Security Operations Centers (SOCs) have long relied on geographic blocking as a straightforward defense against attacks such as distributed denial-of-service (DDoS), credential stuffing, vulnerability scanning, and unwanted web scrapers. The logic seemed sound: block traffic from certain countries or regions where attacks commonly originate, and you could significantly reduce malicious activity targeting your infrastructure. Over time, this tactic became a DDoS countermeasure of last resort for small countries: by blocking foreign traffic, they could mitigate large attacks but keep domestic services operational.
However, recent security incidents and evolving attack methodologies reveal a troubling reality. Geo-blocking is becoming increasingly ineffective as attackers adapt their tactics, exploit compromised devices worldwide, and launch attacks from inside their target geography as an evasion technique. The emergence of massive botnets and proxy networks built from hijacked routers, open proxies, and endpoints that allow tunneling without access controls demonstrates that this once-reliable defense strategy requires reassessment and augmentation with additional controls.
The cybersecurity landscape has shifted dramatically, with several high-profile announcements highlighting vulnerabilities that render geo-blocking less effective than ever before. Understanding these changes is crucial for organizations that depend on geographic filtering as part of their DDoS mitigation strategy.
Geo-Blocking is Still Widely Used in DDoS Defense
Many organizations rely on geo-blocking as part of their security strategy since it is relatively easy to implement. Each country or region is a group of network blocks, which makes geo-blocking a straightforward way to deny access to traffic originating from specific locations. However, this approach is not without its challenges. Cybercriminals can use proxy servers, VPNs, or botnets with devices distributed across multiple regions to bypass these restrictions, rendering geo-blocking less effective.
Commercial DDoS Mitigation Providers
Major DDoS mitigation providers, such as DigiCert and others, use a variety of advanced techniques to safeguard networks from malicious attacks. Among these techniques, geo-blocking plays a crucial role as one component of their multi-layered defense strategies. By integrating geographic filtering into their systems, these providers can block or restrict traffic from specific regions that are often associated with high levels of malicious activity, such as botnets or known sources of cybercrime.
Geo-blocking is typically combined with other security measures to create a more robust and comprehensive approach to DDoS protection. These measures often include rate limiting, which controls the flow of incoming requests to prevent overwhelming servers; behavioral analysis, which monitors traffic patterns to identify suspicious activity; and signature-based detection, which matches known attack signatures to quickly flag and block threats. Together, these methods ensure that the system is equipped to detect, respond to, and mitigate a wide range of attack vectors.
One of the key advantages of geo-blocking is its ability to quickly reduce the attack surface, allowing providers to filter out large volumes of potentially harmful traffic before it even reaches the network. By targeting traffic from regions with a history of malicious activity, providers can not only enhance security but also allocate their resources more efficiently. This ensures that more attention can be devoted to analyzing and mitigating threats from higher-risk or more sophisticated sources, improving the overall effectiveness of the defense system. As cyber threats continue to evolve, the use of geo-blocking and other layered strategies remains essential in maintaining network security and reliability.
WAF and CDN Integration
Web application firewalls (WAFs) and content delivery networks (CDNs) often come equipped with geo-blocking capabilities as part of their standard feature sets. These powerful tools allow administrators to create custom rules that block traffic from specific countries or regions, tailoring access to the needs of their platforms. For instance, if a business primarily serves users in North America, geo-blocking can restrict traffic from regions where no legitimate users are based, reducing unnecessary load on servers.
One of the key advantages of geo-blocking is its ability to enhance security. By preventing access from high-risk locations that are often associated with malicious activity or cyberattacks, organizations can significantly reduce the likelihood of threats such as DDoS attacks, data breaches, or other forms of exploitation. This creates a safer and more secure environment for legitimate users, ensuring their data and interactions remain protected.
In addition to security benefits, geo-blocking also plays a valuable role in optimizing the performance of web applications and content delivery. By filtering out traffic from irrelevant or harmful sources, CDNs and servers can focus their resources on delivering content efficiently to regions with genuine users. This results in faster load times, reduced latency, and an overall better user experience for those accessing the platform from approved locations.
By combining security and performance optimization, geo-blocking has become an essential feature for many modern web platforms. Whether protecting against cyber threats or ensuring smooth content delivery, these capabilities illustrate the importance of leveraging technology to create a safer and more reliable digital experience.
Small Nations Use Geo-Blocking as a Fallback DDoS Defense
Some smaller countries with limited internet infrastructure continue to rely on broad geo-blocking as an emergency response during large-scale cyberattacks. In the face of overwhelming DDoS attacks, these nations may temporarily block access to entire countries, regions, or even all foreign network traffic to protect their internal networks. This drastic approach can provide immediate relief by cutting off malicious traffic and preventing further strain on their systems. However, while effective in the short term, this strategy comes with significant downsides. By blocking large swaths of international Internet traffic, these measures unintentionally disrupt legitimate connections, affecting businesses, organizations, and individuals who depend on seamless global communication. The collateral damage can have far-reaching implications, from hindering international trade to limiting global collaboration.
During geo-blocking of foreign network traffic, many Internet Service Providers (ISPs) within these countries implement internal measures to mitigate the impact on domestic users. By relying on internal peering and Border Gateway Protocol (BGP) communities, they ensure uninterrupted access to domestic websites and critical services. This allows essential platforms, such as government portals, healthcare systems, and banking services, to remain operational and accessible to citizens. In this way, people can stay connected to the services they depend on daily, even while the country takes drastic measures to fend off external threats. Although this approach has its drawbacks, it highlights the balancing act smaller nations face in safeguarding their digital infrastructure while attempting to maintain connectivity for their citizens.
Recent Security Events Signal Growing Threats
The past year has brought a series of concerning vulnerabilities, incidents, and warnings that collectively illustrate why geo-blocking is losing effectiveness against modern DDoS campaigns.
FBI Issues Critical Router Warning
In May 2025, the FBI released a flash notice identifying 13 end-of-life Linksys router models vulnerable to remote exploitation. These devices, including popular models like the E1200, E2500, and WRT320N, lack ongoing security updates and contain known vulnerabilities that allow attackers to install malware and establish persistent access.
The compromised routers become part of proxy networks, with cybercriminals selling access to other threat actors who use these devices to mask their true locations. This development directly undermines geo-blocking effectiveness, as attacks can now appear to originate from legitimate residential IP addresses across multiple countries.
CISA Highlights TP-Link Vulnerabilities
The Cybersecurity and Infrastructure Security Agency added CVE-2023-33538, affecting certain TP-Link wireless routers, to its Known Exploited Vulnerabilities catalog. This command injection vulnerability allows attackers to execute arbitrary system commands on affected devices, creating another avenue for establishing distributed attack infrastructure.
With CISA requiring federal agencies to address this vulnerability by July 2025, the urgency of the threat becomes clear. However, many of the affected router models have reached end-of-life status, meaning they will remain vulnerable indefinitely in home and small business networks.
GreyNoise Uncovers ASUS Router Campaign
GreyNoise researchers discovered an ongoing exploitation campaign affecting thousands of ASUS routers worldwide. The attackers use a sophisticated approach, chaining authentication bypasses with the exploitation of CVE-2023-39780 to gain persistent access to devices.
What makes this campaign particularly concerning for geo-blocking strategies is its stealth and persistence. The attackers enable SSH access on custom ports, insert their own authentication keys, and store configurations in non-volatile memory. This ensures their access survives both reboots and firmware updates, creating a stable foundation for long-term botnet operations.
Academic Research Reveals Tunnel Networks
Researchers at KU Leuven published findings about “Tunnelpocalypse” – the abuse of tunneling protocols to create covert communication channels. This research demonstrates how attackers can route traffic through legitimate tunneling services, making it appear as though attacks originate from trusted sources rather than blocked geographic regions. This technique will undoubtedly be used in the future to trigger attacks or to tunnel attacks.
DDoS Attack on Polish TV During the Euros Tournament
During the Euros football competition, Polish TV experienced a significant Distributed Denial of Service (DDoS) attack that disrupted the online stream. Notably, this attack had all the hallmarks of a botnet operating domestically, with malicious traffic originating from within the country. By leveraging local infected devices, the attackers were able to bypass traditional geographic traffic filters. This incident highlights the growing threat of localized botnets being used to target national infrastructure, making it increasingly difficult to detect and mitigate such attacks in real-time.
How Attackers Evade Geographic Restrictions
Modern botnet operators have developed sophisticated techniques to circumvent geo-blocking defenses, making these protections significantly less reliable than in previous years.
Promiscuous Proxy Networks
Attackers increasingly rely on compromised devices that function as open proxies, allowing traffic to be relayed through multiple geographic locations before reaching its target. These “promiscuous proxies” can be created from any internet-connected device with sufficient processing power and network access.
The FBI’s recent seizure of the 5Socks and Anyproxy services illustrates the scale of these operations. These platforms sold access to thousands of compromised devices worldwide, allowing customers to route traffic through residential IP addresses in virtually any country.
Compromised Router Infrastructure
The exploitation campaigns targeting Linksys, TP-Link, and ASUS routers demonstrate how attackers build distributed infrastructure from compromised home networking equipment. These devices are particularly valuable because they:
- Maintain persistent internet connections
- Process traffic for multiple users, providing natural cover
- Appear as legitimate residential IP addresses in geolocation databases
- Often remain unpatched for extended periods
When attacks route through compromised routers in trusted countries, geo-blocking becomes not just ineffective but potentially counterproductive, as blocking these addresses could impact legitimate users.
Compromised Server Networks
Beyond home routers, attackers target servers in data centers, cloud platforms, and hosting providers to create geographically distributed attack infrastructure. Compromised servers offer several advantages:
- Higher bandwidth capabilities for larger attacks
- Professional network connections with better uptime
- IP addresses associated with legitimate business entities
- Access to additional server resources for launching coordinated campaigns
Networks Allowing IP Spoofing
The exploitation of networks that fail to implement Best Current Practice 38 (BCP38) is a key enabler of malicious activities like IP spoofing. By forging source IP addresses on packets, attackers can disguise their true location, making it difficult to trace their origin by sending packets that seem to come from any country or region. Networks that do not adhere to BCP38 allow spoofed packets to pass through, significantly amplifying the scale of DDoS attacks and other malicious traffic. The absence of strict ingress filtering on these networks creates vulnerabilities that attackers readily exploit, enabling reflection and amplification attacks that rely on falsified source addresses. Implementing BCP38 is a simple yet crucial step to mitigate these risks, ensuring only legitimate traffic is allowed and reducing the overall impact of IP spoofing across the internet.
Abusing Tunneling Protocols (“Tunnelpocalypse”)
Attackers have increasingly turned to exploiting tunneling protocols as part of their strategies to obscure activities and amplify their operations. Using a technique often referred to collectively as “Tunnelpocalypse,” these malicious actors repurpose legitimate tunneling protocols such as IP-in-IP, GRE, 4in6, and 6in4 tunneling to bypass detection and security measures. By tunneling malicious traffic through trusted networks, attackers can disguise the origin of their activities, hide command and control (C2) communications, and evade network defenses. This abuse not only complicates attribution but also allows attackers to leverage encryption within tunnels, making it harder for defenders to monitor or intercept malicious traffic. The growing use of tunneling protocols in these scenarios highlights the need for enhanced monitoring and defensive strategies to detect and mitigate such threats.
DigiCert UltraDDoS Protect Uses a Layered Approach
DigiCert’s UltraDDoS Protect service demonstrates how modern DDoS mitigation platforms go beyond traditional geographic filtering by integrating advanced technologies such as geo-blocking alongside other sophisticated defensive techniques. Instead of solely relying on geographic filtering, this comprehensive approach ensures stronger and more effective protection against distributed denial-of-service (DDoS) attacks, providing businesses with the ability to maintain uptime and safeguard critical infrastructure in the face of increasingly complex threats. By combining multiple layers of security, DigiCert’s UltraDDoS Protect sets a new standard for robust and reliable DDoS mitigation strategies.
The platform combines several complementary approaches:
Behavioral Analysis: Traffic patterns are continuously monitored and analyzed in real-time to detect any unusual or anomalous behavior that could signal the presence of a potential cyberattack. This analysis is thorough and comprehensive, focusing on identifying irregular patterns or activities, regardless of their geographic origin. By closely examining these traffic behaviors, the system ensures early detection and mitigation of threats, providing robust protection against malicious activities, no matter where they may originate.
Rate Limiting: Connection and request rates are carefully monitored and controlled on a per-source basis, ensuring that no single source can overwhelm or disrupt target resources. This approach helps maintain system stability, prevents potential abuse or overloading, and ensures fair and efficient resource allocation for all users.
Signature Detection: Known attack patterns and malicious payloads are carefully identified and blocked based on their specific content and behavior, rather than relying solely on their source location. This approach ensures a more robust defense by focusing on the characteristics of the threat itself, preventing harmful actions regardless of where they originate.
Custom Filter Lists: Customers can define tailored filter lists to block traffic that falls outside their normal data flows. By specifying allowed IP ranges, protocols, or other criteria, these filters help ensure that only legitimate and expected traffic reaches their systems, further enhancing protection against unwanted or malicious activity.
Threat Intelligence Feeds: Threat intelligence feeds, such as IP reputation lists, are invaluable tools for strengthening security strategies. These feeds provide real-time data and insights into known malicious IP addresses, domains, and other indicators of compromise. By integrating this information, organizations can proactively block or monitor suspicious traffic before it impacts their systems. Threat intelligence feeds are continually updated, ensuring that defenses stay current with evolving threats. When combined with other security measures, such as custom filter lists, they add another critical layer of protection by leveraging global intelligence to identify and mitigate risks efficiently.
Geographic Filtering: IP-based location filtering is applied selectively to enhance security, focusing on regions that consistently show unusually high volumes of cyberattacks or malicious activity. This approach helps minimize risks while maintaining carefully crafted exceptions to allow legitimate business traffic to flow uninterrupted. By striking this balance, organizations can protect their networks without disrupting normal operations or access for valid users.
Skilled Operators and Adaptive Mitigation: Experienced operators play a critical role in fine-tuning defenses and adapting mitigation strategies to the specifics of each attack. Their expertise allows for the dynamic adjustment of parameters and security protocols based on real-time analysis of threat patterns. By leveraging their in-depth understanding of attack vectors and behaviors, these skilled professionals can quickly identify and address gaps, ensuring an optimal balance between security and accessibility. This proactive approach enhances an organization’s ability to respond effectively to the constantly evolving threat landscape.
This multi-layered approach acknowledges that relying on geo-blocking alone is not sufficient to provide adequate protection against modern DDoS campaigns. These attacks have become increasingly sophisticated, often leveraging networks of compromised devices, known as botnets, that operate across multiple countries. By incorporating additional measures alongside geo-blocking, organizations can better defend against these highly distributed and complex threats.
Prepare Today for Future Threats
The cybersecurity landscape continues to evolve, with new attack vectors and evasion techniques emerging regularly. Organizations must remain adaptable and forward-thinking in their approach to DDoS defense.
The widespread compromise of home networking equipment represents a fundamental shift in how attacks are launched and distributed. As more devices become internet-connected and attackers develop more sophisticated exploitation techniques, the geographic distribution of attack sources will likely become even more diverse and harder to predict.
Success in defending against future DDoS campaigns will depend on organizations’ ability to implement comprehensive, adaptive defense strategies that can respond to evolving threats regardless of their apparent geographic origin. While geo-blocking may retain some value as part of a broader security strategy, it can no longer serve as the primary line of defense against distributed attacks.
By understanding these evolving threats and implementing appropriate countermeasures, organizations can better protect their infrastructure and users against the next generation of DDoS campaigns.
Protecting your organization from DDoS attacks requires a proactive and tailored approach. Our team of experts is here to help you assess your needs and implement a comprehensive mitigation strategy that suits your unique requirements. Don’t wait until an attack disrupts your operations—reach out to us today and ensure your business stays online.
