sauce-connect: add Traffic Inspection article (#2854)

Add article how to use Wireshark with sc.

docs/secure-connections/sauce-connect-5/inspecting.md

@@ -0,0 +1,166 @@
+---
+id: inspecting
+title: Traffic Inspection
+---
+
+This document describes how to inspect Sauce Connect 5 tunnel traffic using Wireshark or other network analysis tools.
+This technique allows you to decrypt SSL/TLS traffic by using TLS keys logged by the Sauce Connect.
+It does not require use of third-party proxies to reencrypt the traffic.
+
+:::note
+Inspecting tunnel traffic is available in **Sauce Connect Proxy 5.2** and later.
+:::
+
+## Prerequisites
+
+- [Wireshark](https://www.wireshark.org) must be installed on your machine.
+  Make sure you have the Wireshark command line tool `tshark` available.
+- [Sauce Connect Proxy 5](/secure-connections/sauce-connect-5/installation) must be installed and configured.
+
+## TLS key logging
+
+There is more than one way to enable TLS key logging in Sauce Connect Proxy 5:
+
+* Using the `SSLKEYLOGFILE=<path>` environment variable -
+  enables logging of all TLS keys to the specified file,
+  this includes both tunnel connections and connections to upstream servers.
+* Using the `--tunnel-tls-keylog-file=<path>` flag - 
+  enables logging of TLS keys for tunnel connections to Sauce Labs servers only.
+* Using the `--http-tls-keylog-file=<path>` flag -
+  enables logging of TLS keys for both tunnel connections and connections to upstream servers.
+
+The following example demonstrates how to enable TLS key logging for tunnel connection only:
+
+Command line:
+
+```bash
+sc run ... --tunnel-tls-keylog-file=/path/to/sslkeylog.log
+```
+
+Configuration file:
+
+```yaml
+tunnel-tls-keylog-file: /path/to/sslkeylog.log
+```
+
+## TLS resigning
+
+Setting `SSLKEYLOGFILE` will allow you to inspect HTTP requests made by the tunnel client.
+If you want to inspect HTTPS requests, you need to run Sauce Connect Proxy with TLS resigning enabled. 
+This is because Sauce Connect Proxy does not have access to the client's private keys, which are required to decrypt HTTPS traffic.
+
+See [--tls-resign-domains](/dev/cli/sauce-connect-5/run/#tls-resign-domains) flag for more information on how to enable TLS resigning.
+
+## Traffic capture
+
+Follow these steps to inspect tunnel traffic using Wireshark:
+
+1. Start capturing traffic using `tshark` before starting the Sauce Connect Proxy:
+
+   ```bash
+   tshark -f "tcp port 443" -o "tls.keylog_file:/path/to/sslkeylog.log" -Y http2 -O http2 
+   ```
+   Replace `/path/to/sslkeylog.log` with the path to the file where the TLS keys are logged.
+   Note that if tshark is started after the Sauce Connect Proxy, it will not be able to decrypt the traffic.
+
+   The `tshark` command would try to guess the interface to capture traffic from.
+   You can list available interfaces using `tshark -D`,
+   and specify the interface using the `-i` flag ex. `tshark -i eth0 ...`.
+
+1. Start the Sauce Connect Proxy with TLS key logging and TLS resigning enabled:
+
+   ```bash
+   sc run ... --tunnel-tls-keylog-file: /path/to/sslkeylog.log --tls-resign-domains all
+   ```
+1. You should see decrypted HTTP/2 frames in the output of `tshark` similar to the following:
+
+   ```
+   Frame 49414: 105 bytes on wire (840 bits), 105 bytes captured (840 bits) on interface en4, id 0
+   Ethernet II, Src: CompalBroadb_e8:b4:78 (ac:22:05:e8:b4:78), Dst: BelkinIntern_cd:b6:0b (e8:9f:80:cd:b6:0b)
+   Internet Protocol Version 4, Src: 185.94.26.247, Dst: 192.168.0.206
+   Transmission Control Protocol, Src Port: 443, Dst Port: 53736, Seq: 12230, Ack: 20202, Len: 39
+   Transport Layer Security
+   HyperText Transfer Protocol 2
+       Stream: PING, Stream ID: 0, Length 8
+           Length: 8
+           Type: PING (6)
+           Flags: 0x00
+               0000 000. = Unused: 0x00
+               .... ...0 = ACK: False
+           0... .... .... .... .... .... .... .... = Reserved: 0x0
+           .000 0000 0000 0000 0000 0000 0000 0000 = Stream Identifier: 0
+           Ping: 9db0139a0702fc8b
+   
+   Frame 49731: 155 bytes on wire (1240 bits), 155 bytes captured (1240 bits) on interface en4, id 0
+   Ethernet II, Src: CompalBroadb_e8:b4:78 (ac:22:05:e8:b4:78), Dst: BelkinIntern_cd:b6:0b (e8:9f:80:cd:b6:0b)
+   Internet Protocol Version 4, Src: 185.94.26.247, Dst: 192.168.0.206
+   Transmission Control Protocol, Src Port: 443, Dst Port: 53735, Seq: 19179, Ack: 534008, Len: 89
+   Transport Layer Security
+   HyperText Transfer Protocol 2
+       Stream: HEADERS, Stream ID: 29, Length 58
+           Length: 58
+           Type: HEADERS (1)
+           Flags: 0x04, End Headers
+               00.0 ..0. = Unused: 0x00
+               ..0. .... = Priority: False
+               .... 0... = Padded: False
+               .... .1.. = End Headers: True
+               .... ...0 = End Stream: False
+           0... .... .... .... .... .... .... .... = Reserved: 0x0
+           .000 0000 0000 0000 0000 0000 0001 1101 = Stream Identifier: 29
+           [Pad Length: 0]
+           Header Block Fragment: 4199415293553216f06a9790691af498961d07952b90f4dc69a67fdae4d97f0299415293553216f06a9790691af498961d07952b90f4dc69a67f
+           [Header Length: 206]
+           [Header Count: 5]
+           Header: :authority: settings-win.data.microsoft.com:443
+               Name Length: 10
+               Name: :authority
+               Value Length: 35
+               Value: settings-win.data.microsoft.com:443
+               :authority: settings-win.data.microsoft.com:443
+               [Unescaped: settings-win.data.microsoft.com:443]
+               Representation: Literal Header Field with Incremental Indexing - Indexed Name
+               Index: 1
+   ...
+   ```
+
+### Customizing display filters
+
+WireShark provides a powerful display filter language that allows you to filter the traffic you want to inspect.
+For example, to capture only [HTTP/2 HEADERS frames](https://httpwg.org/specs/rfc7540.html#HEADERS) in a format that is easier to further process, you can use the following command:
+
+```bash
+tshark -f "tcp port 443" -o "tls.keylog_file:/path/to/sslkeylog.log" \
+-Y "http2.type == 1" -T fields -e frame.number -e http2.header.name -e http2.header.value
+```
+
+Output:
+
+```
+2889	:authority,:method,:path,:scheme,user-agent,accept,priority,x-forwarded-for,sl-forwarded-proto,x-forwarded-proto,sl-forwarded-host,x-forwarded-host,via,x-forwarded-url,accept-language,accept-encoding,content-type,pragma,cache-control,content-length	r11.o.lencr.org,POST,/,http,Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0,*/*,u=2,10.113.32.170,http,http,r11.o.lencr.org,r11.o.lencr.org,1.1 sc_server-dfcd2679b772ba704ff6,http://r11.o.lencr.org/,en-US,en;q=0.5,gzip, deflate,application/ocsp-request,no-cache,no-cache,85
+2918	:authority,:method,:path,:scheme,x-forwarded-for,cache-control,x-forwarded-url,via,sl-forwarded-proto,x-forwarded-host,accept,accept-encoding,content-type,priority,sl-forwarded-host,user-agent,accept-language,x-forwarded-proto,pragma,content-length	r10.o.lencr.org,POST,/,http,10.113.32.170,no-cache,http://r10.o.lencr.org/,1.1 sc_server-dfcd2679b772ba704ff6,http,r10.o.lencr.org,*/*,gzip, deflate,application/ocsp-request,u=2,r10.o.lencr.org,Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0,en-US,en;q=0.5,http,no-cache,85
+2924	:authority,:method,:path,:scheme,pragma,via,x-forwarded-host,accept,x-forwarded-url,priority,x-forwarded-for,sl-forwarded-proto,sl-forwarded-host,user-agent,accept-language,accept-encoding,content-type,cache-control,x-forwarded-proto,content-length	r10.o.lencr.org,POST,/,http,no-cache,1.1 sc_server-dfcd2679b772ba704ff6,r10.o.lencr.org,*/*,http://r10.o.lencr.org/,u=2,10.113.32.170,http,r10.o.lencr.org,Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0,en-US,en;q=0.5,gzip, deflate,application/ocsp-request,no-cache,http,85
+2962	:authority,:method,sl-forwarded-proto,sl-forwarded-host,user-agent,via	saucedemo.com:443,GET,,saucedemo.com:443,Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0,1.1 sc_server-dfcd2679b772ba704ff6
+...
+```
+
+Check [Wireshark display filter reference](https://www.wireshark.org/docs/dfref/h/http2.html) for more information on available filters for HTTP/2. 
+
+### Using tcpdump
+
+You can also use `tcpdump` to capture traffic and save it to a file for later analysis.
+Make sure to start `tcpdump` before starting the Sauce Connect Proxy.
+The captured pcap file can be opened in `tshark` for inspection using the following command:
+
+```bash
+tshark -r /path/to/capture.pcap -o "tls.keylog_file:/path/to/sslkeylog.log" -Y http2 ...
+```
+
+This is particularly useful to experiment with different display filters and inspect the traffic in more detail.
+
+## Additional resources
+
+* [Display Filter Reference: HyperText Transfer Protocol 2](https://www.wireshark.org/docs/dfref/h/http2.html)
+* [Wireshark TLS](https://wiki.wireshark.org/TLS)
+* [Wireshark tcpdump](https://www.wireshark.org/docs/wsug_html_chunked/AppToolstcpdump.html)
+* [HTTP/2 spec](https://httpwg.org/specs/rfc7540.html)

sidebars.js

@@ -1042,6 +1042,7 @@ module.exports = {
                         },
                         'secure-connections/sauce-connect-5/logging',
                         'secure-connections/sauce-connect-5/monitoring',
+                        'secure-connections/sauce-connect-5/inspecting',
                         {
                             type: 'category',
                             label: 'Setup and Configuration',