Telephony remains an essential tool for communication in a variety of industries, including emergency response services, financial organizations, healthcare systems, and critical infrastructure. Many organizations in these sectors have seen a rise in telephony denial of service attacks, or TDoS attacks. Similar to Distributed Denial of Service (DDoS) attacks on data networks, TDoS attacks overwhelm a target’s telephone system, rendering telephony services unavailable for legitimate users.
What Are TDoS Attacks
TDoS attacks are designed to make a telephone system unavailable to intended users by preventing incoming or outgoing calls. These attacks flood an organization’s phone system with excessive call traffic and keep these calls active for as long as possible to overwhelm the system. By tying up all the available lines and resources, TDoS attacks effectively block any legitimate calls from getting through.
Why TDoS Attacks Occur
TDoS attacks may be motivated by several factors.
Financial Gain: Cyber criminals may use TDoS attacks to extort money from a targeted organization by threatening to continue or escalate the attack unless a payment is made. This type of threat can be especially effective with businesses where the cost of disruption far outweighs the ransom demanded by hackers.
Corporate Sabotage: An organization might initiate a TDoS attack to disrupt a competitor’s ability to serve customers and to damage the target’s reputation.
Ideological Purposes: Some TDoS attacks are carried out by hacktivists against organizations they believe are causing harm or acting unethically. These attacks typically seek to draw attention to a cause by disrupting communication channels in a public way.
Retaliation: In some instances, discredited former employees or unhappy clients may use TDoS attacks to harass and disrupt a business with which they have a grudge.
The Anatomy of a TDoS Attack
TDoS attacks may range from simple campaigns that use a single origination point and limited call number spoofing to more complex attacks that rely on sophisticated spoofing and distributed origination. Most rely on automation to generate a large volume of calls, though some attacks have leveraged social networks like Facebook or Twitter to persuade enough individuals to unwittingly participate in TDoS campaigns.
Tools and Techniques of TDoS Attacks
Attackers typically conduct TDoS campaigns using one or more of the following techniques.
Caller ID Spoofing: To evade discovery, attackers mask the origin of their calls by spoofing the caller ID number, making it more difficult to trace and identify.
Botnets: Attackers frequently use a botnet — a remotely controlled network of infected computers, phones, and other devices — to initiate and sustain a high volume of calls.
Malware: By duping a user into clicking on a link that downloads malware, attackers may cause smartphones or softphones to continuously dial a target’s number.
SIP-Based Call Generators: These technologies use software to make automated calls and enable attackers to spoof the calling number and play an audio message when the call is answered.
How TDoS Attacks Affect Organizations
TDoS attacks can cause severe disruption, crippling operations that rely on telephone connections to communicate with customers. For this reason, TDoS attacks typically are directed organizations with critical, public-facing contact centers. Emergency services like 911 are often a prime target, as the urgent need to restore service makes organizations more likely to pay a ransom. Healthcare organizations, financial services, and organizations that operate critical infrastructure are also frequent victims.
The Potential Impact of TDoS Attacks
TDoS campaigns can have serious and far-reaching consequences for victim organizations.
Disruption of Essential Communication: Organizations that rely on telephony for critical services, customer support, sales, and other essential functions will be unable to deliver the services during attack.
Financial Loss: In addition to potential ransom payments, the financial repercussions of a TDoS attack include lost sales, lost productivity, and compensation for dissatisfied customers. Additionally, the cost to mitigate the attack and restore normal operations can be significant.
Reputational Damage: When telephone services are disrupted for a prolonged period, it may substantially damage an organization’s reputation. In highly competitive industries, a temporary inability to reach the organization may cause customers to have a long-lasting negative perception and to turn to other companies for their needs.
Increased Cost: The additional security measures and technical support required to combat TDoS threats can be costly, especially for small and medium-sized businesses with limited resources.
Strategies for Preventing TDoS Attacks
Preventing attacks requires a multilayered approach that combines several effective TDoS protection measures.
Session Border Controllers (SBCs): SBCs provide security for SIP trunking and offer basic blacklisting and white listing capabilities that can help to defend against TDoS attacks. However, SBCs are not effective against more complex forms of TDoS.
Redundancy and Load-Balancing: These capabilities redistribute call traffic to minimize the impact of an attack on one system.
Call Authentication Protocols: Protocols like STIR/SHAKEN may help to prevent caller ID spoofing, which is an essential part of many TDoS attacks.
Real-Time Monitoring and Analytics: Tools that quickly detect abnormal traffic patterns may provide early detection of TDoS attacks, allowing organizations to respond quickly and limit damage.
Incident Response Plan: Incident response plans enable organizations to quickly take steps to mitigate the attack, restore service, and communicate with stakeholders.
SecureLogix: Solutions for Mitigating TDoS Attacks
As a pioneer of call security technology, SecureLogix offers proven solutions and the most skilled team in the industry to help mitigate TDoS attacks and other telephony threats. SecureLogix is the only vendor with a single set of unified solutions for all the security and call trust issues that threaten the customer experience. It’s no wonder that some of the world’s largest and most complex contact centers and voice networks rely on SecureLogix to protect their telephony systems against a wide range of threats.
SecureLogix provides protection against TDoS attacks at multiple levels. Our solutions address the evolving versions of TDoS attacks, and we are working with the Department of Homeland Security (DHS) to address more complex attacks expected in the future.
Call Defense™ System
SecureLogix Call Defense™ System sits at the edge of your voice network to reduce unwanted calls by sorting good traffic from bad in real time.
Key features
Call Firewall: Provides enterprise-wide call visibility and unified security policy enforcement. Prevents malicious calls and attacks with alerting, blocking, and/or redirection.
Call Intrusion Prevention (IPS): Detects call pattern attacks, identifies anomalies, and enforces limits on call volume threshold and traffic velocity.
Reporting Forensics: Provides insight into voice network usage and CDR analytics with all attack/ fraud forensics.
Call Secure™ Managed Service
This SecureLogix solution combines the power of cutting-edge technology with the most experienced call security service team in the industry. Delivered and managed by a team of SecureLogix experts, Call Secure™ Managed Service provides professionally managed voice firewall security policy construction, monitoring, and enforcement along with regular managerial and executive level reporting.
Key benefits
Protect against voice network attacks (SIP security)
Proactive monitoring of new attacks and malicious calls
Protection against call fraud, spoofing, and robocalls
Minimize call spam and unwanted nuisance calls
TrueCall™ Spoofing Protection Service
In addition to affecting target organizations, TDoS attacks can have a negative impact on businesses whose phone numbers are spoofed as part of the attack. SecureLogix TrueCall™ identifies and blocks spoofed calls attempting to use your corporate calling numbers to impersonate your brand. This network API-integrated spoofed-call filtering service is the strongest and most secure approach to spoofing prevention in the industry.
FAQ
Q: What is a TDoS attack?
TDoS attack, or Telephony Denial of Service attack, is an attack that targets an organization’s phone system by overwhelming it with a high volume of fake or malicious calls. The goal is to clog the lines so legitimate calls cannot get through, causing disruption to communication services.
Q: How long does a TDoS attack typically last?
The duration of a TDoS attack can vary from a few minutes to several hours or even days, depending on the attacker’s resources and objectives.
Q: What are some early warning signs of a TDoS attack?
Early warning signs include an unusual spike in call volume, many calls with very short or long durations, and calls originating from suspicious or spoofed numbers. Monitoring these patterns in real-time can help detect an attack in its early stages.
Q: What should I do if my organization is experiencing a TDoS attack?
If you suspect a TDoS attack, notify your IT and telephony security teams immediately. They can implement measures like rate limiting, call filtering, and blocking of suspicious numbers. It’s also essential to have an incident response plan in place, allowing for quick escalation and coordination with your telecommunications provider to help mitigate the attack.
Q: Can my telecom provider help mitigate a TDoS attack?
Yes, many telecommunications providers offer support in mitigating TDoS attacks. They can assist with blocking malicious traffic, rerouting calls, or temporarily enabling rate limits to help prevent the attack from affecting your organization’s critical operations. However, some service providers lack the ability to respond quickly and do not offer adequate defenses against more sophisticated attacks.
Q: How does caller ID spoofing affect TDoS attacks?
Caller ID spoofing enables attackers to disguise the origin of the call, making it look like the call is coming from a legitimate number. This tactic makes it harder for organizations to detect and block malicious calls, as calls appear to come from varied, seemingly legitimate sources.
Q: Can a TDoS attack affect mobile and traditional phone lines, or just VoIP systems?
A TDoS attack can target any telephony system, including mobile, traditional PSTN (Public Switched Telephone Network), and VoIP lines. However, VoIP systems are often more susceptible due to their internet-based nature and ease of automation in attack scenarios.