A flaw has been discovered in the security of 500 million mobile phones that could leave them vulnerable to attack, cyber researchers have said.
The Geneva-based International Telecommunications Union (ITU) claims that the bug, discovered by German firm Security Research Labs, could potentially enable hackers to remotely gain control of and also clone certain mobile SIM cards.
The ITU, the United Nations group that advises nations on cybersecurity, described the findings on Sunday as "hugely significant".
We have been able to consider the implications and provide guidance to those network operators and SIM vendors that may be impacted
Security Research Labs will describe the vulnerabilities of SIM cards at the Black Hat hacking conference that opens in Las Vegas on July 31.
"These findings [of Security Research Labs] show us where we could be heading in terms of cybersecurity risks," ITU Secretary-General Hamadoun Tour told the Reuters news agency.
He said the agency would notify telecommunications regulators and other government agencies in nearly 200 countries about the potential threat and also reach out to hundreds of mobile companies, academics and other industry experts.
A spokeswoman for the GSMA, which represents nearly 800 mobile operators worldwide, said it also reviewed the research.
"We have been able to consider the implications and provide guidance to those network operators and SIM vendors that may be impacted," Claire Cranton said.
Nicole Smith, a spokeswoman for Gemalto NV, the world's biggest maker of SIM cards, said her company supported GSMA's response.
Cracking SIM cards has long been the Holy Grail of hackers because the tiny devices are located in phones and allow operators to identify and authenticate subscribers as they use networks.
Karsten Nohl, the chief scientist who led the research team and will reveal the details at Black Hat, said the hacking only works on SIMs that use an old encryption technology known as DES.
Nohl said he conservatively estimates that at least 500 million phones are vulnerable to the attacks he will discuss at Black Hat.