A United Nations (UN) group that advises countries on online security plans to send out an alert about significant vulnerabilities in mobile phone technology that could potentially enable hackers to remotely attack at least half a billion SIM cards.

According to the report, a German firm discovered the bug on the SIM cards which allows hackers to remotely gain control of and also clone certain mobile SIM cards.

The hackers have the capability to use compromised SIMs to commit financial crimes or engage in electronic espionage, according to Berlin’s Security Research Labs, which will describe the vulnerabilities at the Black Hat hacking conference that opens in Las Vegas on July 31.

The UN’s Geneva-based International Telecommunications Union, which has reviewed the research, described it as “hugely significant.”

“These findings show us where we could be heading in terms of cyber-security risks,” ITU Secretary General Hamadoun Touré told Reuters.

The ITU he said 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.

It is thought that many of the 200 countries mentioned in the report are in Africa.

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,” said GSMA spokeswoman Claire Cranton.

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.

Once a hacker copies a SIM, it can be used to make calls and send text messages impersonating the owner of the phone, according to Karsten Nohl, the chief scientist who led the research team.

Nohl said he conservatively estimates that at least 500 million phones are vulnerable to the attacks he will discuss at Black Hat. He added that the number could grow if other researchers start looking into the issue and find other ways to exploit the same class of vulnerabilities.

The ITU estimates some 6 billion mobile phones are in use worldwide. It plans to work with the industry to identify how to protect vulnerable devices from attack, Touré said.

“If you have a MasterCard number or PayPal data on the phone, we get that too,” if it is stored on the SIM, he said.

The newly identified attack method only grants access to data stored on the SIM, which means payment applications that store their secrets outside of the SIM card are not vulnerable to this particular hacking approach.

The mobile industry has spent several decades defining common identification and security standards for SIMs to protect data for mobile payment systems and credit card numbers. SIMs are also capable of running applications (apps).

Nohl said Security Research Labs found mobile operators in many countries whose phones were vulnerable, but declined to identify them. He said mobile phone users in Africa could be among the most vulnerable because banking is widely done via mobile payment systems with credentials stored on SIMs.

All types of phones are vulnerable, including iPhones from Apple, phones that run Google’s Android software and BlackBerry smartphones, he said.