Security software corrupts messages

Soot

Hello,

I have developed a software receiving a stream of prices from a server running with LightStreamer 5.

Since a few weeks some users of my software are noticing, that sometimes wrong prices are received. This effect is really rare and happens in average for one or two price messages per day. After some research it seems, that in such cases the installed security software is manipulating the price messages. By doing so really low/high numbers are appearing in the fields the prices are read from.

One of those security softwares is Avira Antivir. By uninstalling it the issue could be fixed.

Are you aware of this issue? Is there another way to fix it?

Thanks in advance!

Best regards,

Soot

Giuseppe Corti

Hi Soot,

Please could you confirm that the communication with the Lightstreamer server in not secure?

However, if an antivirus software intercepts the data flow and randomly modifies messages before your client receives them, it is something we can not avoid.
What is strange is that such behavior should impact other services and not just Lightstreamer.
Our communication protocol is completely agnostic on the representation of data, which interpretation is completely free between the Data Adapter and the client.
Furthermore a randomic modification of our message with very high probability should break the simple communication protocol, and make the message unrecognizable by the client.
Only have a scale error on prices is something the puzzled me a lot. But to investigate this we should have a pre and post antivir flow capture.

Regards,
Giuseppe

Soot

Hi Giuseppe,

The communication with the LightStreamer server is via SSL. So I guess, the security software is proxying the connection to the web server to be able to scan for threats.

For affected clients our software is quite often erroring, that it can't find the subscription id in the message. So it can't allocate a received message to an instrument the prices are for.

How we can check, if a message was modified? Is the protocol offering some checks?

Best regards,

Soot

Giuseppe Corti

Hi Soot,

Please could you confirm that your software directly implements the network protocol, without leveraging one of our ready-made client libraries? If so, could you specify the version and if is the new TLCP.

From your description, it seems to me that messages rather than corrupt are fragmented and not reconstructed properly.

Regards,
Giuseppe

Soot

Hi Giuseppe,

The software is using the libcurl library (version 7.47.0) to connect to the LightStreamer server.

Could you please point me to an example how to verify the completion and correct syntax of a received message?

Best regards,

Soot

Giuseppe Corti

Hi Soot,

Ok, I suppose that you implement by the libcurl our Network Protocol; and from the Lightstreamer servr version you mentioned I also suppose that is the old version.
The protocol is described in this document: https://www.lightstreamer.com/repo/distros/Lightstreamer_Allegro-Presto-Vivace_5_1_2_Colosseo_20140722.zip%23/Lightstreamer/DOCS-SDKs/sdk_client_generic/doc/Network%20Protocol%20Tutorial.pdf
And in particular the update messages are discussed in the 4.5.1 section (page 28).

Regards,
Giuseppe

Hubbell

How beginner-friendly is that tutorial in your opinion, Giuseppe?

Giuseppe Corti

Hi Hubbell,

Well, actually the "Network Protocol Tutarial" document maybe is not the best resource for a true Lightstreamer beginner.
Although enriched by the definition of basic concepts and several examples, it is rather a document defining the specifications of the protocol. Indeed in my opinion what was required by this discussion.

For a Lightstreamer beginners the best entry-level resources are:

- "General Concepts" considered as a preliminary reading (https://www.lightstreamer.com/docs/base/General%20Concepts.pdf);

- The "Hello World with Lightstreamer" example series, example with full desciption and source code (https://github.com/Lightstreamer?utf8=%E2%9C%93&q=HelloWorld&type=&language=);

- The "Quickstart" series, basic introduction to the main client APIs available (https://github.com/Lightstreamer?utf8=%E2%9C%93&q=Quickstart&type=&language=).

That said, I know a few friends of mine who still prefer to start with a cold and precise description of the specifications, but I must admit that they are not so many.

Please let us know any other comments or suggestions.

Regards,
Giuseppe