The FBI issued a warning on February 17 about the dire consequences of Telephony Denial of Service (TDoS) attacks, while also providing necessary measures to mitigate the impact. In particular, the police agency pointed out that attacks on emergency services can cost lives.
TDoS attacks are manual or automated malicious attempts by hackers to render telephone systems unavailable by blocking incoming and outgoing calls. This could be fatal when it comes to services like 911 or other similar emergency call centers.
Hackers carry out these types of attacks for a variety of reasons, such as hacktivism, financial gain, or harassment. While hacktivists may abuse important services to promote their social or political beliefs, they have also carried out telephony denial-of-service (TDoS) attacks and aimed at blackmailing government and private organizations.
According to the FBI, there has been a significant increase in telephone denial of service (TDoS) attacks on emergency services. In TDoS attacks, hackers prevent emergency services phone lines from receiving calls from people in need of help, so they cannot respond.
As BleepingComputer reports, a separate alert sent to public safety answering points (PSAPs), emergency communications centers and personnel in March 2013 noted that “government/emergency services are allegedly being targeted due to the need for operational phone lines.”
However, in its current warning, the FBI added that malicious actors are providing TDoS services and tools to attackers with varying levels of experience, which significantly reduces the skill level required to launch such attacks.
Importantly, TDoS attacks are difficult to detect, as attackers spoof the caller ID of each call. In some cases, they even choose to spoof police phone numbers. This makes it almost impossible to distinguish between legitimate and malicious calls.
As previously mentioned, the FBI's warning includes a list of steps to take before and during TDoS attacks, as well as information on how to report attacks to authorities. The FBI also shared information on how to prepare for potential 911 outages and disruptions sothat they don't cost lives. Specifically, the FBI recommends the following:
- Before an emergency occurs, contact your local emergency services for information on how to request service in the event of a 911 outage. Find out if text-to-911 is available in your area.
- Have emergency contact numbers readily available for fire, rescue, and law enforcement in the event of a 911 outage.
- Sign up for automatic alerts from your area to be notified of emergencies in your area via text, phone, or email.
- Identify sites and follow social media for emergency responders in your area for emergency awareness.
