"Surveillance systems that track the locations of cellphone users and spy on their calls, texts and data streams are being turned against Americans as they roam the country and the world, say security experts and U.S. officials. Federal officials acknowledged the privacy risk to Americans in a previously undisclosed letter from the Department of Homeland Security ... [to a U.S. Senator] last week, saying they had received reports that 'nefarious actors may have exploited' global cellular networks 'to target the communications of American citizens.' The letter, dated May 22 and obtained by The Washington Post, described surveillance systems that tap into a global messaging system that allows cellular customers to move from network to network as they travel. The decades-old messaging system, called SS7, has little security, allowing intelligence agencies and some criminal gangs to spy on unwitting targets — based on nothing more than their cellphone numbers..." https://www.washingtonpost.com/busi...070ef53f315_story.html?utm_term=.7208a9fa0b35
SS7 has so little security that, if you're a person of interest, almost anybody knowing your mobile number can spy on you. It's probably more insecure than unencrypted emails are.
Stingray phone stalker tech used near White House, SS7 abused to steal US citizens' data June 1, 2018 http://www.theregister.co.uk/2018/06/01/wyden_ss7_stingray_fcc_homeland_security/
How a 40-Year-Old Mobile Security Flaw Puts Consumers at Risk https://securityintelligence.com/news/how-a-40-year-old-mobile-security-flaw-puts-consumers-at-risk/
They mean "unauthorized cybercriminals", I think I mean, we know that telecom providers sell data to third parties that we might as well consider to be cybercriminals.
Federal Judge scolds FBI agent for improper stingray use July 18, 2018 https://www.scmagazine.com/federal-judge-scolds-fbi-agent-for-improper-stingray-use/article/781734/
In Cellphone Spying, Stingrays Are A Red Herring October 2, 2018 https://www.scmagazine.com/home/news/in-cellphone-spying-stingrays-are-a-red-herring/
Having worked on POTS systems from their early electronic days, I can tell you for a fact that they were designed from the outset to permit "lawful intercept" and on the presumption that the PTTs (which were effectively offshoots of government) were trusted agents in doing so. That this illustrates the harm of attempting to force intercept on internet communications and attacking end to end encryption seems to escape them as a mechanism of harm to their own citizens. My take is that they are both lying and incompetent by the way. Very competent in getting some people to believe green is red or something. The old Lincoln phrase comes to mind.
Security Vulnerabilities in Cell Phone Systems https://www.schneier.com/blog/archives/2019/01/security_vulner_19.html