>> </body></html>
>> Valid queries will work from different source IPs when this happens.
>> Thanks to Bob White on the GNU Cash list and RDD! on the USAA Forums for
>> the breadcrumbs. No thanks to USAA for swapping out their functional
>> interface with absolutely no notice or documentation and pretending like
>> Quicken users are the only customers of any importance. Please just don't
>> break our software again... at least for awhile.
>> - Scott McRae

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