How to Safeguard Your Cisco Expressway from Fraudulent Calls and Spam

In an increasingly connected world, businesses heavily depend on Voice over Internet Protocol (VoIP) technologies to streamline communication, collaborate across global networks, and drive operational efficiency. One of the key enablers of this communication revolution is Cisco’s Expressway, which facilitates secure mobile remote access (MRA) and business-to-business (B2B) communication. However, as with any technological advancement, the rise of VoIP systems introduces new vulnerabilities that can be exploited by malicious entities. Among these, spam and toll fraud calls have become significant concerns for organizations using Cisco Expressway. These fraudulent activities not only threaten the performance of the system but also expose companies to financial risks that could severely impact their bottom line.

What Exactly Are Spam callss and Toll Fraud Attacks?

Spam calls refer to unsolicited, often malicious, phone calls that flood communication networks with automated traffic, typically originating from bots or compromised systems. These automated systems are designed to continuously send Session Initiation Protocol (SIP) INVITE and SIP OPTIONS messages to your network, hoping to bypass the security layers and connect with the Public Switched Telephone Network (PSTN). The result is an excessive number of calls, sometimes reaching several calls per second, leading to an overwhelming volume of traffic in a short time. While these spam calls may not immediately overload the system, they are certainly disruptive and can consume vital network resources, leading to degraded performance across the Expressway deployment.

Toll fraud, on the other hand, refers to the unauthorized use of a company’s communication system to make high-cost calls, often internationre. These fraudulent calls occur when spam calls manage to successfully reach the PSTN, causing the organization to incur unexpectedly high charges. Toll fraud is particularly concerning because it exploits vulnerabilities in the system, allowing attackers to take advantage of international tariffs, which can quickly add up to significant costs. Beyond the immediate financial impact, these fraudulent calls can also waste critical licenses, such as Rich Media Session (RMS) licenses, further complicating the network’s performance and overall security.

How Do Spam Calls Affect Expressway Deployment?

In a Cisco Expressway deployment, the impact of spam calls can be profound, particularly in large-scale networks where traffic volume is already substantial. Spam calls consume system resources such as CPU, memory, and licenses, which could otherwise be utilized by legitimate communications. When a spam call hits the Expressway, it undergoes several internal processes to determine whether the call should be allowed to proceed. This process includes the use of transform rules, search rules, and authorization checks, which can take up to 90 seconds to complete. During this period, resources are consumed unnecessarily, leading to a decline in the performance of the entire system.

The challenge lies not only in the immediate effect on the system’s responsiveness but also in the long-term consequences. If left unchecked, spam call traffic can cause severe resource depletion, making the system more vulnerable to other types of attacks. The result is a less efficient communication environment, which could significantly affect business operations. The potential risks include:

Excessive Call Entries in Call History: Spam calls will frequently appear in call logs, filling up valuable storage space and making it harder for administrators to sift through legitimate traffic. These calls are typically from unknown numbers, many of which mimic the organization’s domain or Expressway IP addresses to evade detection.
License Consumption: In scenarios where spam calls match business-to-business (B2B) search rules, licenses like RMS may be consumed needlessly. These licenses, which are typically reserved for authorized communication, are often a finite resource, and their depletion can lead to limitations in system functionality for legitimate calls.
Increased Monetary Losses: If spam calls manage to evade internal filtering and connect to the PSTN, the company may be left to pay for costly international or premium-rate calls. The financial repercussions can be staggering, especially in scenarios where bot-generated traffic is allowed to run unchecked.
Exposing Security Vulnerabilities: While spam calls may seem like an annoyance at first, they often serve as a precursor to more sinister attacks. Cybercriminals can use these calls to probe the vulnerabilities of the system, searching for weaknesses in the security architecture that they can exploit to launch more sophisticated attacks.

The Threat Landscape: Why Is Expressway More Susceptible to Spam and Toll Fraud Calls?

There are several reasons why Cisco Expressway deployments are increasingly becoming targets for spam and toll fraud attacks. First, the widespread adoption of VoIP and the increasing number of mobile remote access (MRA) deployments make these systems appealing targets for cybercriminals. As businesses embrace the flexibility and scalability of cloud-based communication systems, the volume of external traffic that needs to be processed by Expressway also increases, making the system more susceptible to being overwhelmed.

Additionally, Expressway is designed to facilitate seamless communication between different networks, which, while an advantage, also makes it a potential weak point for unauthorized access. This allows spam callers, often using botnets or compromised devices, to connect to your network and exploit the system’s open access points. Without effective filters or safeguards, these callers can quickly cause significant disruptions.

Moreover, the rise of “disruptive innovation” in the form of advanced automation and AI-driven tools enables attackers to generate massive volumes of traffic with minimal effort. Unlike traditional telephony systems that rely on manual dialing, modern bots can send requests at an overwhelming pace, significantly impairing the normal flow of communication.

Preventing and Mitigating Spam and Toll Fraud in Expressway Deployments

The good news is that organizations can implement several strategies to protect their Cisco Expressway deployments from spam and toll fraud. By taking proactive measures, businesses can safeguard their networks from these disruptive and financially damaging attacks.

Implement Call Authentication Protocols:
One of the most effective ways to protect Expressway deployments from toll fraud is by implementing robust call authentication protocols. Technologies such as Secure Real-Time Transport Protocol (SRTP) and Transport Layer Security (TLS) can help ensure that only legitimate calls are permitted to pass through the system. These protocols encrypt the communication between endpoints, making it harder for attackers to intercept and manipulate calls. Additionally, enforcing strong identity management practices, such as Two-Factor Authentication (2FA), can further reduce the likelihood of unauthorized access.
Use Anti-Spoofing and Filtering Techniques:
A significant portion of spam and toll fraud calls are successful due to spoofing, where attackers falsify caller information to appear as legitimate users. Anti-spoofing measures such as SIP Identity or DKIM (DomainKeys Identified Mail) can help detect and block fraudulent traffic at the signaling layer. Filtering tools such as access control lists (ACLs) and intrusion prevention systems (IPS) can also be used to block traffic from known malicious IPs, preventing bots from reaching the Expressway.
Deploy Real-Time Monitoring and Alerts:
To detect and mitigate spam traffic before it has a chance to impact system performance, real-time monitoring is essential. Network monitoring tools that track call volumes, traffic patterns, and system resources can help identify anomalies and trigger alerts when suspicious activity is detected. By responding to these alerts immediately, network administrators can isolate and mitigate spam calls before they result in toll fraud or system degradation.
Set Up Rate Limiting and Call Throttling:
Implementing rate limiting and call throttling measures can significantly reduce the impact of spam calls on the Expressway deployment. By limiting the number of calls per second or setting maximum thresholds for call duration, businesses can prevent excessive traffic from overwhelming the system. These measures can help keep the system performing optimally, even in high-traffic environments.
Regularly Update and Patch the System:
To ensure that Cisco Expressway is resilient against evolving threats, it’s essential to keep the system updated with the latest patches and security fixes. Regular software updates from Cisco include new security features and bug fixes that help protect against emerging threats.

Building a Robust Defense Against Spam and Toll Fraud

Spam and toll fraud attacks present a serious threat to Cisco Expressway deployments, jeopardizing both system performance and financial integrity. However, with the right combination of proactive security measures, real-time monitoring, and automation, businesses can effectively mitigate these risks and maintain the integrity of their VoIP communications. By adopting a multi-layered security approach that includes call authentication, anti-spoofing, real-time traffic analysis, and regular system updates, organizations can safeguard their Expressway deployments against malicious attacks while ensuring seamless and secure communication for their users.

Identifying the Source of Spam Calls and How They Exploit Expressway

In an era where communication technology is becoming more interconnected and sophisticated, the threat of spam calls has also evolved, growing more devious and insidious with each passing year. These nuisance calls often target individuals and businesses alike, and their origins can be traced back to botnet-based attacks. Understanding the root cause of these attacks and their ability to exploit systems such as Cisco’s Expressway is crucial for crafting a robust defense strategy. With this knowledge, security teams can not only block these intrusions but also enhance the overall protection of their communication infrastructure.

Botnet-Based Attacks: The Origin of Spam Calls

A significant portion of spam calls emanates from botnets, which are essentially vast networks of compromised devices controlled by malicious entities. These devices, often Internet of Things (IoT) gadgets like smart cameras, routers, and even household appliances, are hijacked and used as “zombies” in a coordinated cyber attack. Once in the botnet’s grasp, these devices become part of an army of compromised nodes that work together to exploit weaknesses in networks and systems like Expressway.

Botnets operate by continuously scanning the internet for vulnerabilities. They are programmed to target systems that are improperly secured or exposed to the internet without adequate protective measures in place. One of the most common methods employed by these botnets is to send an onslaught of SIP INVITE and SIP OPTIONS messages to various endpoints, probing for open or unprotected access points. When a botnet identifies a weak system—one with inadequate defenses like weak authentication methods or outdated firmware—it attempts to establish a connection to the Public Switched Telephone Network (PSTN) or a similar service, ultimately causing financial losses and consuming valuable resources.

Even after these attacks are thwarted by basic security measures, such as firewalls or system rejections, the persistence of botnets is notable. These malicious bots do not easily give up; they continuously cycle through different source and destination patterns in search of any potential vulnerability. Their relentless probing is designed to find a weak spot and infiltrate systems that are insufficiently guarded, leading to fraudulent charges or, worse, a complete compromise of the communications infrastructure.

Understanding the Behavior of Spam Call Bots

Unlike traditional denial-of-service (DoS) attacks, which are focused on overwhelming a system with massive traffic, spam call bots operate with a more targeted approach. Their primary objective is not to take a system offline but rather to use it for fraudulent purposes. Spam call bots function by testing different patterns of numbers and sequences, probing the system for any weak points that may allow them to exploit connections for fraudulent calls. These bots are often programmed to attempt different combinations of source IP addresses and destination numbers, mimicking legitimate user calls or internal extensions.

The structured nature of spam call bots means that they can sometimes be very difficult to differentiate from legitimate traffic. They may attempt to use numbers that closely resemble valid phone numbers or extensions within the system, making them particularly effective at bypassing basic detection mechanisms. It is important to recognize that these bots don’t aim to cause catastrophic damage in the traditional sense; their goal is to run up fraudulent calling charges by exploiting open connections.

This behavior necessitates the implementation of proactive security measures to detect and block these bots early in the network flow. If bots are not stopped before they can access vulnerable endpoints, they can quickly lead to significant losses, both in terms of resources and money. To mitigate this risk, it’s essential to implement multiple layers of defense to ensure that these malicious actors do not infiltrate the system unnoticed.

The Importance of Making Your Expressway Invisible

One of the most effective ways to block spam call bots before they can initiate a fraudulent connection is to make your Expressway deployment “invisible” to these bots. By obscuring the presence of your systems on the network, you limit the bots’ ability to even detect that the Expressway exists as a potential target. The more a system appears as an exposed, vulnerable node on the internet, the more likely it is to be targeted by these malicious actors. Conversely, making the Expressway “invisible” reduces the likelihood of botnets finding the system and launching spam calls against it.

A network that is perceived as highly secure and obscured from external probing is far less likely to fall victim to botnet-driven attacks. If the botnet cannot even locate the target system or identify it as a possible attack vector, it will naturally move on to other, more exposed systems that are easier to compromise. This is why securing the perimeter and using advanced network topology design to hide critical communication infrastructure becomes crucial in defending against spam call attacks.

Where Should Spam Calls Be Blocked?

Blocking spam calls is an essential step in safeguarding your communication systems, and it is important to implement this defense at multiple stages in the network flow. The first and most effective line of defense should be at the firewall level. Firewalls play a crucial role in preventing unauthorized access by blocking specific IP addresses, domains, or protocols associated with spam call bots. By setting up firewall rules to deny TCP connections from known malicious sources, you can significantly reduce the chances of spam bots reaching your Expressway.

The firewall acts as a primary barrier, preventing initial connections from entering the system. However, relying solely on firewall protection may not be enough to fully secure the network against spam calls. As such, it is essential to employ additional layers of protection, including more specialized filtering mechanisms at the level of the Expressway itself. These mechanisms, such as Call Processing Language (CPL) rules, allow network administrators to further refine the filtering of inbound traffic based on specific patterns, message types, or call behavior. By doing so, administrators can ensure that even if a bot somehow manages to get through the firewall, it is still prevented from making fraudulent calls.

After filtering out unwanted traffic at the firewall and CPL levels, another layer of security can be implemented using calling search spaces and partitions in the Call Manager. These configurations allow further refinement of the calls that are allowed to enter the system, blocking those originating from suspicious or unrecognized sources.

Advanced Defense Strategies: Detecting and Blocking Spam Calls Effectively

While the firewall, CPL, and call manager are essential first steps in blocking spam calls, a more comprehensive strategy requires a more nuanced approach. Intrusion detection and prevention systems (IDPS) should be employed to continuously monitor network traffic for suspicious patterns. These systems can use machine learning algorithms and advanced statistical models to detect unusual patterns indicative of bot-driven activities. When such activities are detected, the IDPS can alert administrators or automatically take action to block the malicious source.

Additionally, advanced network monitoring tools can be used to identify anomalous behavior in real time. For example, monitoring the frequency and pattern of SIP messages across the network can provide valuable insight into the presence of spam bots. If a large number of requests with similar characteristics are detected, this may indicate the presence of a botnet attempting to exploit the system. Once these threats are identified, they can be swiftly mitigated using automated response mechanisms.

Another critical element in preventing spam call attacks is the proper configuration of anti-spoofing measures. These measures involve verifying that the source of each incoming call is legitimate and that it has not been spoofed by malicious actors. This can be done using mechanisms such as Secure SIP (SIPS) and Transport Layer Security (TLS), which encrypt the communication channel and authenticate the sender’s identity.

Spam calls are a significant nuisance in the modern telecommunications landscape, and their origins in botnet-driven attacks make them a particularly persistent and difficult problem to solve. These bots exploit vulnerabilities in systems like Expressway by relentlessly probing for weak spots and attempting to establish fraudulent connections. While traditional defenses like firewalls and basic security measures can provide some protection, a more comprehensive approach is needed to effectively block these malicious intrusions.

By making your Expressway deployment invisible to these bots, using advanced filtering mechanisms like CPL rules, and implementing deeper monitoring and intrusion detection systems, you can significantly reduce the risk of spam calls. Additionally, employing anti-spoofing technologies and refining your call manager configurations further enhances the overall security posture of your network. With these layered defense strategies in place, your network will be better prepared to ward off spam calls and protect your resources from the financial and operational damage caused by botnet-driven attacks.

Configuring CPL, Automated Detection, and Expressway Internal Firewall for Enhanced Security

As the digital landscape continues to evolve, ensuring robust security in communication networks becomes paramount. One of the critical challenges faced by many organizations is blocking malicious calls such as spam and toll fraud, which can wreak havoc on both operational efficiency and financial stability. Cisco’s Expressway platform provides a comprehensive suite of tools to tackle these issues, including Call Processing Language (CPL), automated detection systems, and an internal firewall. Configuring these features in tandem creates a multifaceted defense mechanism that helps secure your deployment against malicious activity. This guide will walk through the essential steps to configure CPL, automated detection, and Expressway internal firewall settings to mitigate unwanted traffic and safeguard your network.

Configuring CPL for Call Traffic Management

Call Processing Language (CPL) is a versatile feature within Cisco’s Expressway platform that allows network administrators to create tailored rules for managing and controlling incoming and outgoing call traffic. These rules can be configured to identify, block, or reroute calls based on certain criteria, such as patterns in the source or destination address. CPL’s primary role in preventing spam and toll fraud calls is to filter out traffic that matches known patterns of malicious activity, such as calls originating from untrusted or compromised IP addresses.

The first step in configuring CPL is to establish a solid authentication policy that helps the system distinguish between legitimate and malicious traffic. A default authentication policy is usually applied in the Expressway, but you must fine-tune this policy to ensure that spam calls are swiftly rejected.

To get started, configure the authentication policy for the default zone. Setting the policy to “Do not Check Credentials” will immediately reject calls from unverified or suspicious sources, which is crucial in mitigating the impact of spam or toll fraud attempts. This configuration ensures that calls from sources with insufficient or incorrect credentials are filtered out before they even reach the network.

Step-by-Step CPL Configuration Process

Set Authentication Policy: The first critical setting involves adjusting the authentication policy for the default zone. Configure the authentication policy to “Do not Check Credentials,” which ensures that calls originating from unverified or malicious sources are promptly rejected.
Define Source and Destination Patterns: By utilizing regular expressions (regex), you can define specific source and destination patterns that match calls from known spam or toll fraud sources. For example, if you notice that spam calls are originating from numbers with your domain or your Expressway’s IP address, you can set a rule to block those patterns. The regular expressions will allow the Expressway to filter out unwanted traffic before it can overwhelm the system.
Reject Spam Calls: Once the patterns are identified, you can configure the system to reject calls that match the defined patterns. This step is pivotal in ensuring that spam calls are halted in their tracks. By rejecting the malicious traffic early, you reduce the processing load on the system and prevent toll fraud from infiltrating your network.

When properly configured, these settings enable the Expressway platform to automatically reject calls from recognized spam sources, ensuring that your communication channels remain clear of malicious traffic. By focusing on blocking specific patterns of traffic, CPL not only secures your deployment but also minimizes the chances of legitimate traffic being erroneously rejected.

Leveraging Automated Detection for Proactive Security

While CPL offers a powerful method of managing call traffic, automated detection systems provide an additional layer of proactive protection against spam and toll fraud. Automated detection works by monitoring the call logs for patterns of failed authentication attempts—a common sign of spam bots attempting to penetrate the system. These bots often generate multiple failed login attempts in quick succession, signaling malicious intent.

By enabling automated detection, the system will automatically blacklist the offending IP address after a certain number of failed authentication attempts, reducing the burden of manual intervention and preventing further malicious access.

Configuring Automated Detection

To configure automated detection, follow these steps:

Navigate to System Protection Settings: Go to the System > Protection > Automated Detection section of the Expressway interface.
Enable SIP Authentication Failure Detection: Enable the setting for SIP authentication failure detection. This ensures that the system will continuously monitor SIP logs for any failed login attempts.
Define Detection Parameters: You will need to set a detection window (for instance, 3600 seconds, or one hour), within which failed authentication attempts will be counted. Define a trigger level (such as three failed attempts within the detection window), so that once this threshold is crossed, the system will flag the source IP address as potentially malicious.
Set Block Duration: After an IP address is flagged for multiple failed attempts, it is essential to define a block duration for the offending address. A typical duration could be 10,000 seconds, or roughly 12 days, providing ample time to deter malicious actors from trying again.

By automating this process, the Expressway system will block suspicious IPs without requiring constant oversight. The benefit of this approach is that it provides continuous protection without the need for manual intervention, freeing up resources and allowing administrators to focus on other tasks.

Additionally, the automated detection system ensures that malicious activity is addressed in real-time, enhancing the overall security posture of the network and preventing the system from being overwhelmed by spam and toll fraud calls.

Using the Expressway Internal Firewall for the Final Layer of Protection

Even after spam calls and malicious actors are blocked by CPL and automated detection, it is crucial to ensure that any remaining suspicious traffic is blocked at the firewall level. This is where the Expressway internal firewall comes into play. The internal firewall provides an additional layer of protection by controlling the flow of traffic to and from the network.

Once the automated detection has flagged a malicious source, you must ensure that these IP addresses are blocked at the firewall level as well. This is particularly important because malicious actors may attempt to bypass earlier detection systems, and the internal firewall provides a comprehensive barrier to prevent this from happening.

Configuring the Internal Firewall

To configure the internal firewall:

Review Blocked IP Addresses: Go to System > Protection > Firewall Rules > Current Active Rules to review the list of blocked IP addresses. Regularly checking this list ensures that only malicious sources are blocked and no legitimate IP addresses are erroneously included.
Exempt Legitimate IPs: In cases where legitimate IP addresses are mistakenly flagged as suspicious, you can exempt these IPs to prevent them from being blocked again in the future. This feature helps reduce the risk of false positives, ensuring that your network remains accessible to trusted sources while keeping malicious traffic at bay.
Maintain a Robust Firewall Configuration: It’s essential to regularly audit the firewall rules and settings to ensure that they continue to provide effective protection. Regular updates to the firewall configuration can help safeguard against emerging threats and ensure that the system remains resilient in the face of evolving cyberattacks.

By using the internal firewall alongside the CPL and automated detection systems, you create a robust multi-layered defense strategy that helps protect your deployment against a wide range of threats. The firewall acts as a final gatekeeper, ensuring that only trusted and verified traffic is allowed into the network, thus adding an extra layer of security that complements the other systems.

Securing your network against spam and toll fraud calls is a multi-faceted challenge that requires a comprehensive approach. By configuring CPL, automated detection systems, and the Expressway internal firewall, you can create a robust defense against malicious traffic. Each layer of security plays a vital role, from filtering traffic at the call processing level to automating the detection of suspicious activity and blocking malicious IPs at the firewall. Together, these features form a dynamic and responsive security system that helps protect your network from ongoing threats while minimizing the need for manual intervention.

With these advanced configurations in place, organizations can ensure the integrity and reliability of their communication systems, providing a secure foundation for seamless and uninterrupted operations. The key to success lies in continuously monitoring and refining these settings to adapt to new threats and maintain an airtight defense against toll fraud and spam calls.

Best Practices and Final Considerations for Securing Expressway Deployments

Securing your Expressway deployment is critical in a world increasingly targeted by various malicious activities such as spam calls, toll fraud, and performance degradation. With the proliferation of VoIP technology and the growing sophistication of attackers, it’s essential to put in place a comprehensive set of strategies and configurations to mitigate these risks. Following the right best practices ensures that your deployment is resilient to unwanted traffic and stays secure against evolving threats. This article outlines key considerations and strategies for securing your Expressway deployment, focusing on monitoring, auditing, and additional layers of security to safeguard your network.

Monitoring Call Logs and Call History

One of the fundamental steps to proactively identifying threats such as spam calls or toll fraud attempts is regular monitoring of call logs and call history. By staying vigilant and examining the details of each incoming call, network administrators can detect unusual patterns or anomalies indicative of malicious activity. Spam calls often follow recognizable patterns, such as high call volumes originating from unknown numbersor repeated failed authentication attempts. This proactive approach can help identify threats before they cause significant damage or disruption.

Using the Expressway’s built-in tools like the Status > Calls > Call History section, administrators can easily access detailed logs that include information about the origin of each call, authentication attempts, and call duration. Regularly reviewing these logs allows network engineers to spot any suspicious activity, such as a sudden spike in calls from non-registered IPs or unusual geographic locations.

For instance, a significant increase in calls from international regions or IP addresses that don’t match any known business relationships might signal the early stages of toll fraud. Conversely, numerous failed authentication attempts followed by a successful login from a previously unknown IP address could indicate a bot attack or other forms of cyber intrusion. The more often these logs are reviewed, the better equipped administrators are to respond promptly and appropriately.

Moreover, integrating automated alerts into your monitoring system can help streamline this process. Anomalies such as unusually high volumes of calls, failed logins, or unrecognized sources can trigger immediate alerts, allowing network engineers to take corrective action before the attack escalates.

Regular Audits and Updates

A key aspect of ensuring that your Expressway deployment remains secure is regular audits and updates. Security threats evolve rapidly, and what might be an effective security measure today could be inadequate tomorrow. To stay ahead of the curve, you should regularly audit your deployment’s configuration, firewall settings, and various security parameters. Regular updates to both the system and security profiles ensure that vulnerabilities are patched and defenses are always up-to-date.

One of the primary areas to audit is the CPL (Call Processing Language) rules, which are pivotal in blocking unwanted or malicious traffic. These rules are critical for ensuring that calls from suspicious sources are blocked before they can enter your network. However, as new spam patterns and toll fraud techniques evolve, it’s necessary to periodically revisit and adjust the CPL rules to ensure they continue to effectively filter out threats.

In addition, auditing your firewall settings is essential to ensure that legitimate traffic is not mistakenly blocked while preventing unauthorized access. Over time, firewall configurations may need to be modified as new IP addresses are introduced or as network traffic patterns change. By continuously assessing and refining your firewall settings, you minimize the risk of security breaches.

Furthermore, reviewing blocked IP addresses is a good practice during audits. It’s vital to verify that legitimate services are not accidentally affected by overly aggressive blocking tactics. False positives—where legitimate calls or traffic are mistakenly classified as threats—can hinder communication and degrade the user experience. A thorough audit helps to fine-tune these settings and prevent such issues from arising.

Additional Layer of Security: Calling Search Spaces and Partitions

While the use of CPL rules and firewalls provides a robust first layer of defense, they are not foolproof. For added protection, integrating Calling Search Spaces (CSS) and Partitions within your Call Manager adds a second layer of security to your Expressway deployment. This layered approach is an effective strategy for isolating and controlling different traffic types, preventing unauthorized calls from reaching sensitive areas of the network.

Calling Search Spaces and Partitions allow you to logically group and segregate calls, so only those calls that meet specific criteria are allowed to access certain resources. For example, by using Calling Search Spaces, you can isolate calls from external sources or unknown numbers from internal resources, thereby reducing the chances of toll fraud or unauthorized access. This ensures that only the appropriate calls reach sensitive areas of your network, further minimizing the attack surface.

By segregating traffic, you ensure that even if malicious actors manage to bypass the initial layer of defense—such as a misconfigured CPL rule—they still cannot access critical resources. The integrity of your internal communications remains intact, and unauthorized traffic can be blocked or redirected as needed.

Additionally, when configuring these partitions, you can further optimize your network by ensuring that certain traffic types (such as video conferencing calls or emergency services) are prioritized or receive different treatment from standard voice traffic. This can also help in managing network performance, ensuring that mission-critical services receive the necessary bandwidth and attention during periods of high traffic.

Automating Alerts and Responses to Suspicious Activity

Automation can play a crucial role in quickly identifying and mitigating threats to your Expressway deployment. Automated responses to suspicious activity can be particularly useful in preventing spam calls or toll fraud from escalating into more significant incidents. For instance, integrating real-time alerts and automated block actions based on specific traffic patterns or authentication failures can drastically reduce the reaction time of network administrators.

For example, if the system detects an unusual spike in call volume from unrecognized IP addresses, it could trigger an automatic response to temporarily block these addresses from accessing the system. Similarly, if multiple failed authentication attempts occur within a short timeframe, the system could automatically trigger a temporary lockout, preventing further intrusion attempts.

This level of automation not only enhances the security of the system but also ensures that your team doesn’t have to spend valuable time manually responding to each alert. Automated systems can act faster than human intervention, reducing the window of opportunity for malicious actors to exploit vulnerabilities.

Furthermore, automated systems can be configured to notify administrators or security teams through SMS or email alerts, allowing them to respond immediately if manual intervention is needed. These automated actions and alerts can be customized to suit the specific needs and thresholds of your network, ensuring that the response is proportional to the severity of the threat.

Conclusion

Securing an Expressway deployment from spam calls and toll fraud is not a one-time task; it is an ongoing process that involves regular monitoring, audits, and the application of best practices. By actively reviewing call logs and history, performing consistent audits, and regularly updating security protocols, network administrators can stay ahead of evolving threats. Additionally, implementing advanced security measures like Calling Search Spaces and Partitions creates an extra layer of protection to safeguard the network’s most sensitive resources.

The integration of automated alerting and response systems can further enhance security, allowing your network to react to suspicious activity in real time, minimizing potential damage. Adopting a layered, proactive approach to security ensures that your Expressway deployment remains robust, resilient, and secure in the face of increasingly sophisticated threats.

By adhering to these best practices and continuously refining your security posture, you can not only defend against toll fraud and spam calls but also optimize your network’s performance, ensuring a secure and smooth communication experience for all users. This dynamic approach to network security is essential in today’s fast-paced, ever-changing environment.