How to configure FlowSpec on Juniper Routers
Overview: BGP FlowSpec (Border Gateway Protocol Flow Specification) is an extension of the BGP protocol used to define traffic filtering rules on routers; in simpler terms, it can generate firewall rules on routers based on a BGP announcement. Unlike conventional BGP, which routes based on IPv4/IPv6 and prefix information, BGP FlowSpec allows network administrators to specify more granular criteria for packet forwarding, including Layer 4 information (TCP/UDP ports) and even packet patterns. To learn more about BGP Flowspec, check out our article explaining what BGP Flowspec is by clicking this link. Operation: BGP FlowSpec works by adding new types of attributes to BGP, allowing network administrators to specify detailed filtering rules. These rules can include criteria such as: The following actions can be taken with BGP FlowSpec: When these rules are propagated through the BGP network, routers can use this information to filter or manipulate traffic according to the defined policies. Operation – More Details: In the context of BGP FlowSpec, the actions are specified as part of the filter rules. Each filter rule contains three main parts: Actions in BGP FlowSpec are coded using BGP communities. Each action is mapped to a specific BGP community: When you create a BGP FlowSpec rule, you specify the matching fields, the desired action and, optionally, protocol fields. This rule is then encoded as a BGP community and included in a BGP update message that is sent to neighboring routers. The routers that receive this rule apply the specified actions to the packets that match the matching criteria. Please note that the specific BGP communities for each action may vary depending on the BGP FlowSpec implementation on your network equipment. I recommend consulting your equipment’s documentation for detailed information on the BGP communities associated with each action in BGP FlowSpec. Use Cases: 1. **DDoS attack mitigation: BGP FlowSpec can be used to block or redirect malicious traffic during distributed denial of service (DDoS) attacks. Precise rules can be applied to filter out unwanted traffic and keep services online. 2. **QoS (Quality of Service) policies: Network administrators can use BGP FlowSpec to guarantee quality of service by prioritizing certain types of traffic based on specific ports or protocols. 3. **Implementing Security Policies**: BGP FlowSpec can be used to implement granular security policies, blocking traffic associated with malware or suspicious activity. Configuration examples: The BGP FlowSpec configuration may vary depending on the network equipment used. This example explores how to design a DDoS mitigation solution in which a service provider allows its customers to advertise BGP FlowSpec routes to it. It also discusses some of the best practices that should be considered before implementing this type of solution and, finally, some of the Junos commands available to help you check that your Flow-spec solution is working correctly. Topology scenario for the example: Let’s start by taking a look at how our solution will be configured: As we can see in the topology above, there is “BORDA,” a Juniper device that serves as the network’s BGP router, and “Made4Flow,” the software that will analyze the flows, dynamically generate BGP FlowSpec rules, and advertise them via BGP to the BGP router called “BORDA.” In this scenario, the example attack is a DNS amplification attack. This means that the network is receiving a large volume of UDP port 53 packets that it doesn’t actually need for the ISP to function normally. The attack fills the circuit between the ISP and the operators and effectively renders the network inoperable. When the attacker decides to launch the attack, the ISP can use Made4Flow to generate a BGP FlowSpec route specifically for UDP port 53 packets and announce it to the BGP EDGE router, which can then convert that route into a firewall filter on its interfaces that communicate with the carriers. And then this blocks the DNS amplification packets at the edge of the ISP’s network and also at the carrier (if the carrier supports FlowSpec sessions), but allows legitimate traffic to continue arriving. First, let’s look at the BGP FlowSpec session settings on the BORDA BGP router with Made4Flow, assuming that the router is already configured for normal BGP unicast routing (Normal BGP session for announcing Blackhole or Mitigation/Scrubbing Center routes). To configure a BGP FlowSpec session on Juniper devices, we use the following commands: Good practices: There are best practices for protecting this solution. Both the BGP FlowSpec routes and the resulting firewall filters they create are finite resources in the router. Therefore, the BGP EDGE router can filter incoming routes to ensure that it does not receive more routes than expected or incorrect routes. Prefix Limit: So the first thing to do is to set a prefix limit for BGP FlowSpec routes. You could simply set a single prefix limit for the inet unicast and inet flowroutes; however, this example will set a separate limit for the inet flowroutes. To ensure that Made4Flow can send only ten BGP Flowspec routes at a time, let’s set the prefix limit to 10 (this configuration should be adjusted according to each scenario): Route Policy : The next thing to do is to apply an inbound route policy. This policy will limit the router to receiving prefixes that are from the ISP itself with prefixes /24 to /32, which are those announced by Made4Flow. Let’s also add a Community 64496:86 so that it can identify the routes as BGP FlowSpec routes. For all other routes, you can simply filter them based on the client’s route assignment: 1. Create the policy definition: 2. Apply the policy as an import policy in the BGP session with Made4Flow: Maximum prefixes: The last thing to do is to set a maximum number of BGP FlowSpec prefixes that can be installed in the routing table. This example sets a maximum of 10,000 routes, but let’s also configure the router to notify the administrator via a syslog message when a 90% threshold is reached. This configuration must be applied to all routers in the ISP’s network
What is FlowSpec? How to use FlowSpec to mitigate DDoS attacks?
Essentially, Flowspec is an extension of the BGP protocol that allows routers to apply rules—such as dynamic ACLs or dynamic firewall rules—to specific types of traffic. These rules can be based on a variety of criteria, including source, destination, protocol, port, and so on.
The Importance of Made4Flow’s New AntiDDoS Decoders
In recent months, our technical team has seen an alarming increase in DDoS attacks of the Carpet bombing type, characterized by intense traffic spikes generally directed at all IP addresses belonging to the ASN. These attacks have negatively impacted network connectivity, presenting an additional challenge in evading detection by many conventional DDoS security systems. Unlike traditional attacks, which focus on a single IP address, these latest attacks show greater sophistication. They send smaller volumes of traffic distributed among several IP addresses, making identifying patterns and distinguishing between legitimate traffic and DDoS attacks a much more complex task. In response to these evolving cybercriminal tactics, the AntiDDoS development team at Made4Flow has taken proactive measures. We recently implemented a series of new decoders to strengthen our detection system. This improvement aims to enhance the accuracy and reliability of our anomaly detection and analysis tool, significantly improving our ability to identify and neutralize more sophisticated DDoS attacks, by taking automated actions that were previously configured in our tool—such as BGP prefix announcements for mitigation or Clean Pipe (scrubbing center) links — in addition to generating reports on the identified attack. In this article, we’ll explore the details of these new Decoders, developed on the basis of extensive Made4Flow analysis and packet captures. These implementations aim to improve the resilience of AntiDDoS, providing a more efficient defense against the complexities of contemporary DDoS attacks. New Decoders from AntiDDoS Made4Flow: • Port 0: Enables the identification of DDoS attacks that use port ZERO in the UDP protocol within an IP packet, whether as the source or destination, since this tactic is frequently used in DDoS amplification attacks.• DNS: A common feature of DDoS attacks is the receipt of packets from DNS servers or hosts responding to DNS requests. These attacks are known as DNS amplification and involve zombie machines (infected machines), servers or assets responding to DNS requests, and the target.• NTP: Another widely used tactic involves attacks using NTP servers. Like DNS-based attacks, these are known as NTP Amplification, exploiting servers or hosts that respond to NTP requests to direct the attack toward its target. Although it is common for devices connected to the network to make NTP queries to keep the date and time up to date, it is possible to improve the detection of DDoS attacks by setting a standard traffic threshold using a decoder.• SSDP: The Simple Service Discovery Protocol (SSDP) can be exploited to send large volumes of packets to the target, abusing device discovery services to amplify the attack and disrupt the target’s connectivity.• IP Fragmentation: Packet fragmentation can occur when a device is unable to send all the necessary information in a single packet. The main issue is that firewall blocks may not be as effective, and large DNS response packets may use fragmented packets. An excess of these packets can impact the network and consume excessive resources from network devices; with this decoder, we can set a threshold and make detection more accurate.• TCP SYN: This decoder plays a key role in detecting attacks known as SYN floods, which involve consuming the resources of servers or device services, rendering them unavailable for use. By setting the correct threshold, we can implement effective preventive measures, preventing this type of attack from occurring and taking actions that result in immediate mitigation.• LDAP: The LDAP decoder plays an important role in identifying DDoS attacks that exploit servers with active LDAP to perform reflections, thereby amplifying malicious traffic.• Chargen: Although it is an older protocol, it is used in some line printers and can be exploited by attackers. Setting a limit for this type of traffic is also important.• TCP and UDP High Ports: In addition to the protocols mentioned above, we have observed in several DDoS attack reports the use of high ports—above port 1024—with the TCP and UDP transport protocols. Therefore, it is important to set limits for these two protocols, making the detection of attacks that use high ports more effective. The addition of new decoders makes DDoS attack detection more efficient by supporting a variety of protocols, protecting against different types of DDoS attacks, minimizing false positives, and enabling more accurate identification of real threats. Acessar a demo do Made4FlowSuporte (WhatsApp)
Internet service providers face a new wave of DDoS attacks
A lack of care in maintaining equipment, services, and IP address block configurations has put ISPs at imminent risk of distributed denial-of-service attacks Internet service providers (ISPs) are at imminent risk of large-scale distributed denial-of-service (DDoS) attacks, largely due to a lack of care in managing equipment, services, and the configuration of IP address blocks. Last year, several Brazilian ISPs faced difficult times as they dealt with DDoS attacks on their infrastructure, a situation that led to numerous posts on social media, as well as coverage in newspapers and on TV shows. Recently, in late February, a new wave of attacks once again hit several ISPs, with numerous reports involving providers in Rio de Janeiro, some of whom have even spoken out publicly, informing customers that they are facing serious problems in providing services due to these attacks. The victim is not necessarily the target Despite the disruptions they cause to internet service operations, DDoS attacks targeting ISPs—contrary to popular belief—do not necessarily target the ISPs themselves. In most cases, the goal of hacker groups is to use these companies’ infrastructure to attack their actual targets, which are usually large multinational corporations. Equipment with inadequate or incorrect configurations, along with human error, are typically factors that facilitate the exploitation and “recruitment” of this infrastructure into the criminal underworld. During large-scale DDoS attacks, victims are typically hit with a high volume of requests originating from thousands—and sometimes tens of thousands—of different sources, usually spread across the globe. Mitigation measures and strategies that rely on human effort to identify the sources of attacks become ineffective in the face of hackers’ enormous firepower, since these attacks originate from thousands of different malicious sources that suddenly flood the victim’s infrastructure. That is why it is best to rely on an Anti-DDoS system. DDoS attacks spread across 181 countries On the 12th of last month, about two weeks before the new wave of DDoS attacks was made public, Hacknet, an artificial neural network designed to identify hacking activity worldwide, identified and mapped a large network of more than 40,000 servers, spread across 181 countries, that were being used to launch DDoS attacks. The news was posted on the website and social media accounts of NetSensor, the company that maintains this neural network, along with a link to download the list of IP addresses being used in the attacks, so that security professionals could take preventive measures to protect themselves. NetSensor reviewed the list of devices that were being exploited, enriched it with additional data, and sent private notifications to the email addresses registered as the contact information for each IP address block. In Brazil, more than 1,000 companies were involved, resulting in more than 1,600 contact emails, in which NetSensor issued the alert, provided information about the device, and made itself available to answer any further questions. The results of the notifications were a negative surprise, with things like: The saddest response came from the person in charge of a provider’s server, who simply wrote: “Please remove my email from the list.” Few companies take this seriously There were also some companies that responded positively to the alert. Some forwarded the case to the person in charge of the device using that IP address; others requested more information about the case; and still others thanked us for the alert and said they would review the case and take the necessary measures. Unfortunately, the percentage of companies that took this more serious and professional approach was around 0.5%. Given this scenario, companies in general need to keep in mind that cybercrime has become much more sophisticated in recent years; it has become highly organized, structured, intelligent, and profitable. Therefore, to be able to confront and defend against these cybercriminals, we must develop techniques and knowledge and make intelligent use of resources that match the level of our attackers. In other words, we must seek out new approaches and technologies capable of helping us defend against emerging threats—threats that we are currently unable to address effectively. Furthermore, the neglect, incompetence, and negligence we see in relation to networks, equipment, and services can no longer be tolerated. Only then will we have a chance of success in confronting the threats that surround us, coming from the dark side of the internet. Source: https://www.cisoadvisor.com.br/provedores-de-internet-enfrentam-nova-onda-de-ataques-ddos/ How to Protect Your Internet Service Provider from DDoS Attacks Just as there are tools used by attackers, we also have tools and methods to protect the service provider. What we need to do is mitigate the attack, which involves protecting the target from DDoS attacks. Made4it has the right tool for you: Made4Flow!With Made4Flow, you can detect attacks and take action to protect your provider. Learn about the benefits of anti-DDoS for internet service providers:
