Experts today warned it's 'possible' Tuesday's AT&T outage could have been caused by a cyber attack on US cell phone infrastructure.
Customers in at least 24 states were impacted by the outage, which included issues with making calls to people on other networks and trouble accessing the internet.
But when police reported that customers were having trouble making emergency 911 calls, it raised suspicion that something nefarious was going on.
Cybersecurity experts told DailyMail.com that when 'for-profit threat actors are targeting any opportunistic vulnerabilities; anything is possible.'
However, an AT&T spokesperson told DailyMail.com that 'yesterday’s issue was not the result of a cyber-attack,' and was instead 'related to interoperability between carriers, which has since been resolved.'
It comes after a major attack .
AT&T customers have reported issues making 911 calls in multiple US states. At least 24 states are experiencing problems that started around 12:26pm ET
Cybercriminals view 911 call centers as attractive targets because of the large amount of sensitive data the systems include.
Accessing that information is a major problem for public safety, meaning the hackers believe the Emergency Service Sector (EES) would be more enticed to pay ransoms to ensure the information remains safe and to get the systems back up and running.
Customers complained that 911 wasn't working yesterday after AT&T mistakenly sent a wireless impact notification to emergency call centers, but a company spokesperson said the services had been operating normally.
The spokesperson added: 'We’re working to correct a wireless impact notification that was sent in error to 9-1-1 call centers.'
Although AT&T said the outage wasn't caused by a hacker, Dave Hatter, a cybersecurity consultant for Intrust IT told DailyMail.com he has 'seen nothing so far that would rule out a cyberattack.'
'While any complex system can have issues at any time, it does seem unusual for a long-standing and well respected company like AT&T to have two prolonged outages in relatively short period of time,' he said.
With over 241 million customers, 'AT&T is a highly desirable target because of its size and coverage,' said Alex Holden, the founder and chief information security officer of Hold Security, a threat intelligence services company that monitors the dark web.
'We should learn from the example from the 2023 Russian cyber attack against Ukrainian largest cellular services provider Kyivstar,' he added.
The hack knocked out Ukraine's biggest cell phone operator for 24 million users aimed to gather intelligence.
'This attack is a big message, a big warning, not only to Ukraine, but for the whole Western world to understand that no one is actually untouchable,' Illia Vitiuk, head of the Security Service of Ukraine's (SBU) cybersecurity department told Reuters in December.
But Holden told DailyMail.com he believes it's unlikely that yesterday's outage was the result of a cyberattack because 'nation-state threat actors are not seeking to cause severe service outages as it may lead to an escalation of tensions between nations or even a war.'
Despite this one reassurance, the AT&T outages highlight how vulnerable the US is to attacks, Alex Hamerstone the advisory solutions director at the cybersecurity company, TrustedSec, told DailyMail.com.
'An attack designed to overwhelm networks, not just damage them, could be very impactful,' he said because by taking out phone calls and the internet, people would lose access to much-needed medical care and transportation.
Many users threatened to leave America's biggest phone provider after yesterday's outage and expressed outrage that they'll be required to pay their full bill after the second outage in less than four months.
AT&T's outages were spread out with issues reported in Tampa, Atlanta, Houston, Los Angeles and Phoenix
Hackers exploit mobile phone software and infrastructure to steal valuable data and by targeting the large companies, they could receive lucrative ransomware profits.
AT&T has suffered two prolonged outages this year that impacted tens of thousands of users across the US.
The company was also hit by a major data breach in 2021 when hackers claimed they stole customer data from the service provider and threatened to sell the information, an allegation that AT&T denied.
There is an extreme amount of effort that goes into maintaining cell phone infrastructure worldwide, according to Hamerstone.
'In fact, I think many people would end up being surprised that things work as often as they do,' he told DailyMail.com.
Maintaining the cell phone infrastructure is a two-tiered process, Hamerstone said, because the workers need to keep the existing system functioning while also continuously improving, updating and expanding the systems, networks and equipment.
This also includes improving the infrastructure's resilience to security threats.
He clarified that a cyberattack has the possibility to cause a cell phone outage at any time, although 'it is not generally the most likely.'
The major outage in February that disrupted not just AT&T, but also Verizon and Cricket Wireless, prompting the Federal Communications Commission (FCC) to open an investigation into whether it was caused by a cyber attack.
In April, the FCC opened an additional cybersecurity investigation after people in four states including South Dakota, Nevada, Texas and Nebraska couldn't make 911 calls.
'There are many things that can lead to service disruption which can run the gamut from issues with physical infrastructure, challenges with upgrading underlying code and human error,' Hamerstone said, adding: 'Service disruptions are also much more noticeable as more and more of our daily lives depend on wireless communication.'
