cURL unable to use curl-ca-bundle.crt when accessing SSL - windows

Question

I'm on Windows attempting to use cURL using SSL, but running into certificate issues that I absolutely cannot figure out.
For example, here is an example of what I'm trying to run.
$ curl "https://google.com" --ntlm -v --negotiate -u USERNAME:PASSWORD --proxy "PROXY" --cert "c:\temp\curl-ca-bundle.crt"
* Adding handle: conn: 0x147ce88
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0x147ce88) send_pipe: 1, recv_pipe: 0
* About to connect() to proxy PROXY port 8080 (#0)
* Trying 192.168.134.80...
* Connected to PROXY (PROXY_IP) port 8080 (#0)
* Establish HTTP proxy tunnel to google.com:443
> CONNECT google.com:443 HTTP/1.1
> Host: google.com:443
> User-Agent: curl/7.30.0
> Proxy-Connection: Keep-Alive
>
< HTTP/1.1 200 Connection established
<
* Proxy replied OK to CONNECT request
* unable to use client certificate (no key found or wrong pass phrase?)
* Closing connection 0
curl: (58) unable to use client certificate (no key found or wrong pass phrase?)
Attempting to use --cacert instead of --cert yields the following message -
* Adding handle: conn: 0x130cdf8
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0x130cdf8) send_pipe: 1, recv_pipe: 0
* About to connect() to proxy PROXY port 8080 (#0)
* Trying 192.168.135.80...
* Connected to PROXY (PROXY_IP) port 8080 (#0)
* Establish HTTP proxy tunnel to google.com:443
> CONNECT google.com:443 HTTP/1.1
> Host: google.com:443
> User-Agent: curl/7.30.0
> Proxy-Connection: Keep-Alive
>
< HTTP/1.1 200 Connection established
<
* Proxy replied OK to CONNECT request
* successfully set certificate verify locations:
* CAfile: c:\temp\curl-ca-bundle.crt
CApath: none
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS alert, Server hello (2):
* SSL certificate problem: unable to get local issuer certificate
* Closing connection 0
curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: http://curl.haxx.se/docs/sslcerts.html
curl performs SSL certificate verification by default, using a "bundle"
of Certificate Authority (CA) public keys (CA certs). If the default
bundle file isn't adequate, you can specify an alternate file
using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
the bundle, the certificate verification probably failed due to a
problem with the certificate (it might be expired, or the name might
not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use the
-k (or --insecure) option.
The curl-ca-bundle.crt I have is from here, which was update a few minutes ago. I ensured the file is not blocked by Windows.
For what it's worth, I'm behind a corporate proxy and firewall. I have read everything I could find on this issue and don't know what to do next. I do realize I can ignore SSL, but would like to avoid this at all costs.

Answer 1

For what it's worth, I'm behind a corporate proxy and firewall. I have read everything I could find on this issue and don't know what to do next. I do realize I can ignore SSL, but would like to avoid this at all costs.
I would suggest the firewall does SSL interception, i.e. it works as a man-in-the-middle. To inspect encrypted connections it will split it into two encrypted connections, but of course it will not be able to sign the connection between browser and proxy with the original certificate. Thus it will create a new certificate, signed by a CA specific to the firewall. You need to add this CA to your CA bundle or the verification will fail.
For more details you might try to access the target site with a web browser and check the CA which signed the servers certificate or ask your system administrator for details of the SSL interception.