Russian soldiers participating in SMO reported multiple times that after they exchange texts and photos with their relatives in WhatsApp, that information ends up in Ukrainian military HQs next day. With photos. And later used, for example, to harass the relatives of the soldier.
Could be some other mechanism (e.g. Google Drive or some other kind of malware), hard to be sure in the world, where since 2011 Snowden's revelations, bugs are placed my NSA and CIA everywhere, starting from hardware and firmware.
Russian soldiers chatting with their family know what precisely happens in the Ukrainian military HQ the next day? That sounds too crazy to be even remotely true, and too convenient a story ("they are harassing your family, go murder someone").
After arrest of Durov in France I think the same. Doesn't change the fact that any single Russian soldier is not using WhatsApp. It's considered compromised with very convincing evidence, along with some other apps (I don't remember all the names, possible to find in military news channels if you know Russian).
There were evidence of leaks of soldiers' messages from WhatsApp.
I do not know for sure if there are leaks from Telegram, but I think that Durov was pressed for enabling backdoors for CIA when he was arrested in France.
It's not like there's a registry of compromised apps in Russia that is available to public. When there were WhatsApp leaks it was widely published on Russian news channels, that's why I know about it and tell everyone to not trust WhatsApp.
But I don't closely follow every news item from the front, I know that some other apps are also considered compromised (mainly some navigation apps), but I don't know the whole list or if Telegram is being used on the front.
I guess the safest option is to not use telephone at all at war, since there are probably backdoors everywhere starting from cell modem firmware. I guess that since about middle-end of 2022 all military personnel has the same opinion and stopped using smartphones altogether or use them in flight mode with communications disabled.
> but I think that Durov was pressed for enabling backdoors for CIA when he was arrested in France.
Durov was pressed from every side from the beginning, no doubts about this. But CIA or FSB cannot demand it legally even with secret court orders. There were news that since arrest in France he started providing some info on criminals. Not sure how far did he go. But it's good to know that Whatsup is fully cooperating with governments even when they don't have to. Putting people at risk.
As for smartphones, there are so many security holes that it's impossible to secure. Many harmless applications are calling home, pictures are geo-targeted, cell towers can request info from connected phones, every update can turn OS or app into trojan. If infected it's a perfect audio and video collection device. Put together with soldiers' IDs it shows where the unit is. Add to that CIA and alike working with weakening everyone's security and getting priority access to sensitive information.
Could be some other mechanism (e.g. Google Drive or some other kind of malware), hard to be sure in the world, where since 2011 Snowden's revelations, bugs are placed my NSA and CIA everywhere, starting from hardware and firmware.