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This section will cover threat vectors faced by services facing external/internal clients. Potential mitigation options to consider while deploying them. This will touch upon perimeter security, DDoS protection, Network demarcation and operational practices.

Security Threat

Security is one of the major considerations in any infrastructure. There are various security threats, which could amount to data theft, loss of service, fraudulent activity, etc. An attacker can use techniques like phishing, spamming, malware, Dos/DDoS, exploiting vulnerabilities, man-in-the-middle attack, and many more. In this section, we will cover some of these threats and possible mitigation. As there are numerous means to attack and secure the infrastructure, we will only focus on some of the most common ones.

Phishing is mostly done via email (and other mass communication methods), where an attacker provides links to fake websites/URLs. Upon accessing that, victim's sensitive information like login credentials or personal data is collected and can be misused.

Spamming is also similar to phishing, but the attacker doesn't collect data from users but tries to spam a particular website and probably overwhelm them (to cause slowness) and well use that opportunity to, compromise the security of the attacked website.

Malware is like a trojan horse, where an attacker manages to install a piece of code on the secured systems in the infrastructure. Using this, the hacker can collect sensitive data and as well infect the critical services of the target company.

Exploiting vulnerabilities is another method an attacker can gain access to the systems. These could be bugs or misconfiguration in web servers, internet-facing routers/switches/firewalls, etc.

DoS/DDoS is one of the common attacks seen on internet-based services/solutions, especially those businesses based on eyeball traffic. Here the attacker tries to overwhelm the resources of the victim by generating spurious traffic to the external-facing services. By this, primarily the services turn slow or non-responsive, during this time, the attacker could try to hack into the network, if some of the security mechanism fails to filter through the attack traffic due to overload.

Securing the infrastructure

The first and foremost aspect for any infrastructure administration is to identify the various security threats that could affect the business running over this infrastructure. Once different threats are known, the security defence mechanism has to be designed and implemented. Some of the common means to securing the infrastructure are

Perimeter security

This is the first line of defence in any infrastructure, where unwanted/unexpected traffic flows into the infrastructure are filtered/blocked. These could be filters in the edge routers, that allow expected services (like port 443 traffic for web service running on HTTPS), or this filter can be set up to block unwanted traffic, like blocking UDP ports, if the services are not dependent on UDP.

Similar to the application traffic entering the network, there could be other traffic like BGP messages for Internet peers, VPN tunnels traffic, as well other services like email/DNS, etc. There are means to protect every one of these, like using authentication mechanisms (password or key-based) for peers of BGP, VPN, and whitelisting these specific peers to make inbound connections (in perimeter filters). Along with these, the amount of messages/traffic can be rate-limited to known scale or expected load, so the resources are not overwhelmed.

DDoS mitigation

Protecting against a DDoS attack is another important aspect. The attack traffic will look similar to the genuine users/client request, but with the intention to flood the externally exposed app, which could be a web server, DNS, etc. Therefore it is essential to differentiate between the attack traffic and genuine traffic, for this, there are different methods to do at the application level, one such example using Captcha on a web service, to catch traffic originating from bots.

For these methods to be useful, the nodes should be capable of handling both the attack traffic and genuine traffic. It may be possible in cloud-based infrastructure to dynamically add more virtual machines/resources, to handle the sudden spike in volume of traffic, but on-prem, the option to add additional resources might be challenging.

To handle a large volume of attack traffic, there are solutions available, which can inspect the packets/traffic flows and identify anomalies (i.e.) traffic patterns that don't resemble a genuine connection, like client initiating TCP connection, but fail to complete the handshake, or set of sources, which have abnormally huge traffic flow. Once this unwanted traffic is identified, these are dropped at the edge of the network itself, thereby protecting the resources of app nodes. This topic alone can be discussed more in detail, but that will be beyond the scope of this section.

Network Demarcation

Network demarcation is another common strategy deployed in different networks when applications are grouped based on their security needs and vulnerability to an attack. Some common demarcations are, the external/internet facing nodes are grouped into a separate zone, whereas those nodes having sensitive data are segregated into a separate zone. And any communication between these zones is restricted with the help of security tools to limit exposure to unwanted hosts/ports. These inter-zone communication filters are sometimes called ring-fencing. The number of zones to be created, varies for different deployments, for example, there could be a host which should be able to communicate to the external world as well as internal servers, like proxy, email, in this case, these can be grouped under one zone, say De-Militarized Zones (DMZ). The main advantage of creating zones is that, even if there is a compromised host, that doesn't act as a back door entry for the rest of the infrastructure.

Node protection

Be it server, router, switches, load balancers, firewall, etc, each of these devices come with certain capabilities to secure themselves, like support for filters (e.g. Access-list, Iptables) to control what traffic to process and what to drop, anti-virus software can be used in servers to check on the software installed in them.

Operational practices

There are numerous security threats for infrastructure, and there are different solutions to defend them. The key part to the defence, is not only identifying the right solution and the tools for it but also making sure there are robust operational procedures in place, to respond promptly, decisively and with clarity, for any security incident.

Standard Operating Procedures (SOP)

SOP need to be well defined and act as a reference for on-call to follow during a security incident. This SoP should cover things like,

  • When a security incident happens, how it will be alerted, to whom it will be alerted.

  • Identify the scale and severity of the security incident.

  • Who are the points of escalation and the threshold/time to intimate them, there could be other concerned teams or to the management or even to the security operations in-charge.

  • Which solutions to use (and the procedure to follow in them) to mitigate the security incident.

  • Also the data about the security incident has to be collated for further analysis.

Many organisations have a dedicated team focused on security, and they drive most of the activities, during an attack and even before, to come up with best practices, guidelines and compliance audits. It is the responsibility of respective technical teams, to ensure the infrastructure meets these recommendations and gaps are fixed.

Periodic review

Along with defining SoP's, the entire security of the infrastructure has to be reviewed periodically. This review should include,

  • Identifying any new/improved security threat that could potentially target the infrastructure.

  • The SoP's have to be reviewed periodically, depending upon new security threats or changes in the procedure (to implement the solutions)

  • Ensuring software upgrades/patches are done in a timely manner.

  • Audit the infrastructure for any non-compliance of the security standards.

  • Review of recent security incidents and find means to improvise the defence mechanisms.